Inertia Unit Student Design Cover Page - Web viewSkim through Chapter 4 of your textbook ... 4.3 . Galileo argued that ... Stack four washers one on top of the other so that you form

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Inertia Unit Student Design Cover Page(See directions on page 19)

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Inertia Unit Front Page

At the end of this unit I will be able to:q Explain the history behind Newton’s first law of motion. q Use the difference between mass and weight to explain why

weight is a force.q Demonstrate drawing free body diagrams and calculating net

force. q Apply the law of inertia to real-world examples to predict a situation’s outcome.q Identify and describe the various forces acting on an object at equilibrium.

Roots, prefixes, and suffixes I will understand and recognize are:q Kilo-, equ-, -gram, in-

The terms I will clearly define are:q Equilibrium, Force, Friction, Inertia, Kilogram, Mass, Net force, Newton, Normal force,

Tension, Volume, Weight

The assignments I will have completed by the end of the unit are:q Textbook Outlineq Physics Equation Sheetq Newton’s Law of Inertia Notesq Think & Explain Questionsq Inertia Olympicsq Force Notesq Concept Development Practiceq ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________q ____________________________________________

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Textbook Outline

Skim through Chapter 4 of your textbook (pages 43-56). For each section below, fill in the missing blanks.

4.1

Aristotle believed that there were two types of motion:

o

o

It was thought that motion was only possible because of an outside

4.2

Nicolaus Copernicus’s extremely controversial idea was that _________________________________

move around _________________________________.

4.3

Galileo argued that if friction is absent, a moving object would

He proved his ideas using balls rolling down incline planes.

A force is any

Friction is the name given to the force that acts

Inertia is the tendency of a moving body to

4.4

Isaac Newton developed laws of motion that are still accepted today.

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Newton’s first law is usually called

o Every object continues in a state of rest, or of motion in a straight line at constant

speed, unless it is compelled to change that state by forces exerted on it.

Textbook Pre-reading Outline

4.5

The amount of an object has depends on its

What mass isn’t:

o Volume – volume is a measure of

o Weight – weight is the force

Mass and weight are to each other but not

equal.

Mass is the quantity of and a

measure of the inertia of an object.

The unit for force is the (N). 1 kg = N

4.6

Forces are vectors that can combine and sometimes cancel each other out.

Net force is the combination of

4.7

The support force is also called the

Equilibrium is when the net force on an object is

Tension is the force in a rope or string when an object hangs from it.

4.8

Forces (including tension) can be added as vectors.

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For a pair of ropes/scales/wires that are supporting a load, the greater the angle from the

vertical,

4.9

When you flip a coin in a high-speed air plane, it behaves as if the plane were at rest. This is

an example of in action!

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Physics Quantities Sheet

QuantityVariable used in

equations

Unit used to measure the

quantity

Symbol/info about unit

Misc.

Distance/displacement d Usually meter m

Velocity/speed vUsually meters per

secondm/s

Acceleration aUsually meters per second per second

m/s2

Time t Usually seconds s

Mass

Volume

Weight

Force

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Think & Explain Questions

1. When a junked car is crushed into a compact cube, which of the following changes?

a. Mass

b. Volume

c. Weight

d. Inertia

2. When you compress a sponge, which quantities change?

a. Mass

b. Volume

c. Weight

d. Inertia

3. Suppose you place a ball in the middle of a wagon that is at rest and then abruptly pull the

wagon forward. Describe in at least one complete sentence the motion of the ball relative to:

a. The ground:

b. The wagon:

4. If an elephant were chasing you, its enormous mass would be very threatening. But if you

zigzagged, the elephant’s mass would be to your advantage. Why? Use complete sentences.

5. Many automobile passengers suffer neck injuries when struck by cars from behind. How does

Netwon’s law of inertia apply here? Use complete sentences.

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6.

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Newton’s Law of Inertia Notes

What did Aristotle believe about motion?

Aristotle distinguished between two types of motion:1. __________________________________________2. __________________________________________

Motion begins, ends, and changes according to __________________________________________________________________________________________________________________

What did Galileo believe about motion?

Galileo formulated the concept of __________________________ and acceleration due to gravity.

Galileo also supported the idea that the earth (and other planets)___________________________________________________________________________

What did Newton believe about motion?

Sir Isaac Newton developed ______________________________________________Newton’s first law is also known as __________________________________________

What is inertia?

Inertia is _____________________________________________________________________________________________________________________________________________________________

Objects at rest _____________________________________________________ Objects in motion _________________________________________________ Unless ___________________________________________________________________

What is mass?

Mass is how much ______________________________ is in an object.It is also a measure of inertia or ___________________________________________________________________________________________________________________________________Mass is measured in ______________________________________________

Are mass and volume the same thing?

___________! Volume is a measure of ______________________ and has units of ________________________________________________________________________________

Are mass and weight the same thing?

______________!Weight is a measure of __________________________________________________________Since inertia is a property of mass, not weight, it is just as hard to start or stop an object moving on ______________________________________________________

How is weight measured?

Weight is measured in ______________________________ (N). Weight is a measurement of gravity’s pull on a ____________________. w = mg 1 kg = _______________ N

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Concept Development 4-1

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Inertia Olympics!

STATION A: Wacky Washers

Stack four washers one on top of the other so that you form a tower of washers. Place the stack of washers on your textbook or floor so that you a smooth, slick surface. Aim one washer at the bottom of the stack of four washers and give it a good flick with your finger or hand.

Goal:

Explain what’s happening in terms of Newton’s first law.

STATION B: Tricky Tricks

Place a circle of paper (with string attached) to the top of a clothespin. Stack a penny on top of the circle of paper. Quickly pull the string to move the circle of paper off the clothespin.

Goal:


Once you’ve mastered station B, try the trick again. This time, instead of using a clothespin balance the paper circle and penny on your finger!

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Inertia Olympics!

STATION C: A Body in Motion

Can you drop a tennis ball on a target while you’re running past the target? Predict where you will need to release the ball in order to hit the target. Mark your prediction below:

Hold the tennis ball and do not let your elbow leave your side as you run from the starting line to the target. As you are running, drop the ball and try to hit the target. You are dropping the ball, NOT throwing it (otherwise you will change the intent of the experiment).


STATION D: HOOPS

Balance the hoop on the center of the mouth of the bottle. Next, balance the washer on the hoop aligning it with center of the mouth of the bottle. Pull the hoop fast forward or backward.

Goal:


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Inertia Olympics!

STATION E: CATCHING PENNIES

Place a penny on your bent elbow. Quickly move your elbow back and try to catch the penny. Next, try two or more pennies. Keep trying and see how many you can catch at once!


STATION F: CUP CATCH

Place an index card on top of an empty cup. Position one penny on top of the index card. Quickly jerk the index card away.

Goal:


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Warm Up

Explain:

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Force Notes

Draw the normal force for both situations below:

Draw a “free body diagram” for the situation below:

A person horizontally pushes a wooden crate across the floor.

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Force Notes

What is force?

A force is any ______________________ or ________________________.There are many different types of forces including:

______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________ ______________________________________

What is the net force?The ______________________________________ of all forces acting on an object is called the ______________________________________________.

What is the normal force?

The normal force is a _________________________________ force that is ___________________________________ to the surface and is equal to the weight of the object.

Ex. For an object resting on a table, the table pushes up on the object just as much as the object pushes down on the table.

What is a “state of equilibrium”?

When the ______________________________________ on an object equals ______________, we say that the object is at equilibrium.

What is tension?When an object hangs from a cable/rope/string, the _______________ in the cable/rope/string are ______________________________________________________. This is a _____________________________ force.

How are forces added together?

Forces can be added as _________________________________.

Summary:

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Recognizing Forces

Net Force Help Sheet

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Type of Force Explanation

Weight (W) or Force of Gravity(Fgrav)

The force of gravity is the force at which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity which is directed "downward" towards the center of the earth. The force of gravity on earth is always equal to the weight of the object as found by the equation:Fgrav = m * g where g = 9.8 N/kg (on Earth)

Normal Force (Fnorm or FN)

The normal force is the support force exerted upon an object which is in contact with another stable object. For example, if a book is resting upon a surface, then the surface is exerting an upward force upon the book in order to support the weight of the book. On occasions, a normal force is exerted horizontally between two objects which are in contact with each other.

Spring (Fspring or Fs)

The spring force is exerted by a spring upon the objects connected to each of its two ends. Spring forces may result from either a compressed or a stretched spring. The magnitude of a spring force is dependent upon the elasticity of the spring (usually denoted by its spring constant k) and upon the amount of compression or stretch (x) of the spring from its equilibrium position. The general equation for spring force is Fspring = k * x

Sliding Friction Forces (Ffrict or Ff)

The frictional force is the force exerted by a surface as an object moves across it. The sliding friction force opposes the motion of the object. For example, if a book moves across the surface of a desk, then the desk exerts a frictional force in the opposite direction of its motion. The frictional force can often be calculated using the equation: Ffrict = μ * Fnorm

Air Resistance (Fair or R)

The air resistance is a special type of frictional force which acts upon objects as they travel through the air. The force of air resistance always opposes the motion of the object. This force will frequently be neglected due to its negligible magnitude. It is most noticeable for objects which travel at high speeds (e.g., a skydiver or a downhill skier) or for objects with large surface areas.

Tension (Ftens or T)

The tension is the force which is transmitted through a string, rope, wire or cable when it is pulled tight by forces acting from each end. The tensional force is directed along the wire and pulls equally on the objects on either end of the wire.

Applied Force(Fapp or Fa)

The applied force is the force which is applied to an object by a person or another object. If a person is pushing a desk across a room, then there is an applied force acting upon the object. The applied force is the force exerted on the desk by the person.

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Finding Individual Forces

Inertia, Mass, & Weight Review

1. Two bricks are resting on edge of the lab table. Shirley stands on her toes and spots the two bricks. She acquires an intense desire to know which of the two bricks are most massive. Since Shirley is vertically challenged, she is unable to reach high enough and lift the bricks; she can however reach high enough to give the bricks a push. Discuss how the process of pushing the bricks will allow Shirley to determine which of the two bricks is most massive. What difference will Shirley observe and how can this observation lead to the necessary conclusion?

2. Use dimensional analysis to convert your weight into Newtons. (1 N = 0.22 pounds)

3. What is the mass and weight of a 10-kg object on earth?

Mass: Weight:

What is the mass and weight of a 10-kg object on the moon where the force of gravity is 1/6th that of the Earth’s?

Mass: Weight:

Conclusion: The of an object is independent of the object’s location in space.

4. The standard metric unit for mass is and the standard metric unit for weight is .

5. Inertia can best be described as_______.

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a. The force which keeps moving objects moving and stationary objects at rest. b. The willingness of an object to eventually lose its motion. c. The force which causes all objects to stopd. The tendency of any object to resist change and keep doing whatever it’s doing.

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Inertia Unit Study Guide

Part 1: Reviewq Look through all of the pages in this unit. Is there anything you did not complete? Finish it

now as extra practice for the test. q Look back over your Cornell notes for this unit. Cover the right half of the page and see if

you can answer the questions on the left. Study any information you cannot answer without peeking at the right side.

q Use your concept cards to study key terms. q Practice rearranging the equations we used this unit. Determine the most important ones

and include them on your “cheat sheet”.q Read the summaries you wrote for each set of notes. Underline important or key terms.

Part 2: Practice1. Which object has more inertia: a bowling ball or a tennis ball? Explain.

2. How does inertia influence your ability to roll a bowling ball versus a tennis ball? Explain.

3. Define Newton’s first law in your own words:

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4. Rank the objects below from smallest to largest inertia:

m = 10 kg m = 5 kg m = 20 kg m = 8 kg m = 3 kg


5. A toy car is rolled across the floor and slowly comes to a stop. Aristotle would say that this was because…

a. It seeks its natural state, which is rest. b. Its inertia causes it to stop moving. c. Friction causes it to slow down.

6. How would Galileo & Newton answer question #5?a. It seeks its natural state, which is rest. b. Its inertia causes it to stop moving. c. Friction causes it to slow down.

7. The best measure of an object’s inertia is it’s…a. Volume b. Mass c. Weight

8. What is the net force needed to keep a rocket moving uniformly in space?a. 9.8 Nb. 0 Nc. The weight of the rocket

9. When a bus moves forward suddenly, a passenger standing in the aisle….a. Feels like she is falling backwardsb. Actually remains at rest while the bus accelerates forwardc. Obeys Netwon’s Law of Inertiad. All of these

10. If a net force acting upon an object is 0 N, then the object MUST:a. Be movingb. Be acceleratingc. Be at restd. Be moving with a constant speed in the same directione. Either C or D

11. Different masses are hung on a spring scale calibrated in Newtons. The force exerted by gravity on 1 kg = ~10 N.

The force exerted by gravity on 5 kg =

The force exterted by gravity on 70 kg =

12. Complete the table below:

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Object Mass Approx. Weight

Melon 1 kg

Apple 1.0 N

Shipping crate 25 kg


13. Find the weights of these objects:

a. 1800 kg car

b. 0.12 kg baseball

14. Find the masses of these objects:

a. 14 N box

b. 680 N girl

15. A 75 kg astronaut travels to the moon. What is his weight…

a. On earth?

b. On the moon, where g = 1.6 m/s2

16. In the diagram below, a ball is released and allowed to roll down the ramp. Draw how far up the other side will the ball reach before rolling back down.

For the statements below, indicate “true” or “false”. If false, explain why the response is false.

17. The law of inertia only applies to moving objects.

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18. An object with twice as much weight has twice as much inertia.

19. Gravity on the moon is stronger than gravity on earth.


20. A 15-N force pushes a box towards the left. A 23-N force pushes the box towards the right. What is the net force on the objet? Is the object at equilibrium? Draw a free body diagram below.

21. A book encounters the following forces simultaneously: 2-N to the right, 1-N to the left, 2.5-N to the right, 1.5-N to the left, and 2-N to the left. What is the net force on the objet? Is the object at equilibrium? Draw a free body diagram below.

22. A light is suspended by a pair of ropes with 120 degrees between them (each 60 degrees from the vertical). The tension in each rope is Draw a free body diagram below.

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23. A 500-N woman stands with one foot on a different scale. How much does each scale read?

24. What happens to an object moving across a completely frictionless surface?a. Over time it slows down to a stopb. Over time it speeds upc. It continues along the same unless acted on by an outside force

25. The image below shows a close-up of two surfaces. Which surface has more friction? Explain

26. On the surface of Jupiter, the acceleration due to gravity is 3 times that of earth. How much

would a 0.50 kg rock weigh on Jupiter? (show your work!)

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Inertia Unit Concept Map(see page 19 for directions)

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Inertia Unit Concept Cards

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Inertia Unit Back Page

The California Dept. of Education Standards I have come to understand are:q 1. Newton’s laws predict the motion of most objects. As a basis for understanding this

concept: q a. Students know how to solve problems that involve constant speed and average

speed. q b. Students know that when forces are balanced, no acceleration occurs; thus an

object continues to move at a constant speed or stays at rest (Newton’s first law).

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Documents

Inertia Unit Student Design Cover Page - Web viewSkim through Chapter 4 of your textbook ... 4.3 . Galileo argued that ... Stack four washers one on top of the other so that you form