Consider elastic collision of a particle of mass $m $ moving with a velocity $u$ with another particle of the same mass at rest. After the collision the projectile and the struck particle move in directions making angles ${\theta _1}$and ${\theta _2}$respectively with the initial direction of motion. The sum of the angles. ${\theta _1} + {\theta _2},$ is......$^o$

Two billiard balls undergo a head-on collision. Ball $1$ is twice as heavy as ball $2$. Initially, ball $1$ moves with a speed $v$ towards ball $2$ which is at rest. Immediately after the collision, ball $1$ travels at $a$ speed of $v/3$ in the same direction. What type of collision has occured?

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 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 steel ball is released from rest a distance above a rigid horizontal surface and bounces several time. The diagram shows how its velocity varies with time. Which statement correctly explains why the areas $X$ and $Y$ are equal?

A ball of mass $m$ suspended from a rigid support by an inextensible massless string is released from a height $h$ above its lowest point. At its lowest point, it collides elastically with a block of mass $2 m$ at rest on a frictionless surface. Neglect the dimensions of the ball and the block. After the collision, the ball rises to a maximum height of