Work, Power and EnergyHard
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
Options
A.at the heighest 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
Solution
Power, P = 
= Fv cos θ
Just before hitting the earth θ = 0o. Hence, the power exerted by the gravitational force is greatest at the instant just before the body hits the earth.
= Fv cos θJust before hitting the earth θ = 0o. Hence, the power exerted by the gravitational force is greatest at the instant just before the body hits the earth.
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