The kinetic energy is given by
E=21Iω2=(2IL2)
It is given that the new moment of inertia
I′=3I
Clearly, the final kinetic energy is
Ef=2I′L2=6IL2⇒Ef=(3E)
JEE Main 2023 — Physics Mechanics
A circular plate is rotating in horizontal plane, about an axis passing through its centre and perpendicular to the plate, with an angular velocity ω. A person sits at the centre having two dumbbells in his hands. When he stretched out his hands, the moment of inertia of the system becomes triple. If E be the initial Kinetic energy of the system, then final Kinetic energy will be xE. The value of x is
Held on 11 Apr 2023 · Verified 6 Jul 2026.
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