A circular disc is rotating in a horizontal plane about vertical axis passing through its centre without friction with a person standing on the disc at its edge. If the person gently walks to centre of the disc, then its angular velocity:
A
increases
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B
decreases
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C
does not change
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D
becomes zero
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Solution
The correct option is A increases No external torque is present so, Angular momentum will remain conserved. ∴L1=L2 As the man walk towards the center of the disk, the moment of inertia will decrease and because angular momentum is constant, the angular velocity will increase.