Ah, of course - I should have recognized that from your first post. 
Still impractical outside of a lab, alas.

-Adam

On 8/31/05, Herbert Graf <mailinglist2@farcite.net> wrote:
> On Wed, 2005-08-31 at 14:36 -0400, M. Adam Davis wrote:
> > What exactly is the difference, then?
> 
> As I explained, the force due to acceleration is constant along the
> direction of the acceleration, while gravity is not.
> 
> Consider a rocket with a force meter on the nose, and one on the tail,
> and the rocket is on the earth pointed straight up. On the pad the two
> meters would differ in reading, since the one on the tail is closer to
> the earth then the one on the nose.
> 
> Now consider the same rocket in an environment devoid of any other mass
> (zero gravity). Light that rocket up. The force on the two meters would
> be the same.
> 
> > Or, more appropiately, how do
> > you meaure one without measuring the other?
> 
> AFAIK you can't, and I didn't say you could, force is force.
> 
> > Gravity is a force.
> > Acceleration is a result of force.  Acceleration may be caused by
> > gravity or some other force, or some combination.  Implicit to the
> > definition of both is the concept of mass.  You cannot have gravity or
> > acceleration without mass.  Therefore we measure both gravity (the
> > force), and acceleration (the result of force over time) using mass.
> > I can see that since acceleration involves the variable time it may be
> > possible to differentiate between the two, at least on paper.
> >
> > How does one measure either acceleration or gravity without involving
> > the other?  Or can you point me to research where the difference has
> > been measured?
> 
> I don't think you can, all I said is that the force caused by each is
> different.
> 
> Off hand, if you know the mass of your object and the mass of the Earth,
> any force difference you read between the tail sensor and the nose
> sensor could be inferred to be this part gravity and this part
> acceleration (since you'd have something between the linear line of
> force due to acceleration and the curved line of force due to gravity),
> but I think that would only work when you know the difference in
> direction of your travel vs. the direction of gravity.
> 
> I'm certainly no expert though, it's possible someone out there much
> more cleverer then me has come up with a way to do it, or at least a
> theoretical way of doing it.
> 
> TTYL
> 
> -----------------------------
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> http://repatch.dyndns.org:8383/pic_stuff/
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