Q. A $2\ kg$ mass is rotating on a circular path of radius $0.8\ m$ with angular velocity of $44\ rad/sec$. If radius of path becomes $1\ m$. Then the value of angular velocity will be
A) $28.16\ rad/sec$
B) $35.16\ rad/sec$
C) $19.28\ rad/sec$
D) $8.12\ rad/sec$
Explanation
(a) Angular momentum, $L = mr^{2}\omega =$ constant
$\frac{\omega_{2}}{\omega_{1}} = \left( \frac{r_{1}}{r_{2}} \right)^{2} = \left( \frac{0.8}{1} \right)^{2} = 0.64 \Rightarrow \omega_{2} = 44 \times 0.64 = 28.16\frac{rad}{s}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.