Ahad, Disember 09, 2007

Potential Energy

Potential energy From Wikipedia, the free encyclopedia Jump to: navigation , search Potential energy can be thought of as energy sto... thumbnail 1 summary
Potential energy

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Potential energy can be thought of as energy stored within a physical system. This energy can be released or converted into other forms of energy, including 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.
Informally, potential energy exists when there is a
force that tends to pull an object back towards some original position when it is moved. 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 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. The principle of conservation of energy states that energy cannot be created or destroyed, so this energy does not disappear. Instead it is stored as potential energy. If the spring is released or the weight is dropped, this stored energy will reappear as kinetic energy as the restoring forceelasticity in the case of the spring and gravity in the case of the weight — accelerates the object back towards its original position.
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 kind of
force. Technically, any conservative force gives rise to potential energy. For example, the work of elastic force is called elastic potential energy; work of gravitational force is called gravitational potential energy, work of the Coulomb force is called electric potential energy; work of strong nuclear force or weak nuclear force acting on the baryon charge is called nuclear potential energy; work of intermolecular forces is called intermolecular potential energy. Chemical potential energy, such as the energy stored in 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 kinetic energy of random motion of particles and potential energy of their mutual positions.
The phrase 'potential energy' was coined by
William Rankine.[1]

As a general rule, the work done by a conservative force F will be
where ΔPEF is the change in the potential energy associated with that particular force

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