Inertia or the "amount of substance"

["Miguel A. Santos" <msantos@ETSE.URV.ES>]

  There is indeed a problem in mixing both ideas, as I see it.
I'd say that the conception of mass "as the amount of substance which can
not be changed without taken somehting away, or adding" may be a
misconception*. Namely, as I move faster and faster, relative to someone
else, I see her/him getting fater and fater, and she/he is not eating that
much. It is the inertia which is increasing.

  What do others thing?
  What about for a charge if one takes into account the radiative
reaction? Could this also be adscribe to a change in its 'm'? The
Abraham-Lorentz treatment doesn't seems to imply this.

 Miguel A. Santos
 msantos@etse.urv.es


*Altough fine for a child who comes across 'm' for the first time


On Fri, 12 Nov 1999, Miguel A. Santos wrote:

> On Thu, 11 Nov 1999, Ludwik Kowalski wrote:
>
> > inertia and mass. Why? Because of the language. In common
> > terms the mass is the amount of substance which can not be changed
> > without taking something away, or adding. In an introductory course
> > I do not reject this naive picture. The definition of m in terms of F/a
>
>  Any way, I don't see any problem in mixing both ideas, inertia and amount
> of substance when talking about F/m, or may be there is some problem...?
> >