A satellite is revolving round the earth in an elliptical orbit, then
(a) gravitational force exerted by the earth is equal to centripetal force at same point only
( b) power associated with gravitational force is zero at every point
(c) workdone by gravitational force is zero in some small parts of the orbit
(d) at some points, the magnitude of gravitational force is greater than that of centripetal force

Options

A. only a and b are true
B. only b&c are true
C. only a,b & d are true
D. only a,c,d are true

Answer

D