Draw a schematic diagram of nuclear power plant.

A spring of spring constant $\mathrm{K}= 4\mathrm{x}{10}^3\mathrm{N}/\mathrm{m}$ is compressed by $2 \mathrm{cm}$, then determine the potential energy stored in spring. 

Ratio of potential energies of body A and body B will be

A bullet of mass $50 \mathrm{g}$ is moved with a velocity of $500 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right.$. It penetrates $10 \mathrm{cm}$ into a still target and comes to rest. Calculate the kinetic energy possessed by the bullet.