Q. The energy required to accelerate a car from rest to $10\ ms^{- 1}$ is $E$. What energy will be required to accelerate the car from $10\ ms^{- 1}$ to $20\ ms^{- 1}$?
A) $E$
B) $3E$
C) $5E$
D) $7E$
Explanation
(b) $E = \frac{1}{2}m\left( 20^{2} - 10^{2} \right) = \frac{1}{2}m \times 30 \times 10$
$E = \frac{1}{2}m \times 10 \times 10$
$\therefore\ \ \frac{E'}{E} = \frac{\frac{1}{2}m \times 30 \times 10}{\frac{1}{2}m \times 10 \times 10} = 3\ \ or\ \ E^{'} = 3E$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.