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A uniform disk of mass 300kg is rotating...

A uniform disk of mass `300kg` is rotating freely about a vertical axis through its centre with constant angular velocity `omega .` A boy of mass `30kg` starts from the centre and moves along a radius to the edge of the disk. The angular velocity of the disk now is

A

`(omega_(0))/(6)`

B

`(omega_(0))/(5)`

C

`(4omega_(0))/(5)`

D

`(5 omega_(0))/(6)`

Text Solution

Verified by Experts

The correct Answer is:
D
As `Sigma tau =0` , angular momentum remains conserved `:`
`:. L=(0+(300R^(2))/(2))`
`omega_(0)=((300R^(2))/(2)+30R^(2)).omega`
`=150 omega _(0)=180 omega`
`rArr omega = 5/6 omega _(0) Ans. `
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