1. Complete the following statement: When a net torque is applied to a rigid object, it always produces a
A.constant acceleration.
B.rotational equilibrium.
C.constant angular velocity.
D.constant angular momentum.
E.change in angular velocity.

2. A wrench is used to tighten a nut as shown in the figure. A 12-N force is applied 7.0 cm from the axis of rotation. What is the torque due to the applied force?

A.0.58 N • m
B.0.84 N • m
C.1.71 N • m
D.14 N • m
E.58 N • m

3. A string is tied to a doorknob 0.79 m from the hinge as shown in the figure. At the instant shown, the force applied to the string is 5.0 N. What is the torque on the door?

A.3.3 N • m
B.2.2 N • m
C.1.1 N • m
D.0.84 N • m
E.0.40 N • m

4. A uniform 13-kg trap door is oriented horizontally and hinged as shown. What is the magnitude of the torque on the door at the instant that the release is activated and the door can freely rotate?

A.4.9 N • m
B.9.8 N • m
C.48 N • m
D.72 N • m
E.96 N • m

5. Complete the following statement: A body is in translational equilibrium
A.only if it is at rest.
B.only if it is moving with constant velocity.
C.only if it is moving with constant acceleration.
D.if it is either at rest or moving with constant velocity.
E.if it is moving with either constant velocity or constant acceleration.

6. A horizontal, 10-m plank weighs 100 N. It rests on two supports that are placed 1.0 m from each end as shown in the figure. How close to one end can an 800-N person stand without causing the plank to tip?

A.0 m
B.0.2 m
C.0.5 m
D.0.6 m
E.0.8 m

7. A 3.0-kg ball and a 1.0-kg ball are placed at opposite ends of a massless beam so that the system is in equilibrium as shown. Note: The drawing is not drawn to scale. What is the ratio of the lengths, b/a?


8. One end of a rope is tied to the handle of a horizontally-oriented and uniform door. A force F is applied to the other end of the rope as shown in the drawing. The door has a weight of 145 N and is hinged on the right. What is the magnitude of F at which the door will remain at rest?

A.145 N
B.265 N
C.381 N
D.424 N
E.530 N

9. A meter stick is pivoted at the 0.50-m line. A 3.0-kg object is hung from the 0.10-m line. Where should a 5.0-kg object be hung to achieve equilibrium?
A.0.06-m line
B.0.24-m line
C.0.56-m line
D.0.74-m line
E.A 5.0-kg object cannot be used to sustain equilibrium in this system.

10. In this drawing, the large wheel has a radius of 8.5 m. A rope is wrapped around the edge of the wheel and a 7.6 kg-box hangs from the rope. A smaller disk of radius 1.9 m is attached to the wheel. A rope is wrapped around the edge of the disk as shown. An axis of rotation passes through the center of the wheel-disk system. What is the value of the mass M that will prevent the wheel from rotating?

A.1.7 kg
B.3.8 kg
C.12 kg
D.34 kg
E.46 kg

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