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Physics - W.E.P. Question with Solution | TestHub

PhysicsW.E.P.MiscellaneousMedium2 minQB

PhysicsMediumnumerical

A body is dropped on ground from a height $h_{1}$ and after hitting the ground, it rebounds to a height $h_{2}$ . If the ratio of velocities of the body just before and after hitting ground is $4$ , then percentage loss in kinetic energy of the body is $\frac{x}{4}$ . The value of $x$ is _____.

Answer:

375.00

Solution:

The given ratio of the velocities is
$\frac{v_{1}}{v_{2}} = 4$
The percentage loss in kinetic energy is
$\frac{\frac{m {v^{2}}_{1}}{2} - \frac{m {v^{2}}_{2}}{2}}{\frac{m {v^{2}}_{1}}{2}} \times 100 = \frac{x}{4} \Rightarrow \frac{{v^{2}}_{1} - {v^{2}}_{2}}{{v^{2}}_{1}} = \frac{x}{400} \Rightarrow 1 - \frac{{v^{2}}_{2}}{{v^{2}}_{1}} = \frac{x}{400} \Rightarrow 1 - \frac{1}{16} = \frac{x}{400} \Rightarrow x = 375$

Stream:JEESubject:PhysicsTopic:W.E.P.Subtopic:Miscellaneous

⏱ 2mℹ️ Source: QB

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