Re: Weight of a moving body - *Jeckyl

"Pmb" <someon@xxxxxxxxxxxxx> wrote in message
news:9dmdnaSFJKtq9hnbnZ2dnUVZ_gWdnZ2d@xxxxxxxxxxxxxx
I believe Jeckly may be interested in this article.
Jeckyl - I mentioned this paper to you

Thanks

On the abuse and use of relativistic mass, Gary Oas, physics/0504110 v2,
21 Oct 2005

Download from http://home.comcast.net/~peter.m.brown/Oas_2005.pdf

Abstract-----------------------------------------------------
The concept of a velocity dependant mass, relativistic mass, is examined
and is found to be inconsistent with the geometrical formulation. This is
not a novel result; however, many continue to use this concept and some
have even attempted to establish it as the basis or special relativity. It
is argued that the oft-held view that formulations of relativity with and
without relativistic mass are equivalent is incorrect. Left as a heuristic
device a preliminary study of first time learners that misconceptions can
develop when the concept is introduced without a basis. In order to gauge
the extent and nature of the use of relativistic mass a survey of the
literature on relativity has been undertaken. The varied and at times
self-contradicting use of this concept points to the lack of clear
consensus on the formation of relativity. As geometry lies at the heart of
all modern representations of relativity, it is urged, once again, that
the use of the concept at all levels be abandoned.
--------------------------------------------------------------

That's pretty much what I've read elsewhere and agrees with what I was
saying. Genreally its better to talk about the Energy of the object, rather
than its relativistic mass, and leave only talk of the proper / invariant /
rest mass when talking about mass. That doesn't mean one cannot define what
one means by inertial / relativistic mass, but whether it is actaully a
useful concept (or whether it ends up a hinderance).

Needless to say that the author is on your side regarding the
"relativistic mass" vs "proper mass" debate. In this article the author
argues to abandon relativistic mass due to the so-called confusion over
the concept or relativistic mass. However I e-mailed posted the link to
you before I actually read it closely. Having read it I found out that the
example the author to justify this so-called "confusion" over rel- mass
that the author asked a set of 164 people of varying backgrounds this
question (paraphrasing here). If a person, "Al", was on a moving train and
his weight in the rest frame of the Earth was 200 lb then if Al measured
his weight while the train was moving would Al measure a value less than,
greater than or equal to 200 lbs. The irony of this question is that the
author automatically assumed that there is no weight change. Presumably he
took a guess himself as what the answer should be. However he is wrong. Al
measures his weight to be greater than 200 lbs. This is because as he
changes his frame of reference relative to the Earth rest frame then he
will measure an increase in the gravitational field and thus his weight
will increase.

But its not the relativistic mass then .. its an effect on weight of the
curvature of the eath etc.

The point is, you cannot detect a change in relativistic mass on yourself
(ie in your own inertial FoR) because you are not moving.
http://www.geocities.com/physics_world/mass_articles.htm
Best regards and I look forward to your opinion on the Oas paper
http://www.geocities.com/physics_world/gr/weight_move.htm

When I can relax a bit, I'll have a look

Thanks for the links though.


.

Relevant Pages

  • Re: Weight of a moving body - *Jeckyl
    ... The concept of a velocity dependant mass, relativistic mass, is examined ... If a person, "Al", was on a moving ... train and his weight in the rest frame of the Earth was 200 lb then if Al ...
    (sci.physics.relativity)
  • Re: Weight of a moving body - *Jeckyl
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