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:
“In writing these Tales ... at long intervals, I have kept the book-unity always in mind ... with reference to its effect as part of a whole.”
—Edgar Allan Poe (1809–1849)
“Architecture might be more sportive and varied if every man built his own house, but it would not be the art and science that we have made it; and while every woman prepares food for her own family, cooking can never rise beyond the level of the amateur’s work.”
—Charlotte Perkins Gilman (1860–1935)