Re: Weight of a moving body - *Jeckyl

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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.

How so. The author was using his world view of mass and he made a
porediction with that view that was wrong.

But not wrong in a way that shows his view was wrong (ie that talking about
relativistic mass is not terribly useful, as it is observer dependant). You
don't really need to talk about relativistic mass as a separate
calculation/measurement.

[snip]
Genreally its better to talk about the Energy of the object, rather than
its relativistic mass, ...

The two are only proportional under the circumstance where it refers to
the mass of a closed system. It doesn't hold in general (i.e. external
stresses acting on the body)

Yes .. and it is generally better to talk about the Energy .. the
relativistic mass isn't terribly useful to talk about .. Energy and momentum
are, however.

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

What is it that you think that weight means?

Weight is not mass

Weight is the force required to overcome the gravitational force in order
to have an object remain at rest in the field/frame of reference in
g-field. This is called the passive gravitational mass. But no matter who
measures it it will have increased.

The point is, you cannot detect a change in relativistic mass on yourself
Sure you can.

But not in an inertial frame as I said.

The observer in the moving frame will definitely read an increase in
weight. This will be due to an increase in the gravitational field as
recorded by the moving observer. The observer at rest will attribute the
increase in weight as an increase in passive gravitational mass.

(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.

I look forward to talking to you about this or any topic if you wish. I'm
simply trying to avoid the same old arguements start up. I'm fairly suire
that it will happen any way though. But I can simply ignore them since in
all likelyhood they will be telling me the same thing they have over the
last 7 years.

Likewise.


.

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