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Re: a relativity question



John Mallincrodt wrote:
" . . . No; an elevated mass does not "have" more energy despite the
implications of standard textbooks (and not to mention the usefulness
of that gentle subterfuge in many common situations.) Gravitational
potential energy is a property of a *system* of interacting masses. . . ."

Which system? The car/earth system is part of the earth/moon system, is
part of the earth/sun system, is part of the solar system, is part of the
milky way system, is part of . . . the universe. Thus the mass of the
universe increases, but not the mass of its parts!

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor


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This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.