AP Physics AP Physics Rotational Motion & Gravitation

Question 1

A solid disk of mass M and radius R rotates about its center. What is its moment of inertia?

Accepted Answer

(1/2)MR²

Answer

MR²

Answer

(2/3)MR²

Answer

(2/5)MR²

Question 2

A net torque of 12 N·m acts on an object with a moment of inertia of 4 kg·m². What is the angular acceleration?

Accepted Answer

3 rad/s²

Answer

48 rad/s²

Answer

0.33 rad/s²

Answer

8 rad/s²

Question 3

Which quantity is conserved when no net external torque acts on a system?

Accepted Answer

Angular momentum

Answer

Kinetic energy

Answer

Linear momentum

Answer

Torque

Question 4

A planet orbits the Sun in an elliptical path. According to Kepler's second law, what remains constant?

Accepted Answer

Area swept per unit time

Answer

Orbital speed

Answer

Distance from the Sun

Answer

Gravitational force

Question 5

The gravitational force between two masses is F. If the distance between them is doubled, the new force is:

Accepted Answer

F/4

Answer

4F

Answer

2F

Answer

F/2

Question 6

A wheel starts from rest and reaches 60 rad/s in 10 s with constant angular acceleration. What is α?

Accepted Answer

6 rad/s²

Answer

600 rad/s²

Answer

0.17 rad/s²

Answer

70 rad/s²