Re: New version of"Does mass increase with speed?" FAQ
- From: "Pmb" <someone@xxxxxxxxxxxxx>
- Date: Mon, 30 Jun 2008 05:53:15 +0000 (UTC)
"harry" <harald.vanlintelButNotThis@xxxxxxx> wrote in message
news:1214575669_35@xxxxxxxxxxxxxxxxxxx
"Nicolaas Vroom" <nicolaas.vroom@xxxxxxxxxx> wrote in message
news:v7d8k.96778$NN3.65424@xxxxxxxxxxxxxxxx
I have a problem with almost any sentence in this document.
Paragraph 1
Sentence #1 Why is this sentence important ?
Sentence #2. How many physicists use the word "mass" differently to
others.
The number of physicists who use "mass" differently does not have any
bearing on whether a given definition can be made to hold in general and
which is logical in all possible circumstances. The branches of physics
in which physicists work in relativity come in three categories, for the
most part anyway
(1) Particle physics
(2) Astrophysics
(3) Theoretical physics
A particle physicist will rarely address classical sitations such as
continuous media. Relativity holds in all classical areas, even when the
matter forms a continuos media. In these cases one has to use a more
general "tool box." Astrophysicists (GRists, cosmologists, etc.) rarely
consider objects which are of laboratory size. For these reasons each of
the branches has its own lingo. But I find it hard to believe that the
second class would use the term "mass density" in a general sense and
have it refer to "rest mass" density or refer to energy density as
measured in the zero momentum frame.
However a theoretical physicist considers both categories 1 and 2. Such
a person even considers such things as the acceleration of a system
consisting only of two charged particles or the momentum of a box
containing a gas of photons. Neither people from 1 or 2 would ever have
cause to consider the right angle lever paradox because such objects
never come up in their lines of work (unless in some strange sense or
analogy etc).
Why Because of this ? Why this sentence ?
IMO there are two concepts: Newton versus Einstein
and within the last SR versus GR.
It would be wrong to imply that one definition applies to Newtonian
mechanics and the other to relativity. In this case the definition lies
outside the theory.
Pete
I doubt that anyone uses a Newtonian concept, as that could not be
maintained with SRT. There are two different ways in which mass has been
redefined in SRT (although each based on a definition of Newton). To make
that clear, it would be better to give a short historical description, and
next explain each definition with its features in its own right.
Regards,
Harald
.
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- Re: New version of"Does mass increase with speed?" FAQ
- From: Nicolaas Vroom
- Re: New version of"Does mass increase with speed?" FAQ
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