Q. A car of mass $1000\ kg$ accelerates uniformly from rest to a velocity of 54 km/hour in $5s$. The average power of the engine during this period in watts is (neglect friction)
A) $2000\ W$
B) $22500\ W$
C) $5000\ W$
D) $2250\ W$
Explanation
(b) Power $= \frac{Work\ done}{time} = \frac{Increase\ in\ K.E.}{time}$
$P = \frac{\frac{1}{2}mv^{2}}{t} = \frac{\frac{1}{2}{\times 10}^{3} \times (15)^{2}}{5} = 22500\ W$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.