When an object rotates, it possesses rotational kinetic energy — the energy associated with its spinning motion. Just like a moving object has translational kinetic energy due to its linear motion, a rotating object has energy because different parts of it are moving in circles around an axis.
The rotational kinetic energy depends on:
- The object’s moment of inertia (how mass is distributed relative to the axis of rotation)
- The angular velocity (how fast it spins)
Key points:
- The more mass an object has, and the farther that mass is from the axis of rotation, the greater its moment of inertia — and thus, the more energy it takes to rotate it.
- Rotational kinetic energy contributes to the total kinetic energy of an object that is both rotating and translating (like a rolling wheel).
Understanding this concept is vital in fields like mechanical engineering, robotics, and physics, where rotating systems like gears, turbines, and wheels are common.