Question

What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.

Answer 1

The satellite is moving on around the earth, displacement of the object is perpendicular to the direction of force. $θ = 90°$.
$W = F×s \ cos\ θ$
$W= F×s\ cos\ 90°$
$W= F×0$
$W= 0$
Therefore, work done is zero.