Q: Power delivered to a body varies as P = 3 t^{2} . Find out the change in kinetic energy of the body from t = 2 to t = 4 sec.

Ans: 56 J

Solution: Applying work energy theorem to body ΔKE = work done by forces delivering power

$= \int_{t=2}^{t=4} P dt $

$= \int_{t=2}^{t=4} 3 t^2 dt $

= 56 J