Embibe Experts Solutions for Chapter: Work, Energy and Power, Exercise 1: CG PET 2019

A policeman fires a bullet of mass $50 \mathrm{g}$ with a speed of $200 \mathrm{m} {\mathrm{s}}^{-1}$, in a wooden piece of thickness $2.0 \mathrm{cm}$. The bullet leaves the wooden piece with only $10\%$ of its initial kinctic energy. By how much percentage has the speed of the bullet been reduced?

A ball of mass $m$ is thrown upward with a velocity $v$. If air exerts an average resisting force $F,$ the velocity with which the ball returns to the thrower is

When work done by force of gravity is negative, then

Power applied to a particle varies with time as $\left(P=3t^2-2t+1\right)W,$ where $t$ is in second. The change in its kinetic energy between $t=2\mathrm{s}$ and $t=4\mathrm{s}$ is

Which of the following graphs represent kinetic energy $\left(K\right),$ potential energy $\left(U\right)$ and height $\left(h\right)$ from the ground for a freely falling body?

Two springs of force constants $k_1$ and $k_2$ are stretched by the same force. The ratio of potential energies stored in them is

In the figure, mass of $A$ is $m$ and that of $B$ is $2\mathrm{m}$. All the surface are smooth. System is released from rest with spring unstretched. Then, the maximum extension $X_m$ in spring will be