$N$ bullets each of mass $m \,kg$ are fired with a velocity $v\,m{s^{ - 1}}$ at the rate of n bullets per second upon a wall. The reaction offered by the wall to the bullets is given by

Below figure shows the position-time graph of a body of mass $0.04\; kg$. Suggest a suitable physical context for this motion. What is the time between two consecutive impulses received by the body ? What is the magnitude of each impulse ?

“Momentum and changes in momentum are not always in same direction”. Explain by suitable example.

$100$ balls each of mass moving with speed $v$ simultaneously strike a wall normally and reflected back with same speed, in time $t s$. The total force exerted by the balls on the wall is

A $40\ g$ ball dropped from a certain height bounces back from the horizontal ground without losing mechanical energy. If its speed is $10\ m/s$ just before making contact with the ground, and the average value of the force of the ground on the ball is equal to $16\ N$ while ball and wall are in contact, how long were they in contact .......... $m/s$ 

Action and reaction forces act on