### potential energy

**(PE)**
(an object's energy that can be released)

**Potential energy** is energy that can be released, e.g.,
to push on something, basically energy that is not kinetic energy.
Everyday examples include the energy in a spring under tension,
or the energy in a weight some distance above the Earth,
both of which have been used in mechanical clocks to provide the
energy to make them run. Chemical and nuclear energy are also
potential energy (or, at minimum, includes some).

There is potential energy in any two objects sharing a mutual
force, e.g., gravity, so the Earth's position relative
to the Sun has a certain amount, or an atom's electron's
position relative to the nucleus. For items attracting each
other, a common convention is to list the potential energy
as negative, the amount of energy required to pull them
completely apart. In the case of gravity, this equals the
kinetic energy the item would need to travel at **escape velocity**.
In the case of an atom's electric force, this equals the
energy necessary to ionize the atom, i.e., draw the electron
completely away from the nucleus. (In both cases, the
force is there at any distance, the velocity/energy is
just enough to put the one item on a course where it would
never slow enough to return, if there were no other
influences.)
The "negative energy convention" makes the math of summing kinetic
and potential energy both before and after some activity show the
conservation of energy: so the resulting sums are equal.

(*physics,energy*)
**Further reading:**

http://en.wikipedia.org/wiki/Potential_energy

**Referenced by pages:**

accretion

Bohr model

core collapse

entropy (S)

escape velocity (V_{e})

Fermi sea

globular cluster (GC)

gravitational collapse

gravitational potential (Φ)

Hamiltonian

helium rain

homologous collapse

Jeans parameter (λ)

Kelvin-Helmholtz mechanism

Kelvin-Helmholtz timescale (KH timescale)

tidal Q

virial parameter

virial theorem

Wigner crystal

Index