Editor’s Note: For further elaboration of this point, see the article on page 40, “Galilean Transformations of Kinetic Energy, Work, and Potential Energy,” by Robert C. Hilborn.

An effective learning strategy is to clarify misunderstandings and correct errors. This letter intends to do both, in regard to my article on Galilean transformations and potential energy.1 

The misunderstanding is generalizing conclusions about frame dependence, drawn from considerations of a single particle, to systems of many particles. While work and kinetic energy do apply to a single particle, potential energy does not. Therefore, if the work done on a particle and its change in kinetic energy are different in different Galilean frames, it is wrong to conclude that potential energy is also frame dependent.

I want to thank Gary B. Adams for helping me realize this, during a poster session conversation, at a recent conference. Potential energy is configuration energy...

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