Name __________________________________

E MCH 11 : Statics

EXAM 1

October 16, 2007

INSTRUCTIONS: 1. Read the problems carefully !!! 2. Your exam should contain 3 problems on separate pages and one page of multiple choice

concept questions. If something is missing, notify a proctor immediately. 3. A Free Body Diagram must be shown and used to support your work in each equilibrium

problem. Each sketch must be clear and accurate. 4. Show ALL work in a neat and logical order. Partial credit will only be given if the work and

reasoning are shown clearly and legibly. Begin each problem by clearly indicating what you are trying to FIND.

5. Neatness counts. Points will be deducted for sloppy work. 6. Place answers in the answer blocks provided. Be sure to label your answer and include units.

(write F = 45 lb, not just the number 45 as the answer) 7. Individual calculators only. Sharing of calculators is prohibited. For questions on the grading, write a detailed explanation of your question below, including a description of how the work you originally submitted supports your question. Return this to your instructor no later than Friday, November 2, 2007 and we will review your exam.

Score (out of 100%)

Check off your section number 10:10 – 11:00 am

1 – Daniel / Dr. Masters 2 – Steve / Dr. Masters 3 – Myo / Dr. Masters 4 – Joe / Dr. Masters

11:15 am – 12:05 pm

5 – Myo / Dr. Masters 6 – Shawn / Dr. Masters 7 – Mike / Dr. Masters 8 – Steve / Dr. Masters 13 – Joe / Dr. Masters 14 – Dave / Dr. Masters

2:30 – 3:20 pm

9 – Shawn / Dr. Masters 11 – Dave / Dr. Masters 12 – Tommy / Dr. Masters

Score (out of 225 points)

Problem 1 ( 45 % ) The triangular gate ABC, used to regulate water levels in a reservoir, is pin connected at A and rests against a smooth slanted surface at C. The force of water pushing on the gate can be represented by the distributed load shown below. Neglecting the weight of the gate, determine the magnitude of the force exerted by the pin on the gate at A.

70 0

30 0

1 ft

4 ft

15 ft

300 lb/ft

1000 lb/ft

Problem 2 ( 20 % ) a) Replace the given forces and couple acting on the frame by an equivalent resultant force and couple moment acting at point B. Report the magnitude and direction of both the force and the couple in the box and sketch these on the blank figure.

b) Now replace the loads by an equivalent resultant force and specify where the resultant’s line of action intersects member BC as measured from point B. Sketch this resultant and label it’s location on the figure below.

900 ft-lb

250 lb

100 lb

3 ft A

B

C2 ft

4 ft

5 ft

B

BA

C

Problem 3 ( 25 % ) A worker tries to move a rock by applying a 360 N force perpendicular to a steel bar as shown. If two workers attempt to move the same rock by applying a vertical 100 N force at A and a second force at B, determine the magnitude F, the direction θ, and the location d of this second force so that the two systems will be equivalent.

30 0

0.4 m

360 N

System 1

30 0d

100 N

θ

F

System 2

A

A

B

Problem 4 ( 10 % ) 4.1 (3%) The forces on this pole can be reduced to

a singe resultant force and couple at ______.

A) point A only B) point B only C) point C only D) any point

4.2 (3%) Assuming the pulley is frictionless and

the system is in static equilibrium as shown, what is the tension in the rope?

A) Can’t be determined

B) 2W

C) W

D) W/2

4.3 (4%) The rod shown below is supported by a collar at A and a smooth surface at B. Sketch

the support reaction(s) exerted on the collar at A.