Re: inertial forces (definition)

[Joel Rauber <Joel_Rauber@SDSTATE.EDU>]

Boy, Leigh you are tough   :-)

> > 3) Newtonian viewpoint says, gravity is not one of these
> types of forces
> > since the gravitational is proportional to the gravitational
> mass of the
> > object.
>
> Was that Newton's viewpoint? Did he distinguish inertial and
> gravitational mass?

I do not know.  And for purposes of this discussion it hardly matters.  This
is material that I have inferred from what must be viewed as tertiary or
lower sources, and subsequent understanding of "Classical Dynamics" and the
fact that the there are clearly two uses of the mass concept in what I am
calling the "Newtonian viewpoint".

use 1): mass as gravitational charge, analogous to electric charge, a
property of particles measuring the strength with which they attract each
other gravitationally.

use 2): mass as a measure of inertial properties of an object.  The property
of how hard it is to accelerate said object with a given force.

> I don't
> believe he ever called it an inertial force.

I do not claim that Isaac Newton of Lucasian fame coined that terminology.

> I would appreciate a citation to answer my question. I believe
> I was taught that Newton meant the same kind of mass that he
> spoke of in his dynamics when he formulated his law of gravity.
> The realization that there might be a problem came later, did
> it not? It seems we should not be designating things that are
> not Newtonian as Newtonian.

I do not know the specific time-line of the history of these ideas.  I use
the expressions "Newtonian viewpoint", in what I think is the same way it
has been used in this thread and is used in the common vernacular of the
profession.  Rightly or wrongly.   That is, as a synonomous expression for,
"Newtonian Theory", "Newtonian Dynamics", "Classical Dynamics", "Classical
Mechanics" etc etc, ad nauseum.  It is meant merely as a short way to
designate a certain "self-consistant" theory of dynamics and its
implications that seem to be the way the world operates to a high degree of
approximation in certain regimes where the correspondance limit is
appropriate.  In no way is the adjective "newtonian" meant to imply that the
subsequent coinages of terminology or understanding of the subtleties and
ramifications of the theory are espoused, as evidenced by publication, by
Newton.  The use is honorific, indicated that this great ediface owes so
much to the man.

I'm sure this is overkill as a response, what terminology for the theory
would you prefer?

Naturally it is an interesting point as to whether or not Newton, himself,
distinguished inertial from gravitational mass.  And if so did you publish
anything indicating such an understanding.  I find it hard to believe that
he didn't understand the difference.  I believe that it is entirely possible
that he didn't write about it.  Its my understanding that he didn't write
about several items that troubled him in the principia.  The most obvious
being the whole idea of action at a distance.

Joel