Question

How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.

Answer 1

The relation between work, force, distance and angle between the two is:
W = (F) (S) cos θ
Where,
(W) - Work done
 (F)- Force
 (S)- Displacement
 (θ) - Angle between force and displacement
The work done by the earth on a satellite moving in a circular orbit around it is zero, as gravitational force is perpendicular to the direction of motion at every instant, and hence, the work done is zero.