Kinetic energy is defined as the energy of motion. It is the energy that an object possesses due to its movement and is calculated using the formula:
\[ KE = \frac{1}{2}mv^2 \]
where \( KE \) is the kinetic energy, \( m \) is the mass of the object, and \( v \) is its velocity. In contrast, stored energy (often referred to as potential energy) is energy that is held in reserve, and heat refers to the internal energy of a system due to the motion of its particles.