Physics - Rotation Question with Solution | TestHub

Angular momentum of a rigid body about a fixed axis is given by

$L=I\omega$

Where$I$is moment of inertia and$\omega$is angular velocity about that axis.

Kinetic energy of body is given by

$K=\frac{1}{2} I{\omega }^2$

$\therefore$$K=\frac{1}{2I}{\left(I\omega \right)}^2=\frac{L^2}{2I}$

$\Rightarrow$$I=\frac{L^2}{2K}$