In a force $F$ versus time $t$ graph for an object,the area enclosed in a time interval of $1 \ s$ is $100 \ Ns$. Calculate the magnitude of the force. (in $N$)

$A$ ball of mass $3 \ kg$ strikes a wall at an angle of $60^\circ$ with a velocity of $10 \ m/s$ and rebounds at the same angle and speed. What is the change in momentum of the ball in $MKS$ units?

$A$ particle moves in the $xy$-plane under the action of a force $\vec{F}$ such that the components of its linear momentum $\vec{p}$ at any time $t$ are $p_x = 2\cos t$ and $p_y = 2\sin t$. The angle between $\vec{F}$ and $\vec{p}$ at time $t$ is ........... $^o$.

$A$ 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 $g = 10\,m/s^2$]

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

$A$ ball of mass $0.2 \ kg$ moving with a speed of $20 \ m s^{-1}$ is brought to rest in $0.1 \ s$. The average force applied to the ball is (in $N$)