On Jan 1, 11:44*pm, Pentcho Valev wrote:
On Jan 2, 5:54 am, Tom Roberts wrote in
sci.physics.relativity:

Jenny wrote:
On Jan 1, 3:33 pm, eric gisse wrote:
A force is conservative if F = -grad (some potential).
[...] The "-" sign makes no
difference to the "numerology".

Not true. The minus sign is ESSENTIAL. Otherwise there would be a force pushing
an object to a higher energy state, and all sorts of fundamental physical laws
would be violated. For example, with such a "force" it would be dead easy to
build a perpetual motion machine that generated arbitrary amounts of free energy.

Honest Roberts, a perpetual motion machine that generates an unlimited
amount of energy out of nothing is a direct corollary of Einstein's
1905 false light postulate. The very long rod trapped inside a very
short container would exert such a force on the doors of the container
that Einsteinians, by harnessing this force, would be able to solve
all energy problems of humankind:

http://groups.google.com/group/sci.p...rowse_frm/thre...
EINSTEINIANA AS PERPETUUM MOBILE

Pentcho Valev


Or, simply use a wee bit of vacuum if you wanted to move something
like Earth or that of our moon(Selene).

~ BG