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Particle? -- Mass?



Correct. I believe John Denker already explained this in terms of the
relativistic relationship between energy and momentum for both particles
with nonzero and with zero mass. (He tries to keep the old nomenclature by
qualifying the term 'mass' with the modifier 'rest' to prevent any
confusion by someone who had, unfortunately been led to believe by their
training that 'mass' means something other than 'rest mass').

I am a bit troubled by this usage -- I don't see a problem at all by trying
to distinguish between some sort of "rest mass" and some other sort of
"mass". Mass is a property of the system/particle. is it not? If
something is done to the system to change its energy, we don't make a big
deal about some sort of "rest energy" as distinguished from a "traveling"
energy do we? "Mass" is not some sort of fluid the system "contains", it
is a property of the system which can be diminished and augmented -- just
as can the energy of the berg.

I tow an iceberg into NY Harbor to extract fresh water (a distinct
possibility one day) As the berg melts it clearly gains energy -- it
likewise gains mass.

It would be silly to say things like "rest mass" of the iceberg as if it
were the only value which mattered -- or say "rest energy" as if there were
something special about that value.

Just me over here in my little corner.

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen