Rotational inertia

The figure shows scale drawings of four objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the greatest moment of inertia when rotated about an axis perpendicular to the plane of the drawing at point P?

• A
• B
• C
• D

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.

Two uniform solid balls, one of radius R and mass M, the other of radius 2R and mass 8M, roll down a high incline. They start together from rest at the top of the incline. Which one will reach the bottom of the incline first?

• The small sphere arrives first.
• The large sphere arrives first.
• Both reach the bottom at the same time.

Which has greater angular speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

• The inside horse
• The outside horse
• Neither - they both have the same angular speed

Torque is the product of a force exerted on an object times the lever arm.

• True 
• False

The moment of inertia:

• is synonymous with mass
• does not depend on where the mass is located
• resistance to a change in rotational inertia
• more resistance to change = less inertia

When an object is experiencing a net torque

• it is in dynamic equilibrium.
• it is in static equilibrium.
• it is rotating.
• it is translating.

Calculate the torque produced by 75- N perpendicular force at the end of a 0.20 m long wrench.

• 15 Nm

• 1.5 Nm

• 15.0 Nm

• 16 Nm

What is the distance the masses on the right of the fulcrum need to be to balance with the two masses on the left?

• .65 m
• .56 m
• .79 m
• .39 m