An average force of $125\,N$ is applied on a machine gun firing bullets each of mass $10\,g$ at the speed of $250\,m/s$ to keep it in position. The number of bullets fired per second by the machine gun is:

$A$ particle of mass $m$, initially at rest, is acted upon by a variable force $F$ for a brief interval of time $T$. It begins to move with a velocity $u$ after the force stops acting. The graph shows $F$ as a function of time, where the curve is a semicircle with peak force $F_0$ at time $T/2$.

The position-time graph of a body of mass $2\, kg$ is as given in the figure. What is the impulse on the body at $t = 0\, s$ and $t = 4\, s$ (in $, Ns$)?

Two trains $A$ and $B$ are running in the same direction on parallel rails such that $A$ is faster than $B$. Packets of equal weight are transferred between them. What will happen due to this?

$A$ ball of mass $0.5\, kg$ moving with a velocity of $2\, m/s$ strikes a wall normally and bounces back with the same speed. If the time of contact between the ball and the wall is $1\, ms$,the average force exerted by the wall on the ball is ......... $N$.

$A$ player caught 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 magnitude of the force exerted by the ball on the hand of the player is .......... $N$.