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 we define a sign as an exact reference, it must include symbol because a symbol is an exact reference too. The difference seems to be that a sign is an exact reference to something definite and a symbol an exact reference to something indefinite.”
—William York Tindall (1903–1981)
“There are old heads in the world who cannot help me by their example or advice to live worthily and satisfactorily to myself; but I believe that it is in my power to elevate myself this very hour above the common level of my life.”
—Henry David Thoreau (1817–1862)