Question
A body projected vertically from the earth reaches a height equal to earth’s radius before returning to the earth. The power exerted by the gravitational force is greatest
A.
at the instant just before the body hits the earth
B.
it remains constant all through
C.
at the instant just after the body is projected
D.
at the highest position of the body
Answer :
at the instant just before the body hits the earth
Solution :
We know that, Power, $$P = F \cdot V = FV\cos \theta $$
So, just before hitting, $$\theta $$ is zero, power will be maximum.