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

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. The work should be performed to increase the angular velocity of rotation of the ball two fold is.

Text Solution

Verified by Experts

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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