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A copper ball of mass m=1 kg with a radi...

A copper ball of mass `m=1 kg` with a radius of `r = 10 cm` rotates with angular velocity `omega= 2 rad//s` about an axis passing through its centre. What work should be performed to increase the angular velocity of rotation of the ball two fold?

Text Solution

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The correct Answer is:
2
From work - energy theorem
`Delta K.E. = (1)/(2).(2)/(5) m [r^(2) omega_(2)^(2) - r^(2)omega_(1)^(2)]`
`= (1)/(5) xx 1 [((1)/(10))^(2)] [4^(2) - 2^(2)] J = 2.4 xx 10^(-2) J`
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