Question

what is the work done by the force of gravity on a satellite moving roung the earth ? justify your answer

Answer 1

the work done by the force of gravity on satellite around earth is always zero.
Because we know that the formula for work done is W=F s cos they a
thus as the satellite is always perpendicular to the centre of earth and cos90 is zero ,thus the work done is zero....

Answer 2

Work is done whenever the given two conditions are satisfied: (i) A force acts on the body. (ii) There is a displacement of the body by the application of force in or opposite to the direction of the force. If the direction of the force is perpendicular to displacement, then the work done is zero. If the satellite is in a perfectly circular orbit, then the force of gravity is always perpendicular to the satellite's velocity, and gravity never does any work. If the orbit isn't circular, then there is a radial component of velocity at most points in the orbit, and some gravitational acceleration, work, etc., but those are exactly matched by negative values at other points in the orbit, and the total over a complete orbit is zero again.