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Re: Mass



Hi Jim,
Continuing our exemplary discussion aimed at discovering; What is the real
question.

You seem to be asking generally about the subject of mass and energy. One
way to characterize energy is as the fourth component of the
energy-momentum four-vector. So might your question be: why do we want to
deal with 4-vectors?
Best,
Jack


On Wed, 20 Oct 2004, Jim Green wrote:

The first step in responding to a question is to ask myself, "Did I
understand the question?" IF I think I did, then I'll try a question or
comment to check out my understanding, because until I've done that the
questioner and I are not in communication. For example, since I know that
Jim invariably has an agenda in mind when he asks a question, and I'm
curious about the agenda, I'll respond as follows:

Ok I will confess. The perceptive Jack Uretsky has found me out. And I am
flattered.

I have been going over some papers re relativistic mass and wondering why
there is a vigorous debate about the concept. Just what is E and m in
E=mc^2. After some ongoing thought over several years I have concluded
that E and m are the same thing ie not E equals m but E IS m.

Then my mind wonders about the tendency of the group to view E as a
substantive fluid. And then my mind wanders to the question of whether the
group views m as a substance. I thought that I would probe this issue.

Lo and behold some -- if not many/most -- do. Some want m to be protons
and neutrons. Only one or two have said that m is an abstract invented
property of a system.

In addition no one as yet has addressed photons. Light is bent by huge
massive bodies as though massive photons (also invented creatures) were
passing through a gravitational field (what ever that is). I wonder about
this as well.

Jim, what have you got against Feynman's discussion in I-9-1 of
the Feynman lectures?

Jack, inertial mass is just fine for basic intro problems, but it doesn't
give me much insight into E=mc^2 and complimentary ideas. Neither does it
help me much with GR.

Besides some colleagues continue to urge me to write a paper re energy and
I don't trust Feynman's views nor those of Bill Ney the Science Guy. On
the other hand I may be far too old for this sort of thing. Everyone seems
to be into HS physics. <g>

Now I have confessed -- but I don't seek absolution.

Jim


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



--
"Trust me. I have a lot of experience at this."
General Custer's unremembered message to his men,
just before leading them into the Little Big Horn Valley