Rotational Kinetic Energy: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Rotational Kinetic Energy. Understanding the underlying formula is key to arriving at the correct answer below:

For a ring rotating about its central perpendicular axis, the moment of inertia is $I = mr^2$. The rotational kinetic energy is defined as $K = \frac{1}{2} I \omega^2$. Substituting $I$, we get $K = \frac{1}{2} mr^2 \omega^2$.