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Re: What is weight?

But surely pedagogically we are not going to discuss General Relativity
in a high school or beginning college class. We are talking about
acquiring some workable understanding of basic Newtonian Mechanics.
As such, there are preferred frames, so called intertial frames, where
the meaning is perfectly well defined and measurable.

No we won't be discussing GR in Intro Physics classes ,

BUT

We should _always_ re-state the caveats whenever we simplify so that when
some of the students get to GR etc they won't be confused -- or at least so
that their confusion won't be enhanced: "Now class this is very nearly
true and is ok for general calculations here on Earth, but this needs some
adjustment when we consider that the Earth is rotating (or that it is not
an inertial frame) or when we consider travel near a black hole -- or even
Jupiter -- or even on the Earth if we want to get persnickety."

NEVER give the impression that the simplification is exactly true -- as is
done in most intro classes and texts.

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen