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A disc is rotating with angular speed CD...

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

A

linear momentum

B

angular momentum

C

kinetic energy

D

potential energy

Text Solution

Verified by Experts

The correct Answer is:
B
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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Knowledge Check

  • A disc is rotating with angular velocity omega . If a child sits on it, what is conserved?

    A
    Linear momentum
    B
    Angular momentum
    C
    kinetic energy
    D
    Moment of inertia

  • A disc is rotating with an angular speed of omega . If a child sits on it, which of the following is conserved

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    Kinetic energy
    B
    Potential energy
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    Linear momentum
    D
    Angular momentum

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    A
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