Question

A fly wheel rotating about fixed axis has a kinetic energy of $360$ joule when its angular speed is $30$ radian/sec. The moment of inertia of the wheel about the axis of rotation is

• A. $0.6\, kgm^2$
• B. $0.15\, kgm^2$
• C. $0.8\, kgm^2$
• D. $0.75\, kgm^2$

Answer 1

Answer: (C)

$K.E. = \frac{1}{2}I\omega^2$
$I=\frac{2K.E}{\omega^2}=\frac{2 \times 360}{30 \times 30}=0.8 \,kgm^2$