A car of mass $1500 \mathrm{kg}$ travelling at the speed of $30 \mathrm{m}/\mathrm{s}$ stops after covering a distance of $50 \mathrm{m}$ when brakes are applied.
Calculate
(a) the force exerted on it by the brakes,
(b) work done by the brakes.

A body is allowed to fall under the influence of gravity from a height $h$. When does its

(i) potential energy become maximum;

(ii) potential energy equal kinetic energy;

(iii) kinetic energy become maximum?

Differentiate between work, power and energy.