Q: Power delivered to a body varies as P = 3 t2 . 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