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…

Question

A circular plate is rotating in horizontal plane, about an axis passing through its centre and perpendicular to the plate, with an angular velocity &#969; . 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 E x . The value of x is

Aicharya · Accepted Answer

The kinetic energy is given by E = 1 2 I &#969; 2 = L 2 2 I It is given that the new moment of inertia I ' = 3 I Clearly, the final kinetic energy is E f = L 2 2 I ' = L 2 6 I &#8658; E f = E 3

A circular plate is rotating in horizontal plane, about an axis passing through its centre and perpendicular…

Solution