If momentum of a body is increased by 20 % , then its kinetic energy increases by ....%

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5.Work, Energy, Power and Collision

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If momentum of a body is increased by $20 \%$, then its kinetic energy increases by$....\%$

A

$36$

B

$40$

C

$44$

D

$48$

(JEE MAIN-2022)

Solution

$P ^{\prime}= P +\frac{20}{100} P =1.2 P$

$\%$ change in $KE =\frac{ K ^{\prime}- K }{ K } \times 100$

$=\left(\frac{\frac{ P ^{2}}{2 m }-\frac{ P ^{2}}{2 m }}{\frac{ P ^{2}}{2 m }}\right) \times 100$

$= {\left[(1.2)^{2}-1\right] \times 100 }$

$= 44\%$

Standard 11

Physics

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