alleryStart learning →A disc spins at 60 rpm. With no external torque, its moment of inertia falls to one quarter. New speed in rpm?
A15
B120
C240
D30
Answer & Solution
Correct answer: C. 240
Angular momentum is conserved, so a quarter of I means four times the speed: 240 rpm.
Keep practising Rotational Dynamics
Browse all Rotational Dynamics questions for MHT-CET, or explore more Physics topics.
Related questions
For a slender rod (mass M, length L), I about the perpendicular through its middle isMoment of inertia of a uniform solid ball (mass M, radius R) about a diameter isA ring of mass 2 kg has I = 2 kg m² about its axis. Its radius of gyration isA wheel of I = 4 kg m² gains angular acceleration 2.5 rad/s². The torque in N m isA force of 20 N acts at a perpendicular distance of 0.3 m from the axis. The torque in N mA wheel has I = 0.5 kg m² and spins at 4 rad/s. Its angular momentum in kg m²/s isA body with I = 2 kg m² spins at 10 rad/s. Its rotational kinetic energy in joules isTwo particles of 2 kg at 1 m and 3 kg at 2 m from an axis. Their moment of inertia in kg m