The ability to do work is energy. Energy is found in many forms and is classified as kinetic or potential energy. It is most frequently measured in joules or in British thermal units.
Kinetic energy is energy in motion. Any moving object has energy and is therefore doing work. The formula for kinetic energy is as follows: Kinetic energy equals one-half the mass of an object multiplied by its velocity squared. Kinetic energy does not have a specified direction. Potential energy is stored energy. Potential energy is either gravitational or elastic. An object with potential gravitational energy has the ability to do work based on its height. A ball on the top of a mountain has potential gravitational energy. If a force acts upon it to move it, the energy becomes kinetic in the form of a rolling ball. Elastic potential energy is the potential energy found in a spring or other elastic object. The tauter the spring is pulled, the more potential energy is present. Once the spring is released, the energy is kinetic. These are all types of mechanical energy. Other forms of energy are heat or thermal energy, light energy, chemical energy, nuclear energy and electromagnetic energy.