A body falls freely under gravity. Its speed is v when it has lost an amount U of gravitational ener

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7.Gravitation

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A body falls freely under gravity. Its speed is $v$ when it has lost an amount $U$ of the gravitational energy. Then its mass is

A

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

B

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

C

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

D

$2\,Ug{v^2}$

Solution

(c) $U =$ Loss in gravitational energy = gain in $K.E.$

So, $U = \frac{1}{2}m{v^2}\, \Rightarrow \,m = \frac{{2U}}{{{v^2}}}$

Standard 11

Physics

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