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en:Potential energy can be thought of as en:energy stored within a physical system. This energy can be released or converted into other forms of energy, including en:kinetic energy. It is called potential energy because it has the potential to change the states of objects in the system when the energy is released.
The phrase 'potential energy' was coined by en:William Rankine.[1]
[edytuj] Overview
Potential energy exists when there is a en:force that tends to pull an object back towards some original position when the object is displaced. This force is often called a restoring force. For example, when a spring is stretched to the left, it exerts a force to the right so as to return to its original, un-stretched position. Or, suppose that a weight is lifted straight up. The force of en:gravity will try to bring it back down to its original position. The initial steps of stretching the spring and lifting the weight both require energy to perform. According to the principle of en:conservation of energy, energy cannot be created or destroyed; hence this energy cannot disappear. Instead it is stored as potential energy. If the spring is released or the weight is dropped, this stored energy will be converted into en:kinetic energy by the en:restoring force — elasticity in the case of the spring, and en:gravity in the case of the weight.
The more formal definition is that potential energy is the energy of position, that is, the energy an object is considered to have due to its position in space. There are a number of different types of potential energy, each associated with a particular type of en:force. More specifically, every en:conservative force gives rise to potential energy. For example, the work of elastic force is called elastic potential energy; work of en:gravitational force is called gravitational potential energy, work of the en:Coulomb force is called electric potential energy; work of en:strong nuclear force or en:weak nuclear force acting on the en:baryon en:charge is called nuclear potential energy; work of en:intermolecular forces is called intermolecular potential energy. Chemical potential energy, such as the energy stored in en:fossil fuels, is the work of Coulomb force during rearrangement of mutual positions of electrons and nuclei in atoms and molecules. Thermal energy usually has two components: the en:kinetic energy of random motion of particles and potential energy of their mutual positions.
As a general rule, the work done by a conservative force F will be
where ΔPE is the change in the potential energy associated with that particular force. The most common notations for potential energy are PE and U. It is important to note that en:electric potential (commonly denoted with a V for voltage) is not the same as electric potential energy.
