A satellite completes one full orbit around Earth. The work performed by Earth's gravitational force on the satellite is
A) always positive.
B) zero J.
C) always negative.
D) positive most of the time.
E) negative most of the time.

Question

Quizplus · Accepted Answer

The work performed by the gravitational force is given by the formula W = Fd cosθ, where F is the force, d is the distance, and θ is the angle between the force and the displacement. In the case of a satellite completing one full orbit around Earth, the force and displacement are always perpendicular to each other, so θ = 90°. Therefore, cosθ = 0, and the work done by the gravitational force is zero joules.

A Satellite Completes One Full Orbit Around Earth