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.

Options

A. at the highest position of the body
B. at the instant just before the body hits the earth
C. it remains constant all through
D. at the instant just after the body is projected

Answer

`(2)`

Explanation

Power , `P = vec F vec v = Fv cos theta`
Just before hitting the earth `theta = 0^(@)`. Hence, the power exerted by the gravitational force is greatest at the instant just before the body hits the earth.