Re: Causation in Physics: F=ma

["Folkerts, Timothy" <FolkertsT@BARTONCCC.EDU>]

I'm not sure I understand a couple of the points here (which is rare for
John, who usually provides lucid explanations!)  Let me paraphrase the
paragraph.

> I have a particle of mass (m) in a centrifuge.
I have a satellite of mass (m) in an orbit.

> Everything in the centrifuge is subject to an
> acceleration (a), perhaps 10,000 Gees.
Everything in that orbit is subject to perhaps 0.5 Gees

> I can calculate the force on the particle according
> to the formula F=ma.
Ditto.

> Do you really expect anybody to believe that the force
> causes the acceleration?
Do you really expect anyone to believe that the gravitational force causes
the acceleration?

Well, yes, I do expect that (at least in a Newtonian point of view).
Are you saying that there is something special about the centrifuge?  Or
that all circular motion problems could better be thought of in terms of
"accleration fields" instead of forces?   Or something else?


> The acceleration is the same even if there is no particle at all!
This is an interesting concept.  Can "nothing" have a position or a speed or
an acceleration?  Don't you need "something" as a reference point?  How do
you measure the acceleration of "nothing"?  On the other hand, I have no
trouble talking about E fields without needing a particle to interact with
it.  This bears a little more thought.

Tim Folkerts.