Kinetic energy is the energy of motion. An object which has motion - whether it be vertical or horizontal motion - has kinetic energy. There are many forms of kinetic energy:

• vibrational - the energy due to vibrational motion
• rotational - the energy due to rotational motion
• translational - the energy due to motion from one location to another

Let's focus on translational kinetic energy. The amount of translational kinetic energy which an object has depends upon two variables: the mass of the object (related to weight) and the speed of the object. The following equation is used to represent the translational kinetic energy of an object.





This equation reveals that the kinetic energy of an object is directly proportional to the square of its speed. That means that for a twofold increase in speed, the kinetic energy will increase by a factor of four. For a threefold increase in speed, the kinetic energy will increase by a factor of nine! So we see that kinetic energy is dependent upon the square of the speed.