Question

If is the angular momentum is $L$ and $I$ is the moment of inertia of a rotating body, then $\frac{L^2}{2I}$ represents its ____________

• A. rotational PE
• B. total energy
• C. rotational KE
• D. translation KE

Answer 1

The correct option is C rotational KE

For rotating body,

given that:

Moment of inertia = $I$

We know that,

Angular momentum $L=I\omega$

Now,

Rotational kinetic energy = $\frac{\left(I{\omega }^2\right)}{2}$

So, rotational kinetic energy = $\left(\frac{L^2}{2I}\right)$

Hence, $\left(\frac{L^2}{2I}\right)$ is the rotational kinetic energy.