Q. A ball of mass 2 kg and another of mass 4 kg are dropped together from a 60 ft tall building .After a fall of 30 ft each towards earth ,their respective kinetic energies will be in the ratio of
A) $\sqrt{2}:1$
B) 1:4
C) 1:2
D) 1:$\sqrt{2}$
Explanation
(c) Kinetic energy$\ = \frac{1}{2}mv^{2}$
As both balls are falling through same height, therefore they possess same velocity.
$\therefore\ \ \ \ \frac{(KE)_{1}}{(KE)_{2}} = \frac{m_{1}}{m_{2}} = \frac{2}{4} = \frac{1}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.