Re: inertial forces (definition)

[brian whatcott <inet@INTELLISYS.NET>]

In considering Joel's cautionary note, I recalled that I had quoted
 some fragments of Book 3, System of the World, without paying
attention to Newton's introduction to that book, where he mentions
 his original intent (and manuscript) was to provide a popular
treatment "that it might be read by many..." but afterwards he
repented, for fear of giving rise to disputes.

He then reduced this book to the form of Propositions and suggests
prior reading of the Principles: if not all of them as being too
demanding, then at least the Definitions, the Laws of Motion, and
the first three sections of the first book.

 Taking him at his word, I see that in the opening Definitions of
Book 1, the first mentions mass, the second the motion (momentum)
and the third discusses the "vis insita", the innate force of matter
 which
"is a power of resisting, by which every body, as much as in it lies,
 continues in its present state, whether it be of rest or of moving
uniformly forwards in a right line......Upon which account, this vis
 insita may, by a most significant name, be called inertia
(vis inertiae) or force of inactivity."

So while Newton may not have distinguished inertial from gravitating
masses, he does write of distinct gravitating and inertial forces,
as I have shown here.

Brian



At 11:08 10/19/99 -0500, you wrote:
> I'm not sure I would make such a bold statement as the one below.  There is,
> of course, a difference between whether Isaac would've made the distinction,
> say in published and carefully written works...
> Joel
> > 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"...
> > Bob Sciamanda

> > > Was that Newton's viewpoint? Did he distinguish inertial and
> > > gravitational mass? ...
> > > Leigh





brian whatcott <inet@intellisys.net>
Altus OK