Core Curriculum Assessment Report 2011 12

Core Curriculum Assessment Report 2011_12

Department

Representative

Course Name / number

Physics

Dr. Chin‐Che Tin

PHYS1600/1617, PHYS1610/1617

SLO(s) being assessed: Student will..

AGSC Content Area of Alignment:

Assessment Method(s):

Findings: What assessment data did each assessment method produce?

2.

3.

4.

[Explain how assessment for the measures associated with this SLO ‐ not grading for the course as a whole ‐ was conducted. You my cut/paste rubics for inclusion here, identify faculty reviewing committees, or identify specific kinds of test questions important to your method. Is this the method you initially planned to use? Provide a separate paragraph for each method].

1.

SLO 10: Students will understand and appreciate methods and issues of science and technology.

The assessment of these courses comes under the purview of the Physics Department’s Learning Improvement Committee for Introductory Physics with Calculus, chaired by Dr. Chin‐Che Tin. The committee believes that learning assessment should not be viewed as a measure of the teaching effectiveness of the instructors. To discourage such unwarranted association and to encourage participation in the assessment efforts, the committee has decided not to identify the instructors. However, during the committee meetings to discuss assessment data, the instructors may choose to identify themselves to aid in the discussion, and many

instructors did.Members of the Learning Improvement Commi ee for Introductory Physics and Astronomy were:Dr. Chin‐Che Tin (Chair)Dr. Yu LinDr. David MaurerDr. Minseo ParkDr. John WilliamsThe Chair of

the committee has also invited other instructors also teaching these courses but who are not members of the commi ee, to the mee ngs.The department has iden fied the following assessment areas: homework

problems, laboratory experiences, classroom interactive sessions, and test questions. Faculty may elect to use any or all of these assessment areas for learning assessment. However the department encourages faculty teaching these courses to use Mastering Physics, which is an online assignment program, as the primary assessment tool. Problems are assigned throughout the semester that relate well to each of these five measures associated with SLO 10 and the performance of our students is compared to the National Average. The instructors can choose to use assign any questions they see fit. To provide guidance as to the appropriate questions to use, the committee has provided a list of questions that they may use, if they want to. However, these courses have several classes each, taught by different instructors. The committee noted that it is most logical for all classes of the same course to use the same set of questions. Therefore, from Spring 2012 onward, instructors using MasteringPhysics are requested to use the same set of questions provided by the

commi ee.In addi on to that, grades from a laboratory experiment were included in the assessments for Spring 2012 for PHYS 1600 and 1610.Data were collected for both Fall 2011 and Spring 2012.The commi ee

met on April 3, 2012, to discuss the assessment data for this course.The commi ee met on September 27, 2012, to discuss the assessment data.PHYS 1600Fall 2011:Several instructors taught this course. They

were Instructors H, I, J and R. Instructors H, J, and R used MasteringPhysics. Instructor I used tests as the mode of assessment.Spring 2012:In this semester, two different instructors K and L taught the

course.Instructor K used MasteringPhysics but Instructor L used quizzes/exam as the mode of assessment. Both instructors chose ques ons from the common set of ques ons provided by the commi ee.PHYS

1610Fall 2011:This course was taught by Instructors P, Q, and R.All used MasteringPhysics.Spring 2012:In this semester, two instructors, N and O, taught the course.Both instructors used MasteringPhysics as the

mode of assessment. All instructors chose questions from the common set of questions provided by the commi ee.PHYS 1607 and PHYS 1617These are Honors Physics I and II respec vely, and they were both

taught by the same instructor M.Instructor M used tests as the mode of assessment.

Area III: Science and Math


Department

Representative


Physics

Dr. Chin‐Che Tin

PHYS1600/1617, PHYS1610/1617

How did you (or will you) use the findings for improvement?5.

[What questions / issues / concerns did your data raise for the faculty teaching the course? What discussion did the faculty have about the findings? What future actions to improve student attainment of this outcome will the department / program take as a result of this analysis?]

For tests/exam, the data reported were the average % score of the class for each ques on. Historically, the average test score for Introductory Physics courses is consistently about 60‐65%.For online assignment using

MasteringPhysics, the data collected were percentage of students completing the assigned problems (% Complete), average percentage score of those students completing the assigned problems (% Average Score), and average percentage national score of students given the same problems in those institutions in the U.S. using MasteringPhysics (% National Score). The % National Score data are derived from a sample of several

thousand students. Historically, the average score is about 90% and the average comple on rate is about 70‐ 80%. PHYS 1600Fall 2011:Instructor H: %Complete: 79.3%Average score: 88.2%Na onal score:

95.4The average score is slightly lower than the na onal average.Instructor I:% Average score: 61This average test score is within the historical range for tests in our Introductory Physics program in our

department.Instructor I should use more ques ons.Instructor J:%Complete: 82.6%Average score: 88.3%Na onal score: 93.1The average score is slightly lower than the na onal average.Spring 2012:

Instructor K:% Complete: 72.1% Average Score: 94.9% Na onal Score: 91.7The average comple on score

is within the historical range for MasteringPhysics in our department.The average score is higher than the na onal average.Instructor L:% Complete: 86% Average Score: 63.5The average comple on score is

higher than in MasteringPhysics because the mode of assessment is quiz/exam. This is to be expected because the quizzes/exam were given during recitation sessions or in class. The average score is within the historical range for tests in our department. The average score cannot be compared to the national score even though the same set of questions was used. This is because MasteringPhysics allows multiple attempts and longer

me dura on.PHYS 1610Fall 2011:Instructor P:% Complete: 86% Average Score: 95% Na onal Score: 94Comple on rate is higher than usual and average score is comparable with the na onal

average.Instructor Q:% Complete: 77.4% Average Score: 93.8% Na onal Score: 94.5Comple on rate is typical and average score is comparable with the na onal average.Instructor R:% Complete: 77.3%

Average Score: 85.5% Na onal Score: 92.4Comple on rate is typical but average score is lower than average na onal score.Spring 2012: Instructor N:% Complete: 84.0% Average Score: 94.4% Na onal Score:

94.3Average comple on rate is slightly higher than historical value. Average score is comparable with na onal average.Instructor O:% Complete: 73.1% Average Score: 85.9% Na onal Score: 94.3Average

comple on rate is typical but average score is lower than na onal average.PHYS 1607Fall 2011:% Average score: 63.4This is within the historical range for tests/exam in Introductory Physics program.PHYS

1617Spring 2012:% Average score: 82.8This test score is significantly higher than normal, indica ng the possibility that the tests were easier.

Some instructors should use more ques ons.Ge ng all the students to do the assignments is a problem.

Mo va on is an issue that instructors have to confront.Those instructors who asked their teaching assistants to discuss assignment problems during recitations would get higher average scores, which only shows that

regular reviews and help during recita ons can be very helpful.Instructor’s Verba m Comments:(Instructor L for PHYS1600‐Spring 2012)The results for PHYS1600 (Spring, 2012) are lower than all other physics courses

due to the methodology employed in obtaining grades. I used exactly the same assessment questions, but in my course, the questions were all assigned as exam or quiz questions instead of using the multi‐attempt,


Department

Representative


Physics

Dr. Chin‐Che Tin

PHYS1600/1617, PHYS1610/1617

Additional Comments:6.

Committee Comments7.

[What else would you like the Committee to know about your assessment of this course or plans for the future?]

online, Mastering Physics system used by the other Physics sections. The average performance recorded for my class was consistent with the student performance on exams and, in my opinion, provides a more realistic evaluation of student performance. For future semesters, I'll continue to work with the students to improve

their prepara on for these problems.(Instructor O for PHYS1610‐Spring 2012)This was my first me teaching Physics 1610. As a result I stayed with a traditional lecture format, including demonstrations to help foster understanding of key physical ideas along with conceptual discussion and example problem

development and solu on on the chalkboard. A main por on of the class discusses the physics of electricity and magnetism. The phenomena introduced are intuitively somewhat difficult for students new to the subject given that they do not have any practical experience with electric and magnetic fields as they do with simple

mechanical systems from everyday life.This mo vated me to make connec on to prac cal examples of the use of the concepts I was discussing to generate interest and make the ideas less abstract. I think this approach was somewhat successful (but have no way to quantify it), given that the students were typically majoring in engineering, and enjoy discussion of applications. I plan on expanding these application discussions the next

me I teach the class as one way to improve student learning.A new element I plan on employing when teaching Physics 1610 again in Spring 2013 will be to incorporate iClickers to foster more interaction with the students during lectures. This will both enable me to gauge students understanding of material rapidly in class

as well as then respond by further discussion of any misunderstanding of specific concepts.

Using a common set of questions for all classes of the same course is a major step forward in our assessment efforts. For Spring 2012, we included data from labs, which is more meaningful for Measure 3. Problem s ll

exists in finding proper ques ons to suit Measures 1 and 4.

Mean of rubric score = 2.94 (out of 4)Since assessment doesn't relate to measures, u lity of findings is ques onable.Since ques ons don't relate to Measures, then no findings can logically emergeMost of the

questions allegedly assessing various measures, with the exception of Measure 5, have little to do with the associated measure(s).

PHYS 1600

Engineering Physics I

H-PHYS1600-Fall 2011

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PHYS 1600 – Engineering Physics I Fall 2011 Instructor H Mode of Assessment: Assignment (MasteringPhysics)

Measures Problems % Complete % Average Score % National Score 1 1.1 84.5 83.7 89.9

1.2 85.7 62.5 99.8 1.3 56.0 93.7 94.8 1.4 54.8 91.9 92.9 1.5 52.4 87.5 85.5

2 2.1 91.7 92.7 98.4 2.2 86.9 88.1 99.8 2.3 78.6 90.9 95.5 2.4 84.5 95.6 91.7 2.5 82.1 95.3 94.8

3 3.1 86.9 93.1 96.2 3.2 83.3 90.2 94.7 3.3 79.8 92.5 92.2 3.4 72.6 93.7 89.4 3.5 76.2 89.3 97.6

4 4.1 77.4 90.9 95.9 4.2 84.5 83.2 94.6 4.3 84.5 60.6 99.7 4.4 78.6 96.9 95.4 4.5 75.0 99.8 96.4

5 5.1 89.3 56.4 99.8 5.2 90.5 89.6 97.2 5.3 85.7 98.4 99.0 5.4 84.5 94.7 98.8 5.5 76.2 94.5 94.0

Average 79.3 88.2 95.4


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PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 The figure shows a motion diagram of a car traveling down a street. The camera took one frame

every 10 s. A distance scale is provided.

1.2 Answer the following true/false questions on the topic "Force and Motion."

a. An object will not accelerate unless there is a net force acting on it. b. An object's acceleration vector a always points in the same direction as its net force vector Fnet. c. An object cannot be in motion unless there is a net force acting on it. d. When the same force is applied to two objects, the more massive object will experience a

greater acceleration. e. The magnitude of the net force acting on an object is equal to the sum of the magnitudes of the

individual forces acting on that object. 1.3 The gravitational force of a star on orbiting planet 1 is F1. Planet 2, which is twice as massive as

planet 1 and orbits at twice the distance from the star, experiences gravitational force F2. What is

the ratio F1F2? 1.4 Three satellites orbit a planet of radius R, as shown in the figure. Satellites S1 and S3 have mass m.

Satellite S2 has mass 2 m. Satellite S1orbits in 250 minutes and the force on S1 is 10,000 N.

a. What is the period of S2? b. What is the period of S3? c. What is the force on S2? d. What is the force on S3? e. What is the kinetic-energy ratio K1/K3 for S1 and S3?


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1.5 The figure shows two planets of mass m orbiting a star of mass M . The planets are in the same orbit, with radius r , but are always at opposite ends of a diameter. Find an exact expression for the orbital period T.

Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 2.1 How many significant figures does each of the following numbers have?

a. 6.21 b. 62.1 c. 0.620 d. 0.062

2.2 Using the approximate conversion factors in table below, convert the following to SI units without using your calculator. a. 20 ft b. 60 mi c. 60 mph d. 8 in

2.3 The position of a particle is given by the function x = (2t3 – 9t2 + 12) m, where t is in s. a. At what time or times is vx = 0 m/s? b. What is the particle's position at this times? c. What is the particle's acceleration at this times?

2.4 The figure shows two of the three forces acting on an object in equilibrium. Redraw the diagram,

showing all three forces. Label the third force F3 .


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2.5 The figure shows two masses at rest. The string is massless and the pulley is frictionless. The spring scale reads in kg. What is the reading of the scale?

Measure 3: Demonstrate an ability to conduct, and interpret the results of experiments aimed at better understanding natural phenomena.

3.1 A bicyclist has the position-versus-time graph shown. a. What is the bicyclist's velocity at t = 10 s? b. What is the bicyclist's velocity at t = 25 s? c. What is the bicyclist's velocity at t = 35 s?

3.2 The velocity-versus-time graph is shown for a particle moving along the x-axis. Its initial position is x0 = 2.0 m at t0 = 0 s .

a. What are the particle's position at t = 1.0 s? b. What are the particle's velocity at t = 1.0 s? c. What are the particle's acceleration at t = 1.0 s? d. What are the particle's position at t = 3.0 s? What are the

particle's position at t = 3.0 s? e. What are the particle's velocity at t = 3.0 s? f. What are the particle's acceleration at t = 3.0 s?

3.3 The figure shows the velocity graph of a 75 kg passenger in an elevator. a. What is the passenger's apparent weight at t = 1.0 s? b. What is the passenger's apparent weight at t = 5.0 s ? c. What is the passenger's apparent weight at t = 9.0 s ?


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3.4 A 2.0 kg wood block is launched up a wooden ramp that is inclined at a 30° angle. The block's initial speed is 10 m/s. The coefficient of kinetic friction of wood on wood is µk = 0.200. a. What vertical height does the block reach above its starting point? b. What speed does it have when it slides back down to its starting point?

3.5 A 2.0 kg object is moving to the right with a speed of 1.0 m/s when it experiences the force shown in the figure. a. What is the object's speed after the force ends? b. What is the object's direction after the force ends?

Measure 4: Understand major issues and problems facing modern science and

technology, including issues related to ethics, cultural values, public policies, and the impact of human activity upon the planet.

4.1 You are driving to the grocery store at 20 m/s. You are 110 m from an intersection when the traffic light turns red. Assume that your reaction time is 0.50 s and that your car brakes with constant acceleration. a. How far are you from the intersection when you begin to apply the brakes? b. What acceleration will bring you to rest right at the intersection? c. How long does it take you to stop after the light turns red?

4.2 You've slammed on the brakes and your car is skidding to a stop while going down a 20° hill. a. Draw a free-body diagram. b. Which of the following is the correct motion diagram for the system described above?


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4.3 While driving to work last year, I was holding my coffee mug in my left hand while changing the CD with my right hand. Then the cell phone rang, so I placed the mug on the flat part of my dashboard. Then, believe it or not, a deer ran out of the woods and on to the road right in front of me. Fortunately, my reaction time was zero, and I was able to stop from a speed of 20 m/s in a mere 50 m, just barely avoiding the deer. Later tests revealed that the static and kinetic coefficients of friction of the coffee mug on the dash are 0.50 and 0.30, respectively; the coffee and mug had a mass of 0.50 kg; and the mass of the deer was 120 kg. Did my coffee mug slide?

4.4 A car drives over the top of a hill that has a radius of 50 m. What maximum speed can the car have without flying off the road at the top of the hill?

4.5 A 2100 kg truck is traveling east through an intersection at 2.0 m/s when it is hit simultaneously from the side and the rear. (Some people have all the luck!) One car is a 1200 kg compact traveling north at 5.0 m/s. The other is a 1500 kg midsize traveling east at 10 m/s. The three vehicles become entangled and slide as one body. What is their speed just after the collision?

Measure 5: Demonstrate knowledge in one area of science, including understanding its

basic principles, laws, and theories.

5.1 a. Determine the sign (positive or negative) of the position for the particle in the figure.

b. Determine the sign (positive or negative) of the velocity for the particle in the figure.

c. Determine the sign (positive or negative) of the acceleration for the particle in the figure.

5.2 The figure shows the position-versus-time graph for a moving object. At which lettered point or points: a. Is the object moving the fastest? b. Is the object speeding up?

5.3 Two rubber bands pulling on an object cause it to accelerate at 1.2 m/s2. a. What will be the object's acceleration if it is pulled by four rubber bands? b. What will be the acceleration of two of these objects glued together if they are pulled by two

rubber bands?

5.4 A woman has a mass of 55 kg. a. What is her weight while standing on earth? b. What is her mass on the moon, where g = 1.62 m/s2? c. What is her weight on the moon?

5.5 What is the acceleration due to gravity of the sun at the distance of the earth's orbit?

I-PHYS1600-Fall 2011

1

PHYS 1600 – Engineering Physics I Fall 2011 Instructor I Mode of Assessment: Tests

Measure Problems % Correct 1 1.1 65

1.2 60 1.3 34 1.4 55

2 2.1 80 3 3.1 53

3.2 52 4 4.1 71 5 5.1 64

5.2 75 Average 61


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PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 10.26 (conservation of energy) A cannon tilted up at a 25º angle fires a cannon ball at 83 m/s from atop a 11 m-high fortress wall. What is the ball's impact speed on the ground below? 13.25 (buoyancy) What is the tension in the string in the figure? 9.66 (conservation of linear momentum) A proton is shot at 5.0×107 m/s toward a gold target. The nucleus of a gold atom, with a mass 197 times that of the proton, repels the proton and deflects it straight back with 90% of its initial speed. What is the recoil speed of the gold nucleus? 9.35 (conservation of angular momentum) Ice skaters often end their performances with spin turns, where they spin very fast about their center of mass with their arms folded in and legs together. Upon ending, their arms extend outward, proclaiming their finish. Not quite as noticeably, one leg goes out as well. Suppose that the moment of inertia of a skater with arms out and one leg extended is 3.1 kg.m2 and for arms and legs in is 0.70 kg.m2. If she starts out spinning at 5.5 rev/s , what is her angular speed (in rev/s) when her arms and one leg open outward? Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 3.52 (Vectors) The bacterium Escherichia coli (or E. coli) is a single-celled organism that lives in the gut of healthy humans and animals. When grown in a uniform medium rich in salts and amino acids, these bacteria swim along zig-zag paths at a constant speed of 20 μm/s. The figure shows the trajectory of an E. coli as it moves from point A to point E. Each segment of the motion can be identified by two letters, such as segment BC. a) For each of the four segments in the bacterium’s

trajectory, calculate the x- and y- components of its displacement and of its velocity.

b) Calculate the total distance traveled and the magnitude of the net displacement for the entire motion.

c) What are the magnitude and the direction of the bacterium’s average velocity for the entire trip?


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14.6 (simple harmonic motion) An air-track glider attached to a spring oscillates between the 13.0 cm mark and the 55.0 cm mark on the track. The glider completes 11.0 oscillations in 32.0 s. What are the (a) period, (b) frequency, (c) amplitude, and (d) maximum speed of the glider? 10.61 (conservation of energy) You have been asked to design a "ballistic spring system" to measure the speed of bullets. A bullet of mass m is fired into a block of mass M. The block, with the embedded bullet, then slides across a frictionless table and collides with a horizontal spring whose spring constant is k. The opposite end of the spring is anchored to a wall. The spring's maximum compression d is measured. a) Find an expression for the bullet's initial speed vB in terms of m, M, k, and d. b) What was the speed of a 1.7 g bullet if the block's mass is 1.5 kg and if the spring, with k = 21 N/m,

was compressed by 16 cm? c) What percentage of the bullet's energy is "lost"? Measure 4: Understand major issues and problems facing modern science and


2.56 (Linear Motion) You are driving to the grocery store at 22 m/s. You are 130 m from an intersection when the traffic light turns red. Assume that your reaction time is 0.73 s and that your car brakes with constant acceleration. a) How far are you from the intersection when you begin to apply the brakes? b) What acceleration will bring you to rest right at the intersection? Measure 5: Demonstrate knowledge in one area of science, including understanding its

basic principles, laws, and theories. 9.27 (linear momentum) Two particles collide and bounce apart. The figure shows the initial momenta of both and the final momentum of particle 2. a) What is the x component of final momentum of particle 1? b) What is the y component of final momentum of particle 1? 6.10 (circular motion) The angular velocity (in rpm) of the blade of a blender is given in the figure. a) If θ = 0 rad at t = 0 s, what is the blade's angular position at t = 20 s? b) At what time has the blade completed 15 full revolutions?

J-PHYS1600-Fall 2011

1

PHYS 1600 – Engineering Physics I Fall 2011 Instructor J Mode of Assessment: Assignment (MasteringPhysics)


1.2 85.3 89.8 92.3 1.3 72.7 88.5 88.1 1.4 80.0 92.0 94.6 1.5 83.3 93.2 97.9 1.6 69.3 90.7 93.3

2 2.1 83.3 80.6 89.5 2.2 91.3 95.9 99.9 2.3 84.0 86.4 87.6 2.4 84.0 93.9 96.5 2.5 74.7 86.7 89.9 2.6 75.3 86.5 92.0

3 3.1 90.0 90.5 93.5 3.2 84.0 95.4 98.0 3.3 82.7 96 96.8 3.4 84.7 90.2 92.9 3.5 88.7 84.3 99.4

4 4.1 77.3 84.3 91.0 4.2 84.0 88.0 91.4 4.3 85.3 90.3 95.5 4.4 79.3 82.8 93.5 4.5 82.7 86.3 98.1

5 5.1 86.7 93.3 92.2 5.2 85.3 85.0 89.9 5.3 81.3 71.2 84.2 5.4 86.0 90.6 95.5 5.5 78.0 79.0 92.7 5.6 84.7 93.0 94.6

Average 82.6 88.3 93.1


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PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 A student standing on the ground throws a ball straight up. The ball leaves the student's hand with a speed of 17.0m/s when the hand is 1.60m above the ground. How long is the ball in the air before it hits the ground? (The student moves her hand out of the way.) 1.2 A proton is traveling to the right at 2.0×107 m/s. It has a head-on perfectly elastic collision with a carbon atom. The mass of the carbon atom is 12 times the mass of the proton. a) What are the speeds of each after the collision? b) What is the direction of the proton after the collision? c) What is the direction of the carbon atom after the collision? 1.3 A 45kg figure skater is spinning on the toes of her skates at 1.0 rev/s. Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40 kg, 20 cm average diameter, 160 cm tall) plus two rod-like arms (2.5 kg each, 66 cm long) attached to the outside of the torso. The skater then raises her arms straight above her head, where she appears to be a 45 kg, 20-cm-diameter, 200-cm-tall cylinder. What is her new rotation frequency, in revolutions per second? 1.4 What is the tension in the string?

1.5 It is said that Galileo discovered a basic principle of the pendulum-that the period is independent of the amplitude-by using his pulse to time the period of swinging lamps in the cathedral as they swayed in the breeze. Suppose that one oscillation of a swinging lamp takes 5.5s. a) How long is the lamp chain? b) What maximum speed does the lamp have if its maximum angle from vertical is 3.0º ?


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1.6 In 1866, the German scientist Adolph Kundt developed a technique for accurately measuring the speed of sound in various gases. A long glass tube, known today as a Kundt's tube, has a vibrating piston at one end and is closed at the other. Very finely ground particles of cork are sprinkled in the bottom of the tube before the piston is inserted. As the vibrating piston is slowly moved forward, there are a few positions that cause the cork particles to collect in small, regularly spaced piles along the bottom. The figure shows an experiment in which the tube is filled with pure oxygen and the piston is driven at 400 Hz. What is the speed of sound in oxygen?

Measure 2: Understand the scientific method and demonstrate an ability to apply it across a variety of situations. 2.1 A particle's position on the x-axis is given by the function x = (t2 – 2.00 t + 5.00) m, where t is in s. Where is the particle when vx= 6.00 m/s? 2.2 Let A = 6 i + 2 j, B = -2 i -5 j, and D = A - B. a) Write vector D in component form. b) What is the magnitude of vector D ? c) What is the direction of vector D ? 2.3 Three forces are exerted on an object placed on a slope in the figure . The forces are measured in newtons (N). a) Assuming that forces are vectors, what is the component of the

net force Fnet = F1 + F2 + F3 parallel to the slope? b) What is the component of Fnet perpendicular to the slope? c) What is the magnitude of Fnet? d) What is the direction of Fnet? 2.4 How much work is done by the force F = (8.00 i – 1.30 j)N on a particle that moves through displacement (a) r = 3.50 i m and (b) r = 3.50 j m ? 2.5 Force F = –14j N is exerted on a particle at r = (5i + 5 j)m. What is the torque on the particle about the origin?


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2.6 One day when you come into physics lab you find several plastic hemispheres floating like boats in a tank of fresh water. Each lab group is challenged to determine the heaviest rock that can be placed in the bottom of a plastic boat without sinking it. You get one try. Sinking the boat gets you no points, and the maximum number of points goes to the group that can place the heaviest rock without sinking. You begin by measuring one of the hemispheres, finding that it has a mass of 25g and a diameter of 8.6cm .What is the mass of the heaviest rock that, in perfectly still water, won't sink the plastic boat? Measure 3: Demonstrate an ability to conduct, and interpret the results of experiments

aimed at better understanding natural phenomena. 3.1 The velocity-versus-time graph is shown for a particle moving along the x-axis. Its initial position is x0 = 2.0m at t0 = 0 s. a) What are the particle's position at t = 1.0 s? b) What are the particle's velocity at t = 1.0 s? c) What are the particle's acceleration at t = 1.0 s? d) What are the particle's position at t = 3.0 s? e) What are the particle's velocity at t = 3.0 s? f) What are the particle's acceleration at t = 3.0 s? 3.2 While at the county fair, you decide to ride the Ferris wheel. Having eaten too many candy apples and elephant ears, you find the motion somewhat unpleasant. To take your mind off your stomach, you wonder about the motion of the ride. You estimate the radius of the big wheel to be 15 m, and you use your watch to find that each loop around takes 25 s. a) What is your speed? b) What is the magnitude of your acceleration? c) What is the ratio of your weight at the top of the ride to your weight while standing on the ground? d) What is the ratio of your weight at the bottom of the ride to your weight while standing on the ground? 3.3 You need to determine the density of a ceramic statue. If you suspend it from a spring scale, the scale reads 28.4 N. If you then lower the statue into a tub of water, so that it is completely submerged, the scale reads 17.0 N. What is the density? 3.4 You've always wondered about the acceleration of the elevators in the 101-story-tall Empire State Building. One day, while visiting New York, you take your bathroom scale into the elevator and stand on it. The scale reads 150 lb as the door closes. The reading varies between 120 lb and 170 lb as the elevator travels 101 floors. a) What is the maximum acceleration upward? b) What is the maximum magnitude of the acceleration downward?


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3.5 A physics student on Planet Exidor throws a ball, and it follows the parabolic trajectory shown in the figure . The ball's position is shown at 1s intervals until t = 3s. At t = 1s, the ball's velocity is v = (2.0 i – 2.0 j) m/s. a) Determine the ball's velocity at t = 0s. b) Determine the ball's velocity at t = 2s. c) Determine the ball's velocity at t = 3s. d) What is the value of g on Planet Exidor? e) What was the ball's launch angle? Measure 4: Understand major issues and problems facing modern science and


4.1 Seat belts and air bags save lives by reducing the forces exerted on the driver and passengers in an automobile collision. Cars are designed with a "crumple zone" in the front of the car. In the event of an impact, the passenger compartment decelerates over a distance of about 1 m as the front of the car crumples. An occupant restrained by seat belts and air bags decelerates with the car. By contrast, an unrestrained occupant keeps moving forward with no loss of speed (Newton's first law!) until hitting the dashboard or windshield. These are unyielding surfaces, and the unfortunate occupant then decelerates over a distance of only about 5 mm. a) A 60 kg person is in a head-on collision. The car's speed at impact is 20 m/s. Estimate the net force

on the person if he or she is wearing a seat belt and if the air bag deploys. b) Estimate the net force that ultimately stops the person if he or she is not restrained by a seat belt or air

bag. c) What is the force in part (a) in terms of the person's weight? d) What is the force in part (b) in terms of the person's weight?

4.2 A highway curve of radius 560 m is designed for traffic moving at a speed of 73.0 km/hr. What is the correct banking angle of the road?

4.3 Most geologists believe that the dinosaurs became extinct 65 million years ago when a large comet or asteroid struck the earth, throwing up so much dust that the sun was blocked out for a period of many months. Suppose an asteroid with a diameter of 2.0 km and a mass of 1.0×1013 kg hits the earth with an impact speed of 4.0×104 m/s. a) What is the earth's recoil speed after such a collision? (Use a reference frame in which the earth was

initially at rest.) b) What percentage is this of the earth's speed around the sun? (Use the astronomical data in the

textbook.)

4.4 Truck brakes can fail if they get too hot. In some mountainous areas, ramps of loose gravel are constructed to stop runaway trucks that have lost their brakes. The combination of a slight upward slope and a large coefficient of rolling friction as the truck tires sink into the gravel brings the truck safely to a halt. Suppose a gravel ramp slopes upward at 6.0° and the coefficient of rolling friction is 0.40. Use work and energy to find the length of a ramp that will stop a 15,000 kg truck that enters the ramp at 35m/s (≈ 75mph).


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4.5 In a hydroelectric dam, water falls 28.0m and then spins a turbine to generate electricity. a) What is ΔU of 1.0 kg of water? b) Suppose the dam is 80% efficient at converting the water's potential energy to electrical energy. How

many kilograms of water must pass through the turbines each second to generate 52.0MW of electricity? This is a typical value for a small hydroelectric dam.


basic principles, laws, and theories. 5.1 A supply plane needs to drop a package of food to scientists working on a glacier in Greenland. The plane flies 120 m above the glacier at a speed of 150 m/s. How far short of the target should it drop the package? 5.2 The 2.0kg wood box in the figure slides down a vertical wood wall while you push on it at a 45º angle. What magnitude of force should you apply to cause the box to slide down at a constant speed? 5.3 Two packages at UPS start sliding down the 20º ramp shown in the figure. Package A has a mass of 7.00kg and a coefficient of kinetic friction of 0.220. Package B has a mass of 12.0 kg and a coefficient of kinetic friction of 0.170. How long does it take package A to reach the bottom? 5.4 Communications satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the earth rotates. These are called geosynchronous orbits. The altitude of a geosynchronous orbit is 3.58×107 m (≈ 22,000 miles). a) What is the period of a satellite in a geosynchronous orbit? b) Find the value of g at this altitude. c) What is the apparent weight of a 2000 kg satellite in a geosynchronous orbit? 5.5 The carbon isotope 14C is used for carbon dating of archeological artifacts. 14C (mass 2.34×10-26 kg) decays by the process known as beta decay in which the nucleus emits an electron (the beta particle) and a subatomic particle called a neutrino. In one such decay, the electron and the neutrino are emitted at right angles to each other. The electron (mass 9.11×10-31 kg) has a speed of 6.00×107 m/s and the neutrino has a momentum of 8.10×10−24 kg·m/s. What is the recoil speed of the nucleus? 5.6 As a 1.5×104 kg jet plane lands on an aircraft carrier, its tail hook snags a cable to slow it down. The cable is attached to a spring with spring constant 6.3×104 N/m. If the spring stretches 33m to stop the plane, what was the plane's landing speed?

R-PHYS1600-Fall 2011

1

PHYS 1600 – Engineering Physics I Fall 2011 Instructor R Mode of Assessment: Assignment (MasteringPhysics)

Measures Problems % Complete % Average Score 1 1.1 6.6 19.5

1.2 58.3 68.4 1.3 42.4 74.7 1.4 68.9 68.2 1.5 60.9 55.5

2 2.1 54.3 72.7 2.2 76.8 90.9 2.3 68.2 87.6 2.4 67.5 88.2 2.5 68.9 91.3

3 3.1 49.0 71.6 3.2 66.9 85.9 3.3 37.1 49.8 3.4 72.8 82.1 3.5 57.6 58.8

4 4.1 47.0 63.4 4.2 61.6 87.0 4.3 49.0 85.5 4.4 65.6 83.8 4.5 65.6 81.9

5 5.1 47.7 62.5 5.2 65.6 82.4 5.3 61.6 54.9 5.4 71.5 83.8 5.5 63.6 67.9

Average 58.2 72.7


2

PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 Figure shows three hanging masses connected by massless strings over two massless, frictionless pulleys. a) Find the acceleration constraint for this system. It is a

single equation relating a1y, a2y and a3y. Hint: yA is not a constant.

b) Find an expression for the tension in string A. Hint: You should be able to write four second-law equations. These, plus the acceleration constraint, are five equations in five unknowns.

c) Suppose: m1 = 2.5 kg, m2 = 1.5 kg, m3 = 4 kg. Find the acceleration of each.

d) The 4.0 kg mass would appear to be in equilibrium. Explain why it accelerates.

1.2 A small ball rolls around a horizontal circle at height y inside a frictionless hemispherical bowl of radius R, as shown in the figure a) Find an expression for the ball's angular velocity in

terms of R, y, and g. b) What is the minimum value of ω for which the ball can

move in a circle? c) What is ω in rpm if R = 29cm and the ball is halfway

up? 1.3 A particle has potential energy U(x) = x + sin((2 rad/m)x) over the range 0 m ≤ x ≤ π m. Where are the equilibrium positions in this range? 1.4 A particle of mass m starts from x0 = 0 m with v0 ＞0 m/s. The particle experiences the variable force Fx = F0 sin (cx) as it moves to the right along the x -axis, where F0 and c are constants. a) What are the units of F0? b) What are the units of c? c) At what position xmax does the force first reach a maximum value? Your answer will be in terms of the

constants F0 and c and perhaps other numerical constants. d) What is the particle's velocity as it reaches xmax? Give your answer in terms of m, v0, F0, and c.


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1.5 The two blocks in the figure are connected by a massless rope that passes over a pulley. The pulley is 14cm in diameter and has a mass of 2.4 kg . As the pulley turns, friction at the axle exerts a torque of magnitude 0.51 Nm . If the blocks are released from rest, how long does it take the 4.0 kg block to reach the floor? Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 2.1 Blocks with masses of 1kg , 4 kg , and 6 kg are lined up in a row on a frictionless table. All three are pushed forward by a 55N force applied to the 1 kg block. a) How much force does the 4 kg block exert on the 6 kg block? b) How much force does the 4 kg block exert on the 1 kg block? 2.2 The figure shows the velocity graph of a 2.5 kg object as it moves along the x-axis. a) What is the net force acting on this object at t= 1s? b) What is the net force acting on this object at t = 4 s? c) What is the net force acting on this object at t = 7s? 2.3 A student places her 330 g physics book on a frictionless table. She pushes the book against a spring, compressing the spring by 6.00 cm, then releases the book. What is the book's speed as it slides away? The spring constant is 1500 N/m. 2.4 Doug pushes a 4.50kg crate up a 2.30-m-high 20° frictionless slope by pushing it with a constant horizontal force of 27.0N . a) What is the speed of the crate as it reaches the top of the slope? Solve this problem using work and

energy. b) Solve the problem using Newton's laws.


4

2.5 Starting from rest, a 12-cm-diameter compact disk takes 3.0 s to reach its operating angular velocity of 2000 rpm. Assume that the angular acceleration is constant. The disk's moment of inertia is 2.5×10-5

kg·m2. a) How much torque is applied to the disk? b) How many revolutions does it make before reaching full speed? Measure 3: Demonstrate an ability to conduct, and interpret the results of experiments

aimed at better understanding natural phenomena. 3.1 A mobile at the art museum has a 2.0 kg steel cat and a 4.0 kg steel dog suspended from a lightweight cable, as shown in the figure. It is found that θ1= 27° when the center rope is adjusted to be perfectly horizontal. a) What is the tension in the rope 3? b) What is the angle of rope 3? 3.2 A 3.5×1010 kg asteroid is heading directly toward the center of the earth at a steady 24 km/s. To save the planet, astronauts strap a giant rocket to the asteroid perpendicular to its direction of travel. The rocket generates 5.0×109 N of thrust. The rocket is fired when the asteroid is 4.7×106 km away from earth. You can ignore the rotational motion of the earth and asteroid around the sun. a) If the mission fails, how many hours is it until the asteroid impacts the earth? b) The radius of the earth is 6400 km. By what minimum angle must the asteroid be deflected to just

miss the earth? c) The rocket fires at full thrust for 320s before running out of fuel. Is the earth saved? 3.3 A block of mass m slides down a frictionless track, then around the inside of a circular loop-the-loop of radius R. From what minimum height h must the block start to make it around the loop without falling off? Give your answer as a multiple of R. 3.4 A particle moving along the y-axis has the potential energy U = 3.8y3 J, where y is in m. a) What is the y-component of the force on the particle at y = 0 m? b) What is the y-component of the force on the particle at y = 1 m? c) What is the y-component of the force on the particle at y = 2 m? 3.5 A 250g toy car is placed on a narrow 62-cm-diameter track with wheel grooves that keep the car going in a circle. The 1.5 kg track is free to turn on a frictionless, vertical axis. The spokes have negligible mass. After the car's switch is turned on, it soon reaches a steady speed of 0.79m/s relative to the track. What then is the track's angular velocity, in rpm?


5

Measure 4: Understand major issues and problems facing modern science and technology, including issues related to ethics, cultural values, public policies, and the impact of human activity upon the planet.

4.1 Two packages at UPS start sliding down the 20° ramp shown in the figure. Package A has a mass of 3.50kg and a coefficient of kinetic friction of 0.210. Package B has a mass of 8.00kg and a coefficient of kinetic friction of 0.170. How long does it take package A to reach the bottom?

4.2 A 100g ball moves in a vertical circle on a 1.09 m -long string. If the speed at the top is 4.50 m/s, then the speed at the bottom will be 7.94 m/s. a) What is the gravitational force acting on the ball? b) What is the tension in the string when the ball is at the top? c) What is the tension in the string when the ball is at the bottom? 4.3 A sled starts from rest at the top of the frictionless, hemispherical, snow-covered hill shown in the figure. a) Find an expression for the sled's speed when it is at angle ϕ. b) Use Newton's laws to find the maximum speed the sled can have at

angle ϕ without leaving the surface. c) At what angle ϕmax does the sled "fly off" the hill? 4.4 A 4.5kg box slides down a 4.1-m-high frictionless hill, starting from rest, across a 2.2-m-wide horizontal surface, then hits a horizontal spring with spring constant 500N/m . The other end of the spring is anchored against a wall. The ground under the spring is frictionless, but the 2.2-m-long horizontal surface is rough. The coefficient of kinetic friction of the box on this surface is 0.22. a) What is the speed of the box just before reaching the rough surface? b) What is the speed of the box just before hitting the spring? c) How far is the spring compressed? d) Including the first crossing, how many complete trips will the box make across the rough surface before coming to rest? 4.5 The marble rolls down a track and around a loop-the-loop of radius R. The marble has mass m and radius r. What minimum height h must the track have for the marble to make it around the loop-the-loop without falling off?


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Measure 5: Demonstrate knowledge in one area of science, including understanding its basic principles, laws, and theories.

5.1 A 5.8kg box is on a frictionless 41° slope and is connected via a massless string over a massless, frictionless pulley to a hanging 2.0kg weight. a) What is the tension in the string if the 5.8kg box is held in place, so that it cannot move? b) If the box is then released, which way will it move on the slope? c) What is the tension in the string once the box begins to move? 5.2 In an amusement park ride called The Roundup, passengers stand inside a 19.0m -diameter rotating ring. After the ring has acquired sufficient speed, it tilts into a vertical plane, as shown in the figure a) Suppose the ring rotates once every 4.20 s. If a rider's mass is 58.0kg, with how much force does the

ring push on her at the top of the ride? b) Suppose the ring rotates once every 4.20 s. If a rider's mass is 58.0kg, with how much force does the

ring push on her at the bottom of the ride? c) What is the longest rotation period of the wheel that will prevent the riders from falling off at the top? 5.3 It's your birthday, and to celebrate you're going to make your first bungee jump. You stand on a bridge 110m above a raging river and attach a 31-m-long bungee cord to your harness. A bungee cord, for practical purposes, is just a long spring, and this cord has a spring constant of 42N/m . Assume that your mass is 76 kg . After a long hesitation, you dive off the bridge. How far are you above the water when the cord reaches its maximum elongation? 5.4 A 10 g particle has the potential energy shown in the figure a) How much work does the force do as the particle moves from x = 2 cm

to x = 6 cm? b) What speed does the particle need at x = 2 cm to arrive at x = 6 cm with a

speed of 10 m/s? 5.5 A 120-cm-wide sign hangs from a 5.4kg , 200-cm-long pole. A cable of negligible mass supports the end of the rod as shown in the figure. What is the maximum mass of the sign if the maximum tension in the cable without breaking is 340N ?

KL-PHYS1600-Spring 2012

1

PHYS 1600 – Engineering Physics I Spring 2012 Instructors K and L Mode of Assessment: Instructor K - Assignment (MasteringPhysics) Instructor L – Tests (Both use same problems as given below.)

Measures Problems % Complete % Average Score

% National Score

Instructor K

Instructor L

Instructor K

Instructor L

1 1.1 79.8 76 95.1 76.9 86.21 1.2 72.9 71 94.7 66.5 95.20 1.3 63.6 94 90.2 30.7 88.57 1.4 71.3 98.9 95.42 1.5 72.9 97.9 94.69 1.6 68.2 96.6 93.59

2 2.1 73.6 100 96.8 70.5 89.25 2.2 75.2 100 97.2 52.3 98.72 2.3 77.5 76 96.7 86.9 89.39 2.4 73.6 94 95.3 63.9 96.90 2.5 63.6 94 84.1 46.0 89.68

3 3.1 76.0 100 98.8 61.5 96.52 3.2 75.2 99.0 91.98 3.3 78.3 100 96.8 31.3 94.51 3.4

(Lab)

97.2 96.6

4 4.1 69.8 100 85.6 44.4 73.65 4.2 71.3 76 94.6 81.3 92.46

4.3 73.6 52 94.7 57.4 91.42

4.4 71.3 93.5 90.93

4.5 69.0 71 93.3 59.9 93.21 5 5.1 77.5 76 99.0 80.2 92.25

5.2 71.3 75 93.5 63.5 84.20 5.3 65.9 100 89.4 73.4 92.99 5.4 72.9 98.9 94.77 5.5 66.7 95.3 94.42

Average 72.1 86 94.9 63.5 91.7


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PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 A student standing on the ground throws a ball straight up. The ball leaves the student's hand with a speed of 17.0m/s when the hand is 1.60m above the ground. How long is the ball in the air before it hits the ground? (The student moves her hand out of the way.) 1.2 A proton is traveling to the right at 2.0×107 m/s. It has a head-on perfectly elastic collision with a carbon atom. The mass of the carbon atom is 12 times the mass of the proton. a) What are the speeds of each after the collision? b) What is the direction of the proton after the collision? c) What is the direction of the carbon atom after the collision? 1.3 A 45kg figure skater is spinning on the toes of her skates at 1.0 rev/s. Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40 kg, 20 cm average diameter, 160 cm tall) plus two rod-like arms (2.5 kg each, 66 cm long) attached to the outside of the torso. The skater then raises her arms straight above her head, where she appears to be a 45 kg, 20-cm-diameter, 200-cm-tall cylinder. What is her new rotation frequency, in revolutions per second? 1.4 It is said that Galileo discovered a basic principle of the pendulum-that the period is independent of the amplitude-by using his pulse to time the period of swinging lamps in the cathedral as they swayed in the breeze. Suppose that one oscillation of a swinging lamp takes 5.5s. a) How long is the lamp chain? b) What maximum speed does the lamp have if its maximum angle from vertical is 3.0º ? 1.5 What is the tension in the string?


3

1.6 In 1866, the German scientist Adolph Kundt developed a technique for accurately measuring the speed of sound in various gases. A long glass tube, known today as a Kundt's tube, has a vibrating piston at one end and is closed at the other. Very finely ground particles of cork are sprinkled in the bottom of the tube before the piston is inserted. As the vibrating piston is slowly moved forward, there are a few positions that cause the cork particles to collect in small, regularly spaced piles along the bottom. The figure shows an experiment in which the tube is filled with pure oxygen and the piston is driven at 400 Hz. What is the speed of sound in oxygen? Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 2.1 A particle's position on the x-axis is given by the function x = (t2 – 2.00 t + 5.00) m, where t is in s. Where is the particle when vx= 6.00 m/s? 2.2 Three forces are exerted on an object placed on a slope in the figure . The forces are measured in newtons (N). a) Assuming that forces are vectors, what is the component of the

net force Fnet = F1 + F2 + F3 parallel to the slope? b) What is the component of Fnet perpendicular to the slope? c) What is the magnitude of Fnet? d) What is the direction of Fnet? 2.3 Let A = 6 i + 2 j, B = -2 i -5 j, and D = A - B. a) Write vector D in component form. b) What is the magnitude of vector D ? c) What is the direction of vector D ? 2.4 How much work is done by the force F = (8.00 i – 1.30 j)N on a particle that moves through displacement (a) r = 3.50 i m and (b) r = 3.50 j m ? 2.5 Force F = –14j N is exerted on a particle at r = (5i + 5 j)m. What is the torque on the particle about the origin?


4


3.1 A physics student on Planet Exidor throws a ball, and it follows the parabolic trajectory shown in the figure . The ball's position is shown at 1s intervals until t = 3s. At t = 1s, the ball's velocity is v = (2.0 i – 2.0 j) m/s. a) Determine the ball's velocity at t = 0s. b) Determine the ball's velocity at t = 2s. c) Determine the ball's velocity at t = 3s. d) What is the value of g on Planet Exidor? e) What was the ball's launch angle? 3.2 You've always wondered about the acceleration of the elevators in the 101-story-tall Empire State Building. One day, while visiting New York, you take your bathroom scale into the elevator and stand on it. The scale reads 150 lb as the door closes. The reading varies between 120 lb and 170 lb as the elevator travels 101 floors. a) What is the maximum acceleration upward? b) What is the maximum magnitude of the acceleration downward? 3.3 While at the county fair, you decide to ride the Ferris wheel. Having eaten too many candy apples and elephant ears, you find the motion somewhat unpleasant. To take your mind off your stomach, you wonder about the motion of the ride. You estimate the radius of the big wheel to be 15 m, and you use your watch to find that each loop around takes 25 s. a) What is your speed? b) What is the magnitude of your acceleration? c) What is the ratio of your weight at the top of the ride to your weight while standing on the ground? d) What is the ratio of your weight at the bottom of the ride to your weight while standing on the ground? 3.4 Lab: Archimedes’ Principle: The experiment on Archimedes’ Principle conducted in the undergraduate laboratory consisted of the following tasks: a) Determine the volume of the ring/tube using Archimedes’ Principle and compare your results to the

volume of the ring/tube calculated from physical measurements. Assume that the density of the water is 1.0 g/cm3. Neatly show all work and provide all necessary data. If the TA cannot duplicate your results from the data that you provide, your score will be drastically reduced.

b) Determine the minimum number of pennies required to sink your block if the pennies are loaded on the block uniformly. Pennies minted after 1983 have an average mass of 2.49 grams. Assume that the density of the water is 1.0 g/cm3. Neatly show all work and provide all necessary data. If the TA cannot duplicate your results from the data that you provide, your score will be drastically reduced.


5


4.1 I was driving along at 22 m/s, trying to change a CD and not watching where I was going. When I looked up, I found myself 46 m from a railroad crossing. And wouldn't you know it, a train moving at 30 m/s was only 56 m from the crossing. In a split second, I realized that the train was going to beat me to the crossing and that I didn't have enough distance to stop. My only hope was to accelerate enough to cross the tracks before the train arrived. If my reaction time before starting to accelerate was 0.40s, what minimum acceleration did my car need for me to be here today writing these words? 4.2 Seat belts and air bags save lives by reducing the forces exerted on the driver and passengers in an automobile collision. Cars are designed with a "crumple zone" in the front of the car. In the event of an impact, the passenger compartment decelerates over a distance of about 1 m as the front of the car crumples. An occupant restrained by seat belts and air bags decelerates with the car. By contrast, an unrestrained occupant keeps moving forward with no loss of speed (Newton's first law!) until hitting the dashboard or windshield. These are unyielding surfaces, and the unfortunate occupant then decelerates over a distance of only about 5 mm. a) A 60 kg person is in a head-on collision. The car's speed at impact is 20 m/s. Estimate the net force

on the person if he or she is wearing a seat belt and if the air bag deploys. b) Estimate the net force that ultimately stops the person if he or she is not restrained by a seat belt or air

bag. c) What is the force in part (a) in terms of the person's weight? d) What is the force in part (b) in terms of the person's weight? 4.3 A highway curve of radius 560 m is designed for traffic moving at a speed of 73.0 km/hr. What is the correct banking angle of the road? 4.4 Most geologists believe that the dinosaurs became extinct 65 million years ago when a large comet or asteroid struck the earth, throwing up so much dust that the sun was blocked out for a period of many months. Suppose an asteroid with a diameter of 2.0 km and a mass of 1.0×1013 kg hits the earth with an impact speed of 4.0×104 m/s. a) What is the earth's recoil speed after such a collision? (Use a reference frame in which the earth was

initially at rest.) b) What percentage is this of the earth's speed around the sun? (Use the astronomical data in the

textbook.)

4.5 Truck brakes can fail if they get too hot. In some mountainous areas, ramps of loose gravel are constructed to stop runaway trucks that have lost their brakes. The combination of a slight upward slope and a large coefficient of rolling friction as the truck tires sink into the gravel brings the truck safely to a halt. Suppose a gravel ramp slopes upward at 6.0° and the coefficient of rolling friction is 0.40. Use work and energy to find the length of a ramp that will stop a 15,000 kg truck that enters the ramp at 35m/s (≈ 75mph).


6


5.1 A supply plane needs to drop a package of food to scientists working on a glacier in Greenland. The plane flies 120 m above the glacier at a speed of 150 m/s. How far short of the target should it drop the package? 5.2 Two packages at UPS start sliding down the 20º ramp shown in the figure. Package A has a mass of 7.00kg and a coefficient of kinetic friction of 0.220. Package B has a mass of 12.0 kg and a coefficient of kinetic friction of 0.170. How long does it take package A to reach the bottom? 5.3 The carbon isotope 14C is used for carbon dating of archeological artifacts. 14C (mass 2.34×10-26 kg) decays by the process known as beta decay in which the nucleus emits an electron (the beta particle) and a subatomic particle called a neutrino. In one such decay, the electron and the neutrino are emitted at right angles to each other. The electron (mass 9.11×10-31 kg) has a speed of 6.00×107 m/s and the neutrino has a momentum of 8.10×10−24 kg·m/s. What is the recoil speed of the nucleus? 5.4 As a 1.5×104kg jet plane lands on an aircraft carrier, its tail hook snags a cable to slow it down. The cable is attached to a spring with spring constant 6.3×104 N/m. If the spring stretches 33m to stop the plane, what was the plane's landing speed? 5.5 A guitar string with a linear density of 1.80 g/m is stretched between supports that are 50.0cm apart. The string is observed to form a standing wave with three antinodes when driven at a frequency of 440 Hz. a) What is the frequency of the fifth harmonic of this string? b) What is the tension in the string?

PHYS 1610

Engineering Physics II

P-PHYS1610-Fall 2011

1

PHYS 1610 – Engineering Physics II Fall 2011 Instructor P Mode of Assessment: Assignment (MasteringPhysics)

Measure Item % Complete % Average % National 1 1.1 95 94 95

1.2 96 83 93 1.3 87 98 95 1.4 87 99 99 1.5 92 97 94

2 2.1 87 98 97 2.2 86 98 97 2.3 79 93 94 2.4 79 94 94 2.5 79 96 96

3 3.1 86 88 89 3.2 83 98 88 3.3 83 98 83 3.4 88 98 96 3.5 85 97 96

4 4.1 90 96 95 4.2 86 95 94

5 5.1 85 87 99 5.2 87 97 96 5.3 90 99 98 5.4 88 90 93 5.5 80 96 97

Average 86 95 94


2

PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 A plastic rod that has been charged to -15nC touches a metal sphere. Afterward, the rod's charge is -10nC. (a) What kind of charged particle was transferred between the rod and the sphere, and in which direction? That is, did it move from the rod to the sphere or from the sphere to the rod? (b) How many charged particles were transferred? 1.2 What magnitude charge creates a 1.0 N/C electric field at a point 1.0m away? 1.3 In a semiclassical model of the hydrogen atom, the electron orbits the proton at a distance of 0.053 nm. (a) What is the electric potential of the proton at the position of the electron? (b) What is the electron's potential energy? 1.4 A long, round wire has resistance R. What will the wire's resistance be if you stretch it to twice its initial length?

1.5 The magnetic field at the center of a 1.0-cm-diameter loop is 2.5 mT. (a) What is the current in the loop? (b) A long straight wire carries the same current you found in part a. At what distance from the wire is

the magnetic field 2.5 mT?

Measure 2: Understand the scientific method and demonstrate an ability to apply it across a variety of situations.

2.1 The opening to a cave is a tall, 40.0 cm-wide crack. A bat that is preparing to leave the cave emits a 39.0 kHz ultrasonic chirp. How wide is the "sound beam" 110 m outside the cave opening?

2.2 The wings of some beetles have closely spaced parallel lines of melanin, causing the wing to act as a reflection grating. Suppose sunlight shines straight onto a beetle wing. If the melanin lines on the wing

are spaced 3.0 m apart, what is the first-order diffraction angle for green light ( = 550 nm)? 2.3 A narrow beam of white light is incident on a sheet of quartz. The beam disperses in the quartz, with red

light ( ≈ 700 nm) traveling at an angle of 26.3° with respect to the normal and violet light ( ≈ 400 nm) traveling at 25.7°. The index of refraction of quartz for red light is 1.45. What is the index of refraction of quartz for violet light?


3

2.4 A 1.0-cm-thick layer of water stands on a horizontal slab of glass. Light from a source within the glass is incident on the glass-water boundary. What is the maximum angle of incidence for which the light ray can emerge into the air above the water? 2.5 A 4.0-m-wide swimming pool is filled to the top. The bottom of the pool becomes completely shaded in the afternoon when the sun is 20 degree(s) above the horizon. How deep is the pool?


3.1 The figure shows the light intensity on a screen behind a double slit. The slit spacing is 0.23 mm and the wavelength of the light is 650 nm. What is the distance from the slits to the screen?

3.2 The figure shows the interference pattern on a screen 1.0 m behind an 650 line/mm diffraction grating. What is the wavelength of the light?

3.3 The figure shows the light intensity on a screen behind a single slit. The slit width is 0.18 mm and the screen is 1.4 m behind the slit. What is the wavelength (in nm) of the light?


4

3.4

8.0 g of helium gas follows the process 1 2 3 shown in the figure. (a) Find the value of V1. (b) Find the value of V3. (c) Find the value of p2. (d) Find the value of T3.

3.5 An experiment measures the temperature of a 500 g substance while steadily supplying heat to it. The figure shows the results of the experiment. What is the specific heat of the solid phase? What is the specific heat of the liquid phase? What is the melting temperature? What is the boiling temperature? What is the heat of fusion?



4.1 A 12 V car battery dies not so much because its voltage drops but because chemical reactions increase its internal resistance. A good battery connected with jumper cables can both start the engine and recharge the dead battery. Consider the automotive circuit of the figure. How much current could the good battery alone drive through the starter motor? How much current is the dead battery alone able to drive through the starter motor? With the jumper cables attached, how much current passes through the starter motor? With the jumper cables attached, how much current passes through the dead battery? With the jumper cables attached, in which direction current passes through the dead battery?


5

4.2 An electric generating plant boils water to produce high- pressure steam. The steam spins a turbine that is connected to the generator. How many liters of water must be boiled to fill a 5.0m3 boiler with 50 atm of steam at 400°C? The steam has dropped to 2.0 atm pressure at 150°C as it exits the turbine. How much volume does it now occupy?


basic principles, laws, and theories. 5.1 A 20-cm-radius ball is uniformly charged to 80 nC. (a) What is the ball's uniform charge density C/m3? (b) How much charge is enclosed by spheres of radii 5, 10, and 20 cm? (c) What is the electric field strength at points 5, 10, and 20 cm from the center? 5.2 A hollow metal sphere has 6 cm and 10 cm inner and outer radii, respectively. The surface charge density on the inside surface is -100 nC/m2. The surface charge density on the exterior surface is +100 nC/m2. What is the strength and the direction of the electric field at points 4, 8, and 12 cm from the center? 5.3 The three parallel planes of charge shown in the figure have surface charge densities -(1/2)η, η, and -(1/2) η. Find the electric fields E1 to E4 in regions 1 to 4.

5.4 A long, thin straight wire with linear charge density lambda runs down the center of a thin, hollow metal cylinder of radius R. The cylinder has a net linear charge density 2λ. Assume lambda is positive. Find expressions for the electric field strength (a) inside the cylinder, r < R, and (b) outside the cylinder, r > R. In what direction does the electric field point in each of the cases? 5.5 A spherical shell has inner radius Rin and outer radius Rout. The shell contains total charge Q, uniformly distributed. The interior of the shell is empty of charge and matter.

Find the electric field outside the shell, r Rout.

Find the electric field in the interior of the shell, r Rin.

Find the electric field within the shell, Rin r Rout.

Q-PHYS1610-Fall 2011

1

PHYS 1610 – Engineering Physics II Fall 2011 Instructor Q Mode of Assessment: Assignment (MasteringPhysics)


1.2 78.7 87.6 97.7 1.3 85.4 96.1 93.7 1.4 83.1 98.6 96 1.5 79.8 95.4 98.1

2 2.1 88.8 94.3 90.5 2.2 85.4 96.7 99.4 2.3 69.7 92.6 92 2.4 61.8 78.2 87.3 2.5 77.5 95.7 88.9

3 3.1 75.3 86.6 91.9 3.2 78.7 97.1 98.4 3.3 79.8 100 97.8

4 4.1 88.8 98.7 99.9 4.2 68.5 93.4 97 4.3 82 97.3 94.5 4.4 68.5 98.4 95.1 4.5 51.7 89.1 95.1

5 5.1 86.5 94.8 93.4 5.2 86.5 98.7 99.7 5.3 78.7 94.3 92.4 5.4 71.9 89.1 87.9 5.5 65.2 92.2 87.7

Average 77.4 93.8 94.5


2

PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 A plastic rod that has been charged to -18 nC touches a metal sphere. Afterward, the rod's charge is -9.0 nC. a) What kind of charged particle was transferred between the rod and the sphere, and in which direction?

That is, did it move from the rod to the sphere or from the sphere to the rod? b) How many charged particles were transferred? 1.2 A spherically symmetric charge distribution produces the electric field E = (5600 r2) er N/C, where r is in m. a) What is the electric field strength at r = 16.0 cm ? b) What is the electric flux through a 45.0-cm-diameter spherical surface that is concentric with the

charge distribution? c) How much charge is inside this 45.0-cm-diameter spherical surface? 1.3 In the semiclassical Bohr model of the hydrogen atom, the electron moves in a circular orbit of radius 5.3 × 10-11m with speed 2.2 × 106 m/s. According to this model, what is the magnetic field at the center of a hydrogen atom? (Hint: Determine the average current of the orbiting electron.) 1.4 Light from a sodium lamp (λ = 589nm) illuminates two narrow slits. The fringe spacing on a screen 150cm behind the slits is 4.0 mm. What is the spacing (in mm) between the two slits? 1.5 A 20-cm-diameter cylinder that is 40 cm long contains 50 g of oxygen gas at 20 ºC. a) How many moles of oxygen are in the cylinder? b) How many oxygen molecules are in the cylinder? c) What is the number density of the oxygen? d) What is the reading of a pressure gauge attached to the tank? Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 2.1 a) What is the magnitude of the force F on the 1.0 nC charge in the figure ? b) What is the direction of the force F on the 1.0 nC charge in the figure?


3

2.2 Charge Q is uniformly distributed along a thin, flexible rod of length L. The rod is then bent into the semicircle shown in the figure. a) Find an expression for the electric field E at the center of the semicircle. b) Evaluate the field strength if L = 10cm and Q = 30nC. 2.3 Particle accelerators are used to create well-controlled beams of high-energy particles. Such beams have many uses, both in research and industry. One common type of accelerator is the cyclotron, as shown in the figure. In a cyclotron, a magnetic field confines charged particles to circular paths while an oscillating electric field accelerates them. It is useful to understand the details of this process. Consider a cyclotron in which a beam of particles of positive charge q and mass m is moving along a circular path restricted by the magnetic field B (which is perpendicular to the velocity of the particles). a) Before entering the cyclotron, the particles are accelerated

by a potential difference V. Find the speed v with which the particles enter the cyclotron. (Express your answer in terms of V, m, and q.)

b) Find the radius r of the circular path followed by the particles. The magnitude of the magnetic field is B. (Express your answer in terms of v, m, B, and q.)

c) Find the period of revolution T for the particles. (Express your answer in terms of m, B, and q.)

d) Find the angular frequency ω of the particles. (Express your answer in terms of m, B, and q.)

e) Your goal is to accelerate the particles to kinetic energy K. What minimum radius R of the cyclotron is required? (Express your answer in terms of m, q, B, and K.)

2.4 A 40-turn, 4.0-cm-diameter coil with R = 0.40Ω surrounds a 3.0-cm-diameter solenoid. The solenoid is 20 cm long and has 200 turns. The 60Hz current through the solenoid is I = I0 sin(2πft). What is I0 if the maximum induced current in the coil is 0.20A? 2.5 The figure shows the interference pattern on a screen 1.0 m behind an 870 line/mm diffraction grating. What is the wavelength of the light?


4


3.1 A 90μF capacitor that had been charged to 30V is discharged through a resistor. The figure shows the capacitor voltage as a function of time. What is the value of the resistance?

3.2 The aurora is caused when electrons and protons, moving in the earth's magnetic field of ≈ 5×10-5 T, collide with molecules of the atmosphere and cause them to glow. a) What is the radius of the cyclotron orbit for an electron with speed 1.0 × 106 m/s? b) What is the radius of the cyclotron orbit for a proton with speed 5.0 × 104 m/s? 3.3 The wings of some beetles have closely spaced parallel lines of melanin, causing the wing to act as a reflection grating. Suppose sunlight shines straight onto a beetle wing. If the melanin lines on the wing are spaced 2.8 μm apart, what is the first-order diffraction angle for green light (λ = 550 nm)? Measure 4: Understand major issues and problems facing modern science and


4.1 Energy experts tell us to replace regular incandescent lightbulbs with compact fluorescent bulbs, but it seems hard to justify spending $15 on a lightbulb. A 60W incandescent bulb costs 50 cents. and has a lifetime of 1000 hours. A 15 W compact fluorescent bulb produces the same amount of light as a 60W incandescent bulb and is intended as a replacement. It costs $15 and has a lifetime of 10,000 hours. Compare the life-cycle costs of 60W incandescent bulbs to 15W compact fluorescent bulbs. The life-cycle cost of an object is the cost of purchasing it plus the cost of fueling and maintaining it over its useful life. Which is the cheaper source of light and which the more expensive? Assume that electricity costs 0.10 dollars/kWh. 4.2 One possible concern with MRI (magnetic resonance imaging) is turning the magnetic field on or off too quickly. Bodily fluids are conductors, and a changing magnetic field could cause electric currents to flow through the patient. Suppose a typical patient has a maximum cross-section area of 6.7×10−2 m2. What is the smallest time interval in which a 5.6T magnetic field can be turned on or off if the induced emf around the patient's body must be kept to less than 0.12V?


5

4.3 On average, each person in the industrialized world is responsible for the emission of 10,000 kg of carbon dioxide CO2 every year. This includes CO2 that you generate directly, by burning fossil fuels to operate your car or your furnace, as well as CO2 generated on your behalf by electric generating stations and manufacturing plants. CO2 is a greenhouse gas that contributes to global warming. If you were to store your yearly CO2 emissions in a cube at STP, how long would each edge of the cube be? 4.4 A typical nuclear reactor generates 1000MW (1000 MJ/s) of electrical energy. In doing so, it produces 2000MW of "waste heat" that must be removed from the reactor to keep it from melting down. Many reactors are sited next to large bodies of water so that they can use the water for cooling. Consider a reactor where the intake water is at 18 ºC. State regulations limit the temperature of the output water to 30ºC so as not to harm aquatic organisms. How many liters of cooling water have to be pumped through the reactor each minute? 4.5 A typical coal-fired power plant burns 350 metric tons of coal every hour to generate 750MW of electricity. 1 metric ton = 1000 kg. The density of coal is 1500 kg/m3 and its heat of combustion is 28MJ/kg. Assume that all heat is transferred from the fuel to the boiler and that all the work done in spinning the turbine is transformed into electrical energy. a) Suppose the coal is piled up in a 9.00m × 11.0m room. How tall must the pile be to operate the plant

for one day? b) What is the power plant's thermal efficiency? Measure 5: Demonstrate knowledge in one area of science, including understanding its

basic principles, laws, and theories. 5.1 Two 5.0g point charges on 1.0-m-long threads repel each other after being charged to +100 nC, as shown in the figure. What is the angle θ? You can assume that θ is a small angle. 5.2 A -2.0nC charge and a 2.0nC charge are located on the x-axis at x = -1.0cm and x = +1.0cm, respectively. a) At what position or positions on the x -axis is the electric field zero? b) At what position or positions on the x -axis is the electric potential zero? 5.3 What power is dissipated by the 2Ω resistor in the figure?


6

5.4 The Hubble Space Telescope has a mirror diameter of 2.4 m. Suppose the telescope is used to photograph stars near the center of our galaxy, 30,000 light years away, using red light with a wavelength of 650 nm. a) What's the distance (in km) between two stars that are marginally resolved? The resolution of a

reflecting telescope is calculated exactly the same as for a refracting telescope. b) For comparison, what is this distance as a multiple of the distance of Jupiter from the sun? 5.5 A monatomic gas follows the process 1→2→3 shown in the figure. a) How much heat is needed for process 1→2? b) How much heat is needed for process 2→3?


1

PHYS 1610 – Engineering Physics II Fall 2011 Instructor R Mode of Assessment: Assignment (MasteringPhysics)


1.2 70.7 77.1 89.10 1.3 78.3 96.5 98.75

2 2.1 80.3 92.2 95.95 2.2 74.5 72.4 80.51 2.3 85.4 75.7 99.54

3 3.1 82.2 93.7 96.46 4 4.1 79.0 95.6 96.00

4.2 72.0 85.5 93.45 4.3 81.5 94.8 96.00

5 5.1 75.2 86.3 86.96 5.2 61.1 59.2 78.60 5.3 77.1 92.5 95.01

Average 77.3 85.5 92.40


2

PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 A plastic rod that has been charged to -18 nC touches a metal sphere. Afterward, the rod's charge is -9.0 nC. a) What kind of charged particle was transferred between the rod and the sphere, and in which direction?

That is, did it move from the rod to the sphere or from the sphere to the rod? b) How many charged particles were transferred? 1.2 The two parallel plates in the figure are 2.0 cm apart and the electric field strength between them is 2.00×104 N/C. An electron is launched at a 45° angle from the positive plate. What is the maximum initial speed v0 the electron can have without hitting the negative plate? 1.3 The figure shows four sides of a 3.0 cm × 3.0 cm × 3.0 cm cube. a) What is the electric flux Ф1 through side 1? b) What is the electric flux Ф2 through side 2? c) What is the electric flux Ф3 through side 3? d) What is the electric flux Ф4 through side 4? e) What is the net flux through these four sides? Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 2.1 Two small plastic spheres each have a mass of 1.6g and a charge of -53.0 nC . They are placed 2.5cm apart (center to center). a) What is the magnitude of the electric force on each sphere? b) By what factor is the electric force on a sphere larger than its weight? 2.2 Two 9.0-cm-diameter charged disks face each other, 24 cm apart. Both disks are charged to – 80 nC. a) What is the electric field strength at the midpoint between the two

disks? b) What is the electric field strength a point on the axis 5.0 cm from one

disk between them?


3

2.3 The cube in the figure contains negative charge. The electric field is constant over each face of the cube. a) Does the missing electric field vector on the front face point in or out? b) What strength must this field exceed? Measure 3: Demonstrate an ability to conduct, and interpret the results of experiments

aimed at better understanding natural phenomena. 3.1 Air "breaks down" when the electric field strength reaches 3×106 N/C, causing a spark. A parallel-plate capacitor is made from two 4.0-cm-diameter disks. How many electrons must be transferred from one disk to the other to create a spark between the disks? 3.2 The aurora is caused when electrons and protons, moving in the earth's magnetic field of ≈ 5×10-5 T, collide with molecules of the atmosphere and cause them to glow. a) What is the radius of the cyclotron orbit for an electron with speed 1.0 × 106 m/s? b) What is the radius of the cyclotron orbit for a proton with speed 5.0 × 104 m/s? 3.3 The wings of some beetles have closely spaced parallel lines of melanin, causing the wing to act as a reflection grating. Suppose sunlight shines straight onto a beetle wing. If the melanin lines on the wing are spaced 2.8 μm apart, what is the first-order diffraction angle for green light (λ = 550 nm)? Measure 4: Understand major issues and problems facing modern science and


4.1 The electric field at a point in space is E = (500 i + 700 j) N/C. a) What is the x-component of the electric force on a proton at this point? b) What is the y-component of the electric force on a proton at this point? c) What is the x-component of the electric force on an electron at this point? d) What is the y-component of the electric force on a electron at this point? e) What is the magnitude of the proton's acceleration? f) What is the magnitude of the electron's acceleration? 4.2 An electron in a uniform electric field increases its speed from 2.1×107 m/s to 3.9×107 m/s over a distance of 1.8cm. What is the electric field strength? 4.3 The electric flux through the surface shown in the figure is 11N·m2/C. What is the electric field strength?


4


5.1 The identical small spheres shown in the figure are charged to +100 nC and -100 nC. They hang as shown in a 1.00×105 N/C electric field. What is the mass of each sphere? 5.2 A proton orbits a long charged wire, making 1.90 × 106 revolutions per second. The radius of the orbit is 1.50 cm. What is the wire's linear charge density? 5.3 A hollow metal sphere has inner radius a and outer radius b. The hollow sphere has charge +2Q. A point charge +Q sits at the center of the hollow sphere. a) Determine the magnitude of the electric field in the region r ≤ a. b) Determine the magnitude of the electric field in the region a< r < b. c) Determine the magnitude of the electric field in the region r ≥ b. d) How much charge is on the inside surface of the hollow sphere? e) How much charge is on the exterior surface?

NO-PHYS1610-Spring 2012

1

PHYS 1610 – Engineering Physics II Spring 2012 Instructors N and O Mode of Assessment: Assignment (MasteringPhysics)

Measures Problems % Complete % Average Score %

National Score

Instructor N

Instructor O

Instructor N

Instructor O

1 1.1 83.9 60.2 92.6 87.2 91.92 1.2 89.3 98 95.47 1.3 87.1 90.3 94.89 1.4 87.5 94.9 97.80 1.5 84.8 72.6 93.2 82.5 92.78

2 2.1 86.2 84.4 90.9 89.3 94.48 2.2 87.9 76.9 99 83.4 97.79 2.3 83 84.4 94.1 90.3 95.23 2.4 78.6 88.1 87.88 2.5 79.9 96.6 96.91

3 3.1 87.1 60.8 99.5 92.2 92.78 3.2 87.9 97 97.49 3.3 87.1 91.8 86.56 3.4 82.1 76.3 91.3 72.3 91.83 3.5 83.9 85.5 95.5 92.6 97.68

3.6

(Lab) 94.3 92.3

4 4.1 87.1 58.6 97.9 92.6 94.89 4.2 80.8 55.9 96.1 90.7 95.15 4.3 65.6 92.5 92.42 4.4 89.3 84.9 99 81.3 99.92 4.5 80.4 95 96.77

5 5.1 79.9 55.9 95 81.3 88.76 5.2 83.5 90 91.25 5.3 92.9 89.8 98.6 84.2 99.63 5.4 81.3 77.4 89 76.0 92.72

Average 84.0 73.1 94.4 85.9 94.29


2

PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 A 20-cm-diameter cylinder that is 40 cm long contains 50 g of oxygen gas at 20 ºC. a) How many moles of oxygen are in the cylinder? b) How many oxygen molecules are in the cylinder? c) What is the number density of the oxygen? d) What is the reading of a pressure gauge attached to the tank? 1.2 Light from a sodium lamp (λ = 589nm) illuminates two narrow slits. The fringe spacing on a screen 150cm behind the slits is 4.0 mm. What is the spacing (in mm) between the two slits? 1.3 A plastic rod that has been charged to -18 nC touches a metal sphere. Afterward, the rod's charge is -9.0 nC. a) What kind of charged particle was transferred between the rod and the sphere, and in which direction?

That is, did it move from the rod to the sphere or from the sphere to the rod? b) How many charged particles were transferred? 1.4 What is the net electric force on charge A in the figure? 1.5 In a classical model of the hydrogen atom, the electron orbits the proton in a circular orbit of radius 0.053nm. What is the orbital frequency? The proton is so much more massive than the electron that you can assume the proton is at rest. Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 2.1 a) What is the magnitude of the force F on the 1.0 nC charge in the figure ? b) What is the direction of the force F on the 1.0 nC charge in the figure?


3

2.2 Charge Q is uniformly distributed along a thin, flexible rod of length L. The rod is then bent into the semicircle shown in the figure. a) Find an expression for the electric field E at the center of the semicircle. b) Evaluate the field strength if L = 10cm and Q = 30nC. 2.3 A proton moves in the magnetic field B = 0.50i T with a speed of 1.0 × 107m/s in the directions shown in the figure. For each, what is magnetic force F on the proton? a) Express vector F in the form Fx, Fy, Fz, where the x, y, and z components are separated by commas. b) Express vector F in the form Fx, Fy, Fz, where the x, y, and z components are separated by commas. 2.4 A 40-turn, 4.0-cm-diameter coil with R = 0.40Ω surrounds a 3.0-cm-diameter solenoid. The solenoid is 20 cm long and has 200 turns. The 60Hz current through the solenoid is I = Io sin(2πft). What is Io if the maximum induced current in the coil is 0.20A? 2.5 Particle accelerators are used to create well-controlled beams of high-energy particles. Such beams have many uses, both in research and industry. One common type of accelerator is the cyclotron, as shown in the figure. In a cyclotron, a magnetic field confines charged particles to circular paths while an oscillating electric field accelerates them. It is useful to understand the details of this process. Consider a cyclotron in which a beam of particles of positive charge q and mass m is moving along a circular path restricted by the magnetic field B (which is perpendicular to the velocity of the particles).


4

a) Before entering the cyclotron, the particles are accelerated by a potential difference V. Find the speed v with which the particles enter the cyclotron. (Express your answer in terms of V, m, and q.)

b) Find the radius r of the circular path followed by the particles. The magnitude of the magnetic field is B. (Express your answer in terms of v, m, B, and q.)

c) Find the period of revolution T for the particles. (Express your answer in terms of m, B, and q.) d) Find the angular frequency ω of the particles. (Express your answer in terms of m, B, and q.) e) Your goal is to accelerate the particles to kinetic energy K. What minimum radius R of the cyclotron

is required? (Express your answer in terms of m, q, B, and K.) Measure 3: Demonstrate an ability to conduct, and interpret the results of experiments

aimed at better understanding natural phenomena. 3.1 The solar corona is a very hot atmosphere surrounding the visible surface of the sun. X-ray emissions from the corona show that its temperature is about 2×106 K. The gas pressure in the corona is about 0.03 Pa. Estimate the number density of particles in the solar corona. 3.2 The wings of some beetles have closely spaced parallel lines of melanin, causing the wing to act as a reflection grating. Suppose sunlight shines straight onto a beetle wing. If the melanin lines on the wing are spaced 2.8 μm apart, what is the first-order diffraction angle for green light (λ = 550 nm)? 3.3 The figure is an edge view of three charged metal electrodes. Draw a graph of V versus x over the region 0 x 3 cm. Hint: Assume that V = 0 V at x = 0 cm. 3.4 A 90μF capacitor that had been charged to 30V is discharged through a resistor. The figure shows the capacitor voltage as a function of time. What is the value of the resistance?

3.5 The aurora is caused when electrons and protons, moving in the earth's magnetic field of ≈ 5×10-5 T, collide with molecules of the atmosphere and cause them to glow. a) What is the radius of the cyclotron orbit for an electron with speed 1.0 × 106 m/s? b) What is the radius of the cyclotron orbit for a proton with speed 5.0 × 104 m/s?


5

3.6 Lab: Series & Parallel Resistors The experiment on Series and Parallel DC circuits conducted in the undergraduate laboratory consisted of the following tasks given below. Students explored how voltages across resistors and currents going through resistors behaved under various combinations of resistors in series and parallel. The students also built circuits and verified the voltages, currents, and resistances using a multimeter. Part I: Series & Parallel Combinations with Two and Three Resistors (40 pts total) Calculate the total resistance of each circuit, the voltage across each resistor and the current going through each resistor for the given circuits. After you have theoretically determined the resistances, voltages and currents, assemble each circuit using the two 100Ω resistors and the 200Ω resistor your group has been provided, and verify the voltages and currents using a multimeter. Part II: Series and Parallel Combinations using Four Resistors (60 pts total) Your group will use the schematic below (also located on the Data Sheet) to design a circuit that will meet the three (3) criteria your group has been assigned. Your TA will assign your group one of the 12 sets of conditions. Your group must use two 100Ω resistors, one 200Ω resistor, and a 50Ω resistor, and only these values, to build your circuit by assigning them to the correct positions in the circuit. When you are confident that your group has designed your circuit properly and your group has calculated the current that will pass through the 50Ω resistor, your TA will come to your station and provide your group with a 50Ω resistor and test your group’s knowledge of the circuit. Measure 4: Understand major issues and problems facing modern science and


4.1 On average, each person in the industrialized world is responsible for the emission of 10,000 kg of carbon dioxide CO2 every year. This includes CO2 that you generate directly, by burning fossil fuels to operate your car or your furnace, as well as CO2 generated on your behalf by electric generating stations and manufacturing plants. CO2 is a greenhouse gas that contributes to global warming. If you were to store your yearly CO2 emissions in a cube at STP, how long would each edge of the cube be? 4.2 A typical nuclear reactor generates 1000MW (1000 MJ/s) of electrical energy. In doing so, it produces 2000MW of "waste heat" that must be removed from the reactor to keep it from melting down. Many reactors are sited next to large bodies of water so that they can use the water for cooling. Consider a reactor where the intake water is at 18 ºC. State regulations limit the temperature of the output water to 30ºC so as not to harm aquatic organisms. How many liters of cooling water have to be pumped through the reactor each minute? 4.3 A typical coal-fired power plant burns 350 metric tons of coal every hour to generate 750MW of electricity. 1 metric ton = 1000 kg. The density of coal is 1500 kg/m3 and its heat of combustion is 28MJ/kg. Assume that all heat is transferred from the fuel to the boiler and that all the work done in spinning the turbine is transformed into electrical energy. a) Suppose the coal is piled up in a 9.00m × 11.0m room. How tall must the pile be to operate the plant

for one day? b) What is the power plant's thermal efficiency?


6

4.4 Energy experts tell us to replace regular incandescent lightbulbs with compact fluorescent bulbs, but it seems hard to justify spending $15 on a lightbulb. A 60W incandescent bulb costs 50 cents. and has a lifetime of 1000 hours. A 15 W compact fluorescent bulb produces the same amount of light as a 60W incandescent bulb and is intended as a replacement. It costs $15 and has a lifetime of 10,000 hours. Compare the life-cycle costs of 60W incandescent bulbs to 15W compact fluorescent bulbs. The life-cycle cost of an object is the cost of purchasing it plus the cost of fueling and maintaining it over its useful life. Which is the cheaper source of light and which the more expensive? Assume that electricity costs 0.10 dollars/kWh. 4.5 One possible concern with MRI (magnetic resonance imaging) is turning the magnetic field on or off too quickly. Bodily fluids are conductors, and a changing magnetic field could cause electric currents to flow through the patient. Suppose a typical patient has a maximum cross-section area of 6.7×10−2 m2. What is the smallest time interval in which a 5.6T magnetic field can be turned on or off if the induced emf around the patient's body must be kept to less than 0.12V? Measure 5: Demonstrate knowledge in one area of science, including understanding its

basic principles, laws, and theories. 5.1 A monatomic gas follows the process 1→2→3shown in the figure. a) How much heat is needed for process 1→2? b) How much heat is needed for process 2→3? 5.2 A spherically symmetric charge distribution produces the electric field E = (4900 r2) er N/C, where r is in m. a) What is the electric field strength at r = 25.0 cm? b) What is the electric flux through a 38.0-cm-diameter spherical surface that is concentric with the

charge distribution? c) How much charge is inside this 38.0-cm-diameter spherical surface? 5.3 A -2.0nC charge and a 2.0nC charge are located on the x-axis at x = -1.0cm and x = +1.0cm, respectively. a) At what position or positions on the x -axis is the electric field zero? b) At what position or positions on the x -axis is the electric potential zero? 5.4 What power is dissipated by the 2Ω resistor in the figure?

PHYS 1607

Honors Physics I

M-PHYS1607-Fall 2011

1

PHYS 1607 – Honors Physics I Fall 2011 Instructor M Mode of Assessment: Tests

Measures Problems % Average Score 1 1.1 40 1 1.2 43 1 1.3 67 1 1.4 64 2 2.1 91 2 2.2 34 2 2.3 66 2 2.4 67 3 3.1 37 3 3.2 44 3 3.3 94 3 3.4 40 4 4.1 84 4 4.2 81 4 4.3 59 5 5.1 31 5 5.2 79 5 5.3 87 5 5.4 76 5 5.5 84

Average 63.4


2

PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 Two cars travel along a level highway. It is observed that the distance between the cars is

increasing. Which one of the following statements concerning this situation is necessarily true?

a. The velocity of each car is increasing. b. At least once of the cars has a non-zero acceleration. c. The leading car has the greater acceleration. d. The tailing car has the smaller acceleration. e. Both cars could be accelerating at the same time. 1.2 A ball is fired at an angle of 45°, the angle that yields the maximum range in the absence of

air resistance. What is the ratio of the ball's maximum height to its range? a. 1.0 b. 0.75 c. 0.67 d. 0.50 e. 0.25 f. None of these 1.3 What would you experience when swimming in water in an orbiting space habitat where

simulated gravity is 0.5g? Would you float in the water as you do on earth? If so, would you float

a. deeper b. shallower c. the same 1.4 Planets A and B are uniform solid spheres that rotate at a constant speed about axes through

their centers. Although B has twice the mass and three times the radius of A, each planet has the same rotational kinetic energy. What is the ratio B/A of their angular speeds?

a. 0.055 b. 0.093 c. 0.165 d. 0.191 e. 0.236


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Measure 2: Understand the scientific method and demonstrate an ability to apply it across a variety of situations.

2.1 A 35-kg girl is standing near and to the left of a 43-kg boy on the frictionless surface of a

frozen pond. The boy tosses a 0.75-kg ice ball to the girl with a horizontal speed of 6.2 m/s. What are the velocities of the boy and the girl immediately after the girl catches the ice ball?

girl boy a. 0.81 m/s, left 0.67 m/s, right b. 0.17 m/s, left 0.14 m/s, left c. 0.18 m/s, right 0.13 m/s, left d. 0.42 m/s, left 0.49 m/s, right e. 0.13 m/s, left 0.11 m/s, right 2.2 Consider a satellite in a circular orbit around the Earth. If it were at an altitude equal to

twice the radius of the Earth, 2RE, how would its speed v be related to the Earth's radius RE and the magnitude g of the acceleration due to gravity on the Earth's surface?

a. v2 = gRE/9 b. v2 = 2gRE

c. v2 = gRE/3 d. v2 = gRE/4 e. v2 = gRE/2 2.3 A solid cylinder with a mass m and radius r is mounted so that it can be rotated about an

axis that passes through the center of both ends. At what angular speed must the cylinder rotate to have the same total kinetic energy that it would have if it were moving horizontally with a speed v without rotation?

a. ω = v/r b. ω = v2/r2 c. ω = v/2r d. ω = v/r (2)0.5 e. ω = v2/2r 2.4 A massless frame in the shape of a square with 2-m sides has a 1-kg ball at each corner.

What is the moment of inertia of the four balls about an axis through the corner marked 0 and perpendicular to the plane of the paper?

a. 4 kg · m2 b. 8 kg · m2 c. 10 kg · m2 d. 12 kg · m2 e. 16 kg · m2 f. None of these


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The next two questions pertain to this situation:

Two blocks rest on a horizontal frictionless surface as shown. The surface between the top and bottom blocks is roughened so that there is no slipping between the two blocks. A 30-N force is applied to the bottom block as shown in the figure.

3.1 What is the force of static friction between the top and bottom blocks? a. 0 b. 10 N c. 20 N d. 25 N e. 30 N f. None of these

3.2 What is the minimum coefficient of static friction necessary to keep the top block from slipping on the bottom block?

a. 0.05 b. 0.10 c. 0.20 d. 0.30 e. 0.40 f. None of these 3.3 In an experiment with a block of wood on an inclined plane,

with dimensions shown in the figure, the following observations are made:

If the block is placed on the inclined plane, it remains there at rest.

If the block is given a small push, it will accelerate toward the bottom of the incline without any further pushing.

Which is the best conclusion that can be drawn from these observations? a. The coefficient of kinetic friction must be negative. b. Both coefficients of friction must be less than 0.25. c. Both coefficients of friction must be greater than 0.25. d. The coefficient of static friction must be less than the coefficient of kinetic friction. e. The coefficient of static friction is greater than 0.25 while the coefficient of kinetic

friction is less than 0.25.

3.4 A 50-kg toboggan is coasting on level snow. As it passes beneath a bridge, a 20-kg parcel is dropped straight down and lands in the toboggan. If (KE)1 is the original kinetic energy of the toboggan and (KE)2 is the kinetic energy after the parcel has been added, what is the ratio (KE)2/(KE)1.

a. 0.36 b. 0.60 c. 0.71 d. 1.00 e. 1.67 f. None of these


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4.1 After a moving van drives onto a river ferry, the ferry sinks 0.0367 m. The length and

width of the ferry are 15.24 m and 6.10 m, respectfully. Determine the weight of the moving van.

a. 6.09 x 103 N b. 1.00 x 104 N c. 3.34 x 104 N d. 5.11 x 104 N e. 6.68 x 104 N f. None of these 4.2 In an amusement park ride, a small child stands against the wall of a cylindrical room that

is then made to rotate. The floor drops downward and the child remains pinned against the wall. If the radius of the device is 2.15 m and the relevant coefficient of friction between the child and the wall is 0.400, with what minimum speed is the child moving if he is to remain pinned against the wall?

a. 7.26 m/s b. 3.93 m/s c. 12.1 m/s d. 5.18 m/s e. 9.80 m/s f. None of these 4.3 Two boxes are connected to each other as shown. The system is released from rest and the

1.00-kg box falls through a distance of 1.00 m. The surface of the table is frictionless. What is the kinetic energy of box B just before it reaches the floor?

a. 2.45 J b. 4.90 J c. 9.80 J d. 29.4 J e. 39.2 J f. None of these


6


The next two questions relate to this situation.

A small car of mass M travels along a straight, horizontal track. As suggested in the figure, the track then bends into a vertical circle of radius R

5.1 What is the minimum acceleration that the car must have at the top of the track if it is to

remain in contact with the track? a. 4.9 m/s2, downward b. 4.9 m/s2, upward c. 9.8 m/s2, upward d. 9.8 m/s2, downward e. 19.6 m/s2, upward f. None of these 5.2 Which expression determines the minimum speed that the car must have at the top of the

track if it is to remain in contact with the track? a. v = MgR b. v = 2gR c. v2 = 2gR d. v2 = gR e. v = gR 5.3 Two sleds are hooked together in tandem as shown in the figure. The front sled is twice as

massive as the rear sled. The sleds are pulled along a frictionless surface by an applied force F. The tension in the rope between the sleds is T. Determine the ratio of the magnitudes of the two forces, T/F. a. 0.25

b. 0.33 c. 0.50 d. 0.67 e. 2.0 f. None of these


7

5.4 A 10-kg block is pushed against a vertical wall by a horizontal force of 100 N as shown in the figure. The coefficient of static friction, µs, between the block and the wall is 0.60; and the coefficient of kinetic friction, µk, is 0.40. Which one of the following statements is true if the block is initially at rest?

a. The total force exerted on the block by the wall is horizontally directed. b. The block slides down the wall with an acceleration of magnitude 3.8 m/s2. c. The block will slide down the wall because the force of static friction can be no

larger than 60 N. d. The block will remain at rest because the coefficient of static friction is greater than the

coefficient of kinetic friction. e. The block will slide down the wall because the coefficient of kinetic friction is less

than the coefficient of static friction. 5.5 A woman stands on the edge of a cliff and throws a stone vertically downward with an

initial speed of 10 m/s. The instant before the stone hits the ground below, it has 450 J of kinetic energy. If she were to throw the stone horizontally outward from the cliff with the same initial speed of 10 m/s, how much kinetic energy would it have just before it hits the ground?

a. 50 J b. 100 J c. 450 J d. 800 J e. 950 J

PHYS 1617

Honors Physics II

M-PHYS1617-Spring 2012

1

PHYS 1617 – Honors Physics II Spring 2012 Instructor M Mode of Assessment: Tests

Measures Problems % Average Score 1 1.1 61 1 1.2 84 1 1.3 58 2 2.1 91 2 2.2 67 2 2.3 77 2 2.4 74 3 3.1 100 3 3.2 91 3 3.3 91 3 3.4 86 3 3.5 28 4 4.1 79 4 4.2 100 4 4.3 100 4 4.4 95 5 5.1 88 5 5.2 95 5 5.3 86 5 5.4 95 5 5.5 93

Average 82.8


2

PROBLEMS: Measure 1: Articulate the philosophical and historical foundations of modern science. 1.1 An unmagnetized metal sphere hangs by a thread. When the north pole of a bar magnet is brought

near, the sphere is strongly attracted to the magnet. Then the magnet is reversed and its south pole is brought near the sphere. How does the sphere respond?

a. It is strongly attracted to the magnet. b. It is weakly attracted to the magnet. c. It does not respond. d. It is weakly repelled by the magnet. e. It is strongly repelled by the magnet.

1.2 An electron in the beam of a TV picture tube is accelerated by a potential difference of 2.00 kV. Then it passes through a region of transverse magnetic field, where it moves in a circular arc with radius 0.180 m. What is the magnitude of the field?

a. 1.20 x 10-5 T b. 2.65 x 10-5 T c. 2.65 x 10-4 T d. 8.34 x 10-4 T e. 9.24 x 10-4 T

1.3 Light of wavelength 500 nm in air enters a glass block with index of refraction, n = 1.5. When the light enters the block, which of the following properties of the light will not change?

a. The speed of the light b. The frequency of light c. The wavelength of the light Measure 2: Understand the scientific method and demonstrate an ability to apply it

across a variety of situations. 2.1 An ice-cube tray of negligible mass contains 0.350 kg of water at 18.0C. How much heat must be

removed to cool the water to 0.00C and freeze it? a. 34.2 kJ b. 90.5 kJ c. 104 kJ d. 130 kJ e. 143 kJ

2.2 In a gas at STP, what is the length of the side of a cube that contains a number of molecules equal to the population of the earth (about 6 billion people)?

a. 0.61 m b. 2.6 m c. 3.9 m d. 6.1 m e. 22.4 m


3

2.3 A gas undergoes two processes. In the first, the volume remains constant at 0.200 m3 and the pressure increases from 2.00 x 105 Pa to 5.00 x 105 Pa. The second process is a compression to a volume of 0.120 m3 at a constant pressure of 5.00 x 105 Pa. Find the total work done by the gas during both processes.

a. – 40 kJ b. – 16 kJ c. 0.0 kJ d. 16 kJ e. 40 kJ 2.4 An object is 50 cm from a diverging lens with a focal length of -20 cm. How far from the lens is the

image, and which side of the lens is it on? a. 14 cm, on the same side as the object b. 14 cm, on the opposite side from the object c. 30 cm, on the same side as the object d. 33 cm, on the same side as the object e. 33 cm, on the opposite side from the object Measure 3: Demonstrate an ability to conduct, and interpret the results of experiments

aimed at better understanding natural phenomena. The next three questions all use the same set up below: A 75-kg person holds out his arms so that his hands are 1.7 m apart. Typically, a person’s hand

makes up about 1.0% of his or her body weight. For round numbers, we shall assume that all the weight of each hand is due to the calcium in the bones, and we shall treat the hands as point charges. One mole of Ca contains 40.18 g and each atom has 20 protons and 20 electrons. Suppose that only 1.0% of the positive charges in each hand were unbalanced by negative charge.

3.1 How many Ca atoms does each hand contain? a. 1.12 x 1025 atoms b. 2.31 x 1025 atoms c. 6.02 x 1025 atoms d. 7.82 x 1025 atoms e. 9.13 x 1025 atoms 3.2 How many coulombs of unbalanced charge does each hand contain? a. 1.1 x 105 C b. 1.8 x 105 C c. 3.6 x 105 C d. 4.0 x 105 C e. 9.6 x 105 C 3.3 What force would the person’s arms have to exert on his hands to prevent them from flying off? a. 1.0 x 1020 N b. 4.0 x 1020 N c. 5.0 x 1020 N d. 1.6 x 1021 N e. 2.9 x 1021 N


4

3.4 What diameter must a copper wire have if its resistance is to be the same as that of an equal length of aluminum wire with diameter a = 3.26 mm? (al = 2.63 x 10-8 m, c = 1.72 x 10-8 m)

a. 2.14 mm b. 2.64 mm c. 3.26 mm d. 4.03 mm e. 6.93 mm 3.5 A stereo amplifier creates a 5.0 V potential difference across a speaker. To double the power output

of the speaker, the amplifier’s potential difference must be increased to a. 7.1 V b. 10 V c. 14 V d. 25 V e. 31 V



4.1 If the air temperature is the same as the temperature of your skin (~ 30C) your body cannot get rid

of heat by transferring it to the air. In that case, it gets rid of the heat by evaporating water (sweat). During bicycling, a typical 70-kg person’s body produces energy at a rate of about 500 W due to metabolism, 80% of which is converted to heat. How many kilograms of water must the person’s boy evaporate in an hour to get rid of this heat? The heat of vaporization of water at body temperature is 2.42 x 106 J/kg.

a. 0.01 kg b. 0.34 kg c. 0.60 kg d. 0.74 kg e. 4.32 kg The next three questions all use the same set up below:

The nuclei of large atoms, such as uranium, with 92 protons, can be modeled as spherically symmetric spheres of charge. The radius of the uranium nucleus is approximately 7.4 x 10-15 m.

4.2 What is the electric field this nucleus produces just outside its surface? a. 0 N/C b. 2.4 x 1021 N/C c. 3.1 x 1021 N/C d. 6.1 x 1021 N/C e. 1.2 x 1022 N/C 4.3 What magnitude of electric field does it produce at the distance of the electrons, which is about 1.0

x 10-10 m? a. 4.5 x 1012 N/C b. 1.3 x 1013 N/C c. 3.3 x 1013 N/C d. 7.2 x 1013 N/C e. 3.2 x 1015 N/C


5

4.4 The electrons can be modeled as forming a uniform shell of negative charge. What net electric field do they produce at the location of the nucleus?

0 N/C a. 2.4 x 1021 N/C b. 3.1 x 1021 N/C c. 6.1 x 1021 N/C d. 1.2 x 1022 N/C Measure 5: Demonstrate knowledge in one area of science, including understanding its

basic principles, laws, and theories. 5.1 How much work is needed to assemble an atomic nucleus containing three protons (such as

Be) if we model it as an equilateral triangle of side 2.00 x 10-15 m with a proton at each vertex? Assume the protons started from very far away.

a. 0 J b. 1.14 x 10-13 J c. 2.31 x 10-13 J d. 3.46 x 10-13 J e. 4.60 x 10-13 J 5.2 At a certain distance from a point charge, the potential and electric field magnitude due to

that charge are 4.98 V and 12.0 V/m respectively. Take V = 0 at infinity. What is the magnitude of the charge?

a. 0.07 nC b. 0.17 nC c. 0.23 nC d. 0.27 nC e. 0.42 nC The next three questions all use the same set up below: A 5.00 pF, parallel-plate, air-filled capacitor with circular plates is to be used in a circuit in

which it will be subjected to potentials of up to 1.00 x 102 V. The electric field between the plates is to be no greater than 1.00 x 104 N/C.

5.3 Whatshouldbetheradiusofeachplate? a. 4.2mm b. 5.7mm c. 2.1cm d. 4.2cm e. 5.7cm


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5.4 Whatshouldbethespacingofthecapacitor? a. 1.0cm b. 1.9cm c. 2.2cm d. 3.1cm e. 5.0cm 5.5 Whatisthemaximumchargetheyshouldhold? a. 63pC b. 125pC c. 250pC d. 500pC

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