A ball falls vertically onto a floor with momentum $p$ and then bounces repeatedly. If the coefficient of restitution is $e$  then the total momentum imparted by the ball on the floor is

A ball of mass $1\,\,kg.$  moving with a velocity of $4\,\,m/sec.$  collides with a stationary ball. The collision is oblique. After the collision the first moves at right angle to its, initial direction with a velocity of  $3\,\,m/s.$  The momentum of the second ball (in $kg.\,\,m/s.$ ) after collision would be nearly

An inelastic ball is dropped from a height of $100\, m$. Due to earth$20\%$ of its energy is lost. To what height the ball will rise ......... $m$

Four smooth steel balls of equal mass at rest are free to move along a straight line without friction. The first ball is given a velocity of $0.4 \,m/s$. It collides head on with the second elastically, the second one similarly with the third and so on. The velocity of the last ball is .......... $m/s$

A particle $P$ moving with speed $v$  undergoes a head -on elastic collision with another particle $Q$ of identical mass but at rest. After the collision

Two balls $A$ and $B$ having masses $1\, kg$ and $2\, kg$, moving with speeds $21\, m/s$ and $4\, m/s$ respectively in opposite direction, collide head on. After collision Amoves with a speed of $1\, m/s$ in the same direction, then the coefficient of restitution is