A bomb of $12 \,kg$ explodes into two pieces of masses $4 \,kg $ and $8 \,kg$. The velocity of $8\,kg$  mass is $6 m/sec$. The kinetic energy of the other mass is ............. $\mathrm{J}$

A body of mass $10\,kg$ at rest is acted upon simultaneously by two forces $4 \,N$ and $3\,N$ at right angles to each other. The kinetic energy of the body at the end of $10 \,sec$ is .............. $\mathrm{J}$

Two bodies with kinetic energies in the ratio of $4 : 1$ are moving with equal linear momentum. The ratio of their masses is

A lift of mass $M =500\,kg$ is descending with speed of $2\,ms ^{-1}$. Its supporting cable begins to slip thus allowing it to fall with a constant acceleration of $2\,ms ^{-2}$. The kinetic energy of the lift at the end of fall through to a distance of $6 m$ will be $...........kJ.$

A bullet of mass $50 \mathrm{~g}$ is fired with a speed $100 \mathrm{~m} / \mathrm{s}$ on a plywood and emerges with $40 \mathrm{~m} / \mathrm{s}$. The percentage loss of kinetic energy is :

Write the definition of work and kinetic energy.