A fly wheel of mass 60 kg and radius 40 cm is revolving at 300 rpm, then its rotational K.E. isA. `(48)/(pi^(2))J`B. `480 pi J`C. `(48)/(pi)J`D. `240 pi^(2)J`

A fly wheel of mass 60 kg and radius 40 cm is revolving at 300 rpm, th

1.	A fly wheel of mass 60 kg and radius 40 cm is revolving at 300 rpm, then its rotational K.E. isA. `(48)/(pi^(2))J`B. `480 pi J`C. `(48)/(pi)J`D. `240 pi^(2)J`
Answer» Correct Answer - D K.E. of rotation `=(1)/(2) I omega^(2)` `=(1)/(2)((1)/(2)mR^(2))omega^(2)` `=(1)/(4)mR^(2)(2pi n)^(2)=pi^(2)n^(2)m R^(2)` `= pi^(2)((300)/(60))^(2)xx60xx(0.4)^(2)=240 pi^(2)J`

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A fly wheel of mass 60 kg and radius 40 cm is revolving at 300 rpm, then its rotational K.E. isA. `(48)/(pi^(2))J`B. `480 pi J`C. `(48)/(pi)J`D. `240 pi^(2)J`

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