Q. A fan is making 600 revolutions per $minute$. If after some time it makes 1200 revolutions per $minute$, then increase in its angular velocity is
A) $10\ \pi\ rad/sec$
B) $20\ \pi\ rad/sec$
C) $40\ \pi\ rad/sec$
D) $60\ \pi\ rad/sec$
Explanation
(b) Increment in angular velocity $\omega = 2\pi(n_{2} - n_{1})$
$\omega = 2\pi(1200 - 600)\frac{rad}{\min} = \frac{2\pi \times 600\ }{60}\frac{rad}{s} = 20\pi\frac{rad}{s}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.