A block of mass $m$ is moving with a velocity $u$ on a smooth horizontal surface towards a wedge of same mass initially kept at rest. Wedge is free to move in any direction. Initially the block moves up the smooth incline plane of the wedge to a height $h$ and again moves down back to the horizontal plane. In this process the wedge gains a velocity equal to

A particle of mass $1\, kg$ moving with velocity $1\, m/s$, collides elastically with another particle of mass $m$. In the collision particle of mass $1\, kg$ loses $\frac{3}{4}$of its $K.E.$ The value of $m$ is :

A $1.0\, kg$ ball drops vertically into a floor from a height of $25\, cm$. If rebounds to a height of $4\ cm$. The coefficient of restitution for the collision is

A ball loses $15.0\%$ of its kinetic energy when it bounces back from a concrete wall. With what speed you must throw it vertically down from a height of $12.4\, m$ to have it bounce back to the same height (ignore air resistance)? ............. $\mathrm{m} / \mathrm{s}$

A body of mass $m$  moving with velocity $v$ collides head on with another body of mass $2m $ which is initially at rest. The ratio of K.E. of colliding body before and after collision will be

A ball strikes against the floor and returns with double the velocity; in which type of collision is it possible?