Re: definition of weight (again)

["John S. Denker" <jsd@MONMOUTH.COM>]

Chuck Britton wrote:
...
> the 'g' that people really
> experience and geologists really measure.
> It includes the rotational effects of the planet in addition to the
> masses involved.

I completely agree.

==============

More generally, there are several properties we would
like "the" definition of gravity to have, to the
extent possible:
 -- be simple
 -- agree with common usage in ordinary cases
 -- agree with common usage in extreme cases
    (such as weightless astronauts)
 -- agree with modern physics (general relativity)
 -- directly connect Newton's law of universal
    gravitation with the gravity we observe in the lab.

Well, you can have it all _except_ the last one.  If
you insist on g = G M / R^2 then you have to sacrifice
several of the other items on the list.  So don't do that.

Details can be found at
  http://www.monmouth.com/~jsd/physics/weight.htm