$A$ player catches a cricket ball of mass $150 \, g$ moving at a speed of $20 \, m/s$. If the catching process is completed in $0.1 \, s$,the force of the blow exerted by the ball on the hands of the player is ........... $N$.

$A$ machine gun fires $20$ bullets per second into a target. Each bullet weighs $150 \, g$ and has a speed of $800 \, m/s$. Find the force necessary to hold the gun in position.

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.

$1000$ small balls,each weighing $1 \text{ g}$,strike $1 \text{ cm}^2$ of area per second with a velocity of $50 \text{ m/s}$ in a normal direction and rebound with the same velocity. The value of pressure on the surface will be:

$A$ bob of mass $10m$ is suspended through an inextensible string of length $l$. When the bob is at rest at the equilibrium position, two particles of mass $m$ each, moving with velocity $u$, strike the bob at an angle of $60^{\circ}$ with the string and get simultaneously attached to it. What is the value of the impulsive tension $J$ in the string during the impact?

$A$ body of mass $m$ collides against a wall with a velocity $v$ and rebounds with the same speed. Its change of momentum is