Q. A fly wheel rotates about a fixed axis and slows down from 300 rpm to 100 rpm in 2 min. Then its angular retardation in $rad$/$\min^{2}\ $is
A) $\frac{100}{\pi}$
B) 100
C) 100 $\pi$
D) 200 $\pi$
Explanation
(d) $\omega_{1} = 2\pi \times 300$ rad/min
$\omega_{2} = 2\pi \times 100$ rad/min
Angular retardation
$\alpha = \frac{\omega_{1} - \omega_{2}}{2}$
$= \frac{2\pi \times 300 - 2\pi \times 100}{2}$
$= 2\pi \times 100$ rad/$\min^{2}\ $
$= 200\pi$ rad/$\min^{2}\ $
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.