Question

A satellite of mass 200 kg is displaced by a distance of 2RE from
a point on the Earth’s surface, where RE is the radius of the Earth. Calculate the work done on the satellite by the force of gravitation.

Answer 1

Explanations & Calculations

• Let's assume that this satellite is displaced into the desired orbit at that height so it is meant to follow a circular path around the earth.
• During that journey, the gravitation acts on it perpendicular to its trajectory as the gravitation always directs toward the center of the earth.
• So the force generated due to the gravitation: mg acts in the same way.
• Since the force & the line of motion is always perpendicular to each other, it performs no work.

• So the work done by the gravitation is 0.
• It only prvides the force needed to move in a cicular path.