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A man spinning in free space can change ...

A man spinning in free space can change the moment of inertia of his body (I) by changing its shape. In this process,

A

He will have to expend some energy to increase I

B

He will have to expend some energy to decrease I

C

He does not have to expend any energy to change I

D

Either (A) or (B) depending on the initial value of I

Text Solution

Verified by Experts

The correct Answer is:
1
Let L=angular momentum `omega`=anugular velocity I=moment of inertia Here, L is conserved `because` `L=Iomega=constant` Kinetic energy =`E=1/2Iomega^2=1/2.I(L/1)^2=L^2/(2I)`.If l decreases, E increases. Hence, energy must be expended.
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