Christophe Grandsire:

> > (And to be even more modern, your E is the Minkowski norm of the
> > energy-momentum four-vector, and in the particle view the energy
> > component is again m c^2).
> >
>Only in the rest frame of the particle. Like I said, nearly nobody ever
>takes m
>to be the relativistic mass. Even Einstein himself rarely used this

Which didn't stop the authors of one of my textbooks at high school using
the relativistic mass m. Evidently, they thought it was nifty to have the
(visually) identical formula p=mv for the [can't recall English term] in
both Classical and Relativistic Mechanics. Or as a physics Prof explained it
to me: "Damn kindergarten teachers who can't realize that p=mv is a
convenient notation for a useful approximation and not a divine decree!".


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