Chapter 8: Rotational Motion

The unit of angular velocity is

• m/s

• m/s²

• rad/s

• rad/s²

A wrench is used to tighten a nut. A 15N perpendicular force is applied 50cm away from the axis of rotation, and moves a distance of 10 cm as it turns. What is the torque applied to the wrench?

• 7.5 Nm
• 1.5 Nm
• 750 Nm
• 150 Nm

The easiest way to open a heavy door  is by applying the force

• Near the hinges
• In the middle of the door
• At the edge of the door far from the hinges
• At the top of the door

What is the Unit for Torque

• Nm
• N
• W
• J

If the torque required to loosen a nut on the wheel of a car has a magnitude of 60.0 N• m, what minimum perpendicular force must be exerted by a mechanic at the end of a 45.0 cm wrench to loosen the nut?

• .666 Nm
•  133.3 N
• 66.7 N
• 13.3 Nm

The property of a body to resist change in motion.

• mass
• weight
• volume
• inertia

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,

• her moment of inertia increases and her angular speed decreases.
• her moment of inertia decreases and her angular speed increases.
• her moment of inertia increases and her angular speed increases.
• her moment of inertia increases and her angular speed remains the same.

What is the weight of the package?

• 5 N
• 10 N
• 15 N
• 20 N

A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three of them are released simultaneously at the top of an inclined plane and do not slip, which one will reach the bottom first?

• cylinder
• pipe
• sphere
• They all reach the bottom at the same time.

Does a bridge anchored resting on two pillars have any torque?

• No, it isn't moving
• Yes, but it is at equilibrium
• Yes, but it will soon break because of the torque
• No, Bridges can't have torque