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
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at the instant just before the body hits the earth
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it remains constant all through
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at the instant just after the body is projected
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at the highest position of the body
Solution
A.
at the instant just before the body hits the earth
We know
P = F. v = Fv cos θ
so just before hitting θ is zero and both F and v are maximum
