Body of mass $M$ is much heavier than the other body of mass $m$. The heavier body with speed $v$ collides with the lighter body which was at rest initially elastically. The speed of lighter body after collision is
$2 v$
$3 v$
$v$
$\frac{v}{7}$
Hail storms are observed to strike the surface of the frozen lake at $30^o$ with the vertical and rebound at $60^o$ with the vertical. Assume contact to be smooth, the coefficient of restitution is
A body of mass $5\,kg$ strikes another body of mass $2.5\,kg$ initially at rest. The bodies after collision coalesce and begin to move as a whole with a kinetic energy of $5\,J$. The kinetic energy of the first body before collision is ............... $\mathrm{J}$
A projectile of mass $3m$ is moving at $40\, m/s$ at is highest point, where it breaks into two parts $m$ and $2m$. Mass $2m$ moves vertically up at $25\, m/s$. The other part will move at speed .................... $\mathrm{m}/ \mathrm{s}$
Find work done by friction if block reaches to the end with constant velocity
A rubber ball is released from a height of $5\, m$ above the floor. It bounces back repeatedly, always rising to $\frac{81}{100}$ of the height through which it falls. Find the average speed of the ball. (Take $g =10 ms ^{-2}$ ) (in $ms ^{-1}$)