Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Rotational kinetic energy is the energy possessed by a rotating object due to its angular motion. It is given by the formula $KE_{rot} = \frac{1}{2}I\omega^2$, where $I$ is the moment of inertia and $\omega$ is the angular velocity.
5 Must Know Facts For Your Next Test
Rotational kinetic energy depends on both the moment of inertia and the square of the angular velocity.
The moment of inertia, $I$, depends on how an object's mass is distributed relative to the axis of rotation.
Angular velocity, $\omega$, is measured in radians per second (rad/s).
Rotational kinetic energy can be converted into other forms of energy, such as translational kinetic energy or potential energy.
In systems with both rotational and translational motion, total kinetic energy is the sum of translational kinetic energy ($KE_{trans} = \frac{1}{2}mv^2$) and rotational kinetic energy.
A measure of an object's resistance to changes in its rotation rate. It depends on the mass distribution relative to the axis of rotation.
$\omega$ (Angular Velocity): The rate at which an object rotates or revolves around an axis; measured in radians per second (rad/s).
$KE_{trans}$ (Translational Kinetic Energy): The energy due to linear motion, calculated as $KE_{trans} = \frac{1}{2}mv^2$, where $m$ is mass and $v$ is linear velocity.