$A$ particle of mass $m \, kg$ moving with a velocity $v \, m/s$ strikes a surface as shown in the figure and rebounds with the same speed. The magnitude of the change in momentum is:

Two billiard balls of equal mass $30 \, g$ strike a rigid wall with the same speed of $108 \, km/h$ (as shown) but at different angles. If the balls get reflected with the same speed, then the ratio of the magnitude of impulses imparted to ball $'a'$ and ball $'b'$ by the wall along the $'X'$ direction is:

$A$ particle of mass $m$ strikes elastically on a wall with velocity $v$,at an angle of $60^{\circ}$ from the wall. The magnitude of the change in momentum of the particle along the wall is:

$A$ block of mass $2 \ kg$ moves freely along the $x$-axis. It is at rest at $t = 0$. The force $F(t)$ acting on the block varies with time $t$ as shown in the figure. What is the kinetic energy of the block after $4.5 \ s$ (in $J$)?

$N$ number of balls,each of mass $m \ kg$,moving along the positive direction of the $x$-axis,strike a wall per second and return elastically. The velocity of each ball is $u \ m/s$. The force exerted on the wall by the balls in newtons is:

$A$ batsman hits back a ball of mass $0.4 \; kg$ straight in the direction of the bowler without changing its initial speed of $15 \; ms^{-1}$. The impulse imparted to the ball is $\dots \; Ns$.