Re: inertial forces (definition)

[Bob Sciamanda <trebor@VELOCITY.NET>]

Isaac himself would not have made the distinction between inertial and
gravitational mass.  This became most clear when Coulomb's law showed
that, by analogy, Newtonian gravitation involved a "gravitational charge",
conceptually distinct from the inertial mass in F=ma.

However, by Newtonian physics we usually mean the consistent development
of Isaac's beginnings by those who developed and extended his ideas
without contradiction.  Even our wording of Isaac's 3 laws clarifies and
modernizes his statements.

Bob

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor

----- Original Message -----
From: Leigh Palmer <palmer@SFU.CA>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, October 18, 1999 8:32 PM
Subject: Re: inertial forces (definition)


> > 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? He was aware that there is something funny
> about the gravitational force which seemed to act at a distance.
> Today we understand that Newton's third law doesn't hold for
> gravitational forces. (There is no body on which you exert a
> force which is equal in magnitude and opposite in direction to
> the force of gravity which acts on you, even on a nonspinning
> planet.) One must inject the intermediary of a field (which is
> not a body) to save a semblance the appearances. Newton coined
> the word "centrifugal" to describe a similar force. I don't
> believe he ever called it an inertial force.
>
> 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.
>
> Leigh