🚀 go-pugleaf

In article <230@sri-arpa.ARPA> JDM%SMVL%rca.com@CSNET-RELAY.ARPA writes:
>
>   Maybe someone out there can answer this one quickly. I hope its
>not too fundamental or repetitous.
>
>   Actually, now that I think about it, its really two questions:
>
>   o  Is there a difference between inertial mass and gravitational
>      mass. (I believe that is the same as asking,"is there a 
>      difference between the effects of gravity and the effects
>      of being in an accellerating frame of reference?" But
>      Im sure Im making a drastic generalization.)
There is none.
>   o  Given the old "accellerating-elevator-in-space" experiment,
>      how can one within the elevator tell the whether he is
>      accellerating or under the influence of gravity?
>
Locally, one cannot.  Key word there is locally.  If one can make 
observations over a finite area, then one can tell, if the gravitational
field is varies with position.  That is, if one measures tidal forces,
it is a gravitational field, not acceleration.   This in not a contradiction
of my first answer, or of the equivalence principle -- these state that 
the effects on a point object of a gravitational field and an acceleration
are identical;  however tidal forces can not be measured at a single point.
A formal statement contains incantations about "motions on a geodesic"
and "ability to locally transform the metric into Minkowski form", but
I don't think that such a statement would be particularly enlightening.
>
>    Any correct answer to these questions will end a heated argument
>that is rapidly degenerating into World War III. Can someone save
>the world?
>
>                            Thanks in Advance
>                                Joe


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