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

B

Explanation

Power = Force `xx` Velocity
When a body projected vertically from the earth returns to earth, then its velocity is maximum when it is just above earth.s surface. Therefore, power exerted by the gravitational force will be greatest at this position.