Question

A satellite in low earth orbit experiences a small drag force from the earth's atmosphere. The consequence of this drag force will be

• A. Potential energy decreases, while kinetic energy increases
• B. Potential energy and kinetic energy decreases, since total energy decreases
• C. drag force doesn't have any effect on orbital motion of a satellite
• D. None of the above

Answer 1

Answer: (A), (B)

The correct options are
A Potential energy decreases, while kinetic energy increases
B Potential energy and kinetic energy decreases, since total energy decreases

Due to air drag, the satellite will get heated as some mechanical energy of the satellite will be converted into heat. This in turn implies that the radius of the orbit will decrease and so the satellite will follow a spiral path falling towards the earth.

Due to the air drag, the total energy will decrease, since some energy is lost as heat. The rate at which potential energy decreases will be larger than the rate at which the total energy decreases.

Thus, options (a and b) are correct.