Reference Level
The potential energy is a function of the state a system is in, and is defined relative to that for a particular state. This reference state is not always a real state, it may also be a limit, such as with the distances between all bodies tending to infinity, provided that the energy involved in tending to that limit is finite, such as in the case of inverse-square law forces. Any arbitrary reference state could be used, therefore it can be chosen based on convenience.
Typically the potential energy of a system depends on the relative positions of its components only, so the reference state can also be expressed in terms of relative positions.
Read more about this topic: Potential Energy
Famous quotes containing the words reference and/or level:
“If Hitler invaded hell I would make at least a favourable reference to the devil in the House of Commons.”
—Winston Churchill (1874–1965)
“For him nor deep nor hill there is,
But all’s one level plain he hunts for flowers.”
—Unknown. The Thousand and One Nights.
AWP. Anthology of World Poetry, An. Mark Van Doren, ed. (Rev. and enl. Ed., 1936)