It is a consequence of the principle of conservation of momentum that, if the interaction between two particles can be described by a potential energy function, this should be a function only of their...It is a consequence of the principle of conservation of momentum that, if the interaction between two particles can be described by a potential energy function, this should be a function only of their relative position, that is, the quantity x1−x2 (or x2−x1), and not of the individual coordinates, x1 and x2, separately 4 . The example of the spring in the previous section illustrates this, whereas the gravitational potential energy example shows how this can be simplif…
