$A$ ball of mass $0.1 \,kg$ strikes a wall normally with a speed of $30 \,ms^{-1}$ and rebounds with a speed of $20 \,ms^{-1}$. The impulse of the force exerted by the wall on the ball is (in $\,N-s$)

Two balls each of mass $250 \ g$ moving in opposite directions each with a speed $16 \ m \ s^{-1}$ collide and rebound with the same speeds. The impulse imparted to one ball due to the other is

$A$ ball of mass $0.5 \ kg$ moving horizontally at $10 \ m \ s^{-1}$ strikes a vertical wall and rebounds with speed $v$. The magnitude of the change in linear momentum is found to be $8.0 \ kg \ m \ s^{-1}$. The magnitude of $v$ is, (in $m \ s^{-1}$)

Explain why a seasoned (experienced) cricketer pulls their hands backward while catching a fast-moving cricket ball,whereas a novice (inexperienced) player might hurt their hands by keeping them fixed.

Three different projectiles,each with the same mass $m$,are fired with speed $v$ at a wall. In case $A$,the projectile bounces straight back with speed $v$. In case $B$,the projectile sticks to the wall. In case $C$,the projectile crashes through the wall and emerges with half its original speed. These three cases are shown in the figure. Place the magnitude of the impulse exerted by the wall on the projectile in each of these three cases in the correct order.

$A$ tennis ball is dropped onto the floor from a height of $9.8\,m$. It rebounds to a height of $5.0\,m$. The ball comes in contact with the floor for $0.2\,s$. The average acceleration during contact is $..........\,m/s^2$. [Given $g = 10\,m/s^2$]