A body is falling under gravity from rest. When it loses a gravitational potential energy by U, its

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5.Work, Energy, Power and Collision

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A body is falling under gravity from rest. When it loses a gravitational potential energy by $U,$ its speed increases to $v.$ The mass of the body shall be

A

$\frac {2U}{v}$

B

$\frac {U}{2v}$

C

$\frac {2U}{v^2}$

D

$\frac {U}{2v^2}$

Solution

Gain in $K E=loss$ in $P E$ or $\frac{1}{2} m v^{2}=U$

or $m=\frac{2 U}{v^{2}}$

Standard 11

Physics

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