AP Physics 1 Question 13: Answer and Explanation

Test Information

Use your browser's back button to return to your test results.

Question: 13

3. If the force of gravity between the Moon and the Earth were to stop, which statement best describes the resulting motion of the moon?

  • A. It would continue rotating on its axis, and it would revolve around the Earth as usual.
  • B. It would continue rotating on its axis, but it would stop revolving around the Earth.
  • C. It would stop rotating on its axis, but it would revolve around the Earth as usual.
  • D. It would stop rotating on its axis, and it would stop revolving around the Earth.

Correct Answer: B

Explanation:

B First, it would stop revolving around the Earth because gravity is providing the centripetal force. Without that, you cannot have uniform circular motion. The Moon would simply fly off in whichever direction it was moving at the moment gravity ceased.

Second, the Moon would continue rotating because gravity affects an object's center of mass. Therefore, it cannot provide torque, so it cannot have any effect on rotation.