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A disc is rotating with angular speed CD. If a child sits on it, what is conserved

Answer»

linear MOMENTUM
angular momentum
kinetic energy
potential energy

Solution :When a CHILD sits on a rotating disc, no external torque is introduced. Hence the angular momentum of the system is conserved. But the moment of inertia of the system will increase and as a result, the angular SPEED of the disc will decrease to MAINTAIN CONSTANT angular momentum.
[`because` angular momentum = moment of inertia `xx` angular velocity]


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