$A$ bomb is kept stationary at a point. It suddenly explodes into two fragments of masses $1\,g$ and $3\,g$. The total kinetic energy ($K$.$E$.) of the fragments is $6.4 \times 10^4\,J$. What is the $K$.$E$. of the smaller fragment?

$A$ ball is held in the position shown with a string of length $L = 1 \, m$ just taut and then projected horizontally with a velocity of $u = 3 \, m/s$. If the string becomes taut again when it is vertical,the angle $\theta$ is given by ........ $^o$.

$A$ block of mass $1 \ kg$ is moved by a distance of $1 \ m$ on a horizontal surface by applying a force of $8 \ N$. Then it is lifted to a height of $2 \ m$. The total work done is ... $J$. (Take $g = 10 \ m/s^2$)

$A$ toy of mass $20 \,g$ at rest acquires a velocity $(3 \hat{i}-2 \hat{j}) \,m/s$ in $2 \,s$. The power of the toy is: (in $\,W$)

$A$ ball of mass $1\,kg$ moving with a velocity of $4\,m/s$ collides with a stationary ball of mass $M$. The collision is oblique. After the collision,the first ball moves at a right angle to its initial direction with a velocity of $3\,m/s$. The momentum of the second ball (in $kg\cdot m/s$) after the collision would be nearly:

Work done by the frictional force is