Q. A particle of mass 2 kg starts moving in a straight line with an initial velocity of $2\ ms^{- 1}$ at a constant acceleration of $2\ ms^{- 2}$. Then rate of change of kinetic energy
A) Is four times the velocity at any moment
B) Is two times the displacement at any moment
C) Is four times the rate of change of velocity at any moment
D) Is constant through out
Explanation
(a) $K = \frac{1}{2}mv^{2}$
$\frac{dK}{dt} = mv.\frac{dv}{dt}$
$= \left( m\frac{dv}{dt} \right)v = (ma\ v = 4v)$
As $m = 2$ kg and $a = 2\ ms^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.