Q. A symmetrical body is rotating about its axis of symmetry, its moment of inertia about the axis of rotation being 4 kg-$m^{2}$ and its rate of rotation 2 rev/s. The angular momentum is
A) 1.257 kg $m^{2}s^{- 1}$
B) 12.57 kg $m^{2}s^{- 1}$
C) 13.57 kg $m^{2}s^{- 1}$
D) 20 kg $m^{2}s^{- 1}$
Explanation
(b) Given, $I = 1\ kg - m^{2},\ n = 2\ rps$
$\omega = 2\pi n = 2\pi \times 2 = 4\pi\ rads^{- 1}$
$L = I\omega = 1(4\pi) = 12.57\ kg - m^{2}s^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.