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A child is standing with folded hands at...

A child is standing with folded hands at the center of a platform rotating about its central axis. The kinetic energy of the system is `K`. The child now stretches his arms so that the moment of inertia of the system doubles. The kinetic energy of the system now is

A

`2K`

B

`K/2`

C

`K/4`

D

`4K`

Text Solution

Verified by Experts

The correct Answer is:
B
`KE=(L^(2))/(2l) L` remains constant doubles so `KE` becomes half.
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