$A$ body of mass $M$ collides against a wall with a velocity $v$ and retraces its path with the same speed. The change in momentum is (take initial direction of velocity as positive).

$A$ $40 \ g$ 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 $16 \ N$ while the ball and ground are in contact,how long were they in contact in milliseconds $(ms)$?

$A$ ball of mass $3 \ kg$,moving with a speed of $100 \ m/s$,strikes a wall at an angle of $60^{\circ}$ with the wall (as shown in the figure). The ball rebounds at the same speed and remains in contact with the wall for $0.2 \ s$. The force exerted by the ball on the wall is:

$A$ 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?

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 $, Ns$)?

$A$ body of $2\, kg$ has an initial speed of $5\, ms^{-1}$. $A$ force acts on it for some time in the direction of motion. The force-time graph is shown in the figure. Find the final speed of the body in $ms^{-1}$.