ConceptConceptDocsDocuments

AP Physics 1 2.6: Gravitational Force

Describe gravitational interactions between masses and connect their strength to mass, separation, attractive direction, and circular orbital motion.

Syllabus
Effective Fall 2025
Course
AP Physics 1: Algebra-Based

Exam points

  • Use universal gravitation to compare how mass and distance affect the attractive force between objects.
  • Connect gravitational force with centripetal acceleration in circular-orbit situations.

2.6 Gravitational Force question 1

[Maximum number: 2]

(7 points, suggested time 13 minutes)
A simple pendulum consists of a small sphere that hangs from a string with negligible mass. The top end of the string is fixed. The sphere is pulled to Point A so that the string makes a small angle θ\theta with the vertical, as shown. The sphere is then released from rest and swings through its lowest point at Point B. The work done on the sphere by Earth between points A and B is WEW_{\mathrm{E}}.
The pendulum is then taken to Planet X. The mass of Planet X is the same as the mass of Earth, but the radius of Planet X is greater than the radius of Earth. The sphere is again brought to Point A (displaced θ\theta from the vertical), released from rest, and swings through its lowest point at Point B. The work done on the sphere by Planet X between points A and B is WXW_{\mathrm{X}}.

Justify why WXW_{\mathrm{X}} is less than WEW_{\mathrm{E}}.

A new pendulum is made by hanging the same small sphere from a different string with negligible mass. The new string is slightly elastic, and the length of the string may increase or decrease depending on the tension applied to the string. On Earth, when the sphere is again displaced θ\theta from the vertical and released from rest, the new pendulum oscillates with period TET_{\mathrm{E}}.

The new pendulum is then taken to a different planet, Planet Y. The radius of Planet Y is the same as the radius of Earth, but the mass of Planet Y is larger than the mass of Earth. On Planet Y, when the sphere is again displaced from the vertical and released from rest, the new pendulum oscillates with period TYT_{\mathrm{Y}}.

2.6 Gravitational Force question 2

[Maximum number: 1]

While standing on an elevator and experiencing a downward acceleration of 4.9 m/s24.9 \mathrm{~m} / \mathrm{s}^{2}, what is the force between the floor and your feet? The variable m is your mass.

A

m g

B

0.5 m g

C

1.5 m g

D

4.9 m g

2.6 Gravitational Force question 3

[Maximum number: 1]

If you went to another planet, which of the following would be true?

A

Your mass would be the same, but your weight would change.

B

Your mass would change, but your weight would be the same.

C

Your mass would be the same, and your weight would be the same.

D

Your mass would change, and your weight would change.

All question bank results loaded