The capability to do work is called .

State an example of renewable resource.

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. 

A force is applied upon a body of 40 kg then its velocity increases from 1
metre/second to 2 metre/second. Determine work done by the force.

An object of mass $10 \mathrm{kg}$ is dropped from a height of $20 \mathrm{m}$. Calculate the potential energy and kinetic energy of the object at various heights as mentioned in the data:

Show by calculations that the above data verifies the law of conservation of energy. (take $\mathrm{g}=10 \mathrm{m}/{\mathrm{s}}^2$ )