A fly wheel is a uniform disc of mass 72 kg and radiu 50 cm. When it is rotating at the rate of 70 rpm, its kinetic energy is

A fly wheel is a uniform disc of mass 72 kg and radiu 50 cm. When it i

1.	A fly wheel is a uniform disc of mass 72 kg and radiu 50 cm. When it is rotating at the rate of 70 rpm, its kinetic energy is
Answer» 142 J 242 J 342 J 300 J Solution :Kinetic energy of flywheel , `K = (1)/(2) I omega^(2) = (1)/(2) xx (1)/(2) MR^(2) omega^(2) = (1)/(4) MR^(2) omega^(2)` =`(1)/(4) xx 72 ((50)/(100))^(2) ((2pi xx 70)/(60))^(2) = 241.5 J- 242 J`.