Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
हिन्दीA solid cylinder of mass \( 20 \text{ kg} \) and radius \( 0.25 \text{ m} \) rotates about its axis of symmetry with angular speed \( 100 \text{ rad s}^{-1} \). The magnitude of the angular momentum of the cylinder about its axis and the kinetic energy associated with rotation are respectively:
Correct answer · Option 4
\( 62.5 \text{ J s} \) and \( 3125 \text{ J} \)
Explanation
\( I = \frac{1}{2}MR^2 = \frac{1}{2}(20)(0.25)^2 = 0.625 \text{ kg m}^2 \). \( L = I\omega = 0.625 \times 100 = 62.5 \text{ J s} \). \( K = \frac{1}{2}I\omega^2 = \frac{1}{2}(0.625)(100)^2 = 3125 \text{ J} \).