Q. The angular velocity of a wheel increases from 100 rps to 300rps in 10 s. The number of revolutions made during that time is
A) 600
B) 1500
C) 1000
D) 2000
Explanation
(d) Angular displacement during time
$\theta = \left( \omega_{2} - \omega_{1} \right)t$
$= \left( 2\pi n_{2} - 2\pi n_{1} \right)t$
$= (600\pi - 200\pi) \times 10$
$= 4000\ \pi$ rad
Therefore, number of revolutions made during this time
$= \frac{4000\pi}{2\pi} = 2000$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.