Electricity and magnetism/Electrostatics/Potential Energy

The gravitational potential energy of a body of mass located at the point is equal to where > is the gravitational potential at point . When a body is at rest, its energy is not visible, not actual, because its kinetic energy is zero. When a body at rest is released into free fall, its gravitational potential energy is transformed into kinetic energy. The energy was already present when the body was at rest, but it had not manifested itself, it was only potential. Its transformation into kinetic energy is an actualization of the potential. For a body in free fall, released at rest, its kinetic energy at the end of the movement is the actualization of its gravitational potential energy, initially invisible. It is equal to the work of the force of gravity. So the work of force is the actualization of potential. Potential energy is the potential to cause a force to work. We have potential when we have a force that we can put to work. Energy has many forms: kinetic energy is the energy of a mass due to its speed . Heat is the kinetic energy of atoms and molecules. Gravity energy, electrical energy, and nuclear energy are potential energies that depend on gravitational, electrical, and nuclear forces, respectively. Chemical energy is the electrical energy of atoms and molecules. Light energy is the kinetic energy of photons, the particles of light. The equation for kinetic energy is only a first approximation. A relativistic calculation, in accordance with Einstein's theory, gives a more precise result. The transformation of gravitational potential energy into kinetic energy is an example of conservation of energy. The energy never disappears. When a body loses energy, it always gives it to another body, or it transforms it into another form of energy. A hydroelectric dam transforms the energy of gravity into electrical energy. An electric oven converts electrical energy into heat. A nuclear power plant converts nuclear energy into heat and heat into electrical energy. The same goes for all forms of energy production or consumption. The total amount of energy in the Universe is constant.