6.1 Rotational Kinetic Energy

Just like translational kinetic energy, objects that are rotating also have some kinetic energy. The rotational kinetic energy of a rigid body is simply the sum of all the individual kinetic energies of each of the individual particles that are in rotation. Rotational kinetic energy is a scalar, measured in joules (J), and represented as ${K_{rot}}$.

Rotational and translational kinetic energy are 2 separate things that must be found individually. Translational kinetic energy is found with the |velocity of the center of mass| of the object whilst the rotational kinetic energy is found with the |angular velocity| around the center of mass of an object. An object can have one type of kinetic energy but not the other. For example, a rotating body with a stationary center of mass will have rotational kinetic energy but not translational kinetic energy. The |total kinetic energy| of a system is simply a combination of its rotational and translational kinetic energies.