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A solid sphere is rotating about a diame...

A solid sphere is rotating about a diameter at an angular velocity `omega`. If it cools so that its radius reduces to `1//n` of its original value, its angular velocity becomes

A

`omega /n`

B

`(omega )/(n ^(2))`

C

`n ^(2) omega`

D

`n omega`

Text Solution

Verified by Experts

According to aw of conservation of angular momentum is no external torque is acting upon a body about an axis, then the angular momentum of the body
`L = I omega =`constant
`implies I _(1) omega _(1) = I _(2) omega _(2)`
Also `1= (2)/(5) MR ^(2)` for a solid sphere,
Given, `R _(1) = R, R _(2) = (R )/(n )`
`therefore (2)/(5) MR ""^(2) omega _(1) = (2)/(5) M ((R)/(n )) ^(2) xx omega _(2)`
`implies omega_(2) = n^(2) omega _(1) = n ^(2) omega `
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