A flywheel is in the form of a uniform circular disc of radius `1 m` and mass `2 kg`. The work which must be done on it to increase its frequency of rotation from `5` to `10 rev//s` is approximately

Options

A. `1.5xx10^(2)J`
B. `3.0xx10^(2)J`
C. `1.5xx10^(3)J`
D. `3.0xx10^(3)J`

Explanation

`W=K_(2)-K_(1)=(1)/(2)I(omega_(2)^(2)-omega_(1)^(2))`
`=(1)/(2)((1)/(2)xx2xx1^(2))(10^(2)-5^(2))(4pi^(2))`
`=150pi^(2)=1.5xx10^(2)J`