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Work Energy and Power question

2011 · Q153
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Work Energy and Power question

2011 · Q153

NEETPhysicsWork Energy and PowerMCQ+4 / −1
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
  1. A
    at the highest position of the body
  2. B
    at the instant just before the body hits the earth.
  3. C
    it remains constant all through.
  4. D
    at the instant just after the body is projected.
View written solutionFree

Correct answer: B

Power, P = F→.v→=Fvcos⁡θ\overrightarrow F .\overrightarrow v = Fv\cos \theta F.v=Fvcosθ
Just before hitting the earth θ\theta θ = 0°. Hence, the power exerted by the gravitational force is greatest at the instant just before the body hits the earth.

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