Q. A flywheel rotating about a fixed axis has a kinetic energy of $360\ joule$ when its angular speed is $30\ rad/sec$. The moment of inertia of the wheel about the axis of rotation is
A) $0.6\ kg \times m^{2}$
B) $0.15\ kg \times m^{2}$
C) $0.8\ kg \times m^{2}$
D) $0.75\ kg \times m^{2}$
Explanation
(c) $\frac{1}{2}I\omega^{2} = 360 \Rightarrow I = \frac{2 \times 360}{(30)^{2}} = \frac{2 \times 360}{30 \times 30} = 0.8kg \times m^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.