Re: A new SR principle!


"Gerald L. O'Barr" <globarr@xxxxxxxxx> wrote in message
news:1175535543.637334.112690@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Subject: Re: A new SR principle!

harry <harald.vanlintelButNotT...@xxxxxxx> wrote:
Gerald L. O'Barr" <globarr...@xxxxxxxxx> wrote:
A new SR principle!

Let us accept a new SR principle:

In SR, there are limits to certain types of
mechanical motions!

harry <harald.vanlintelButNotT...@xxxxxxx> wrote:
That's the OLDEST special relativity principle
(1904 perhaps?)...

O'Barr comments:
Well, that is music to my ears, because what I am
saying is correct. And yet everyone else is saying I
am wrong. Why do you think people say that I am
wrong, when you say it is actually the oldest thought
of all?


O'Barr wrote:
In Newtonian physics, there are limits to
mechanical motions. When you want to spin a disk,
you are limited by the stresses and strains that
can
be permitted. If you spin something too fast, it
will fly apart. Now these limits are not limits
in the actual physics, but due to the limits in
the properties of the materials being used. I
know of no limits in the actual physics.
Now of course, in SR, similar property limits
would have to exist. But I want to introduce to
you today that there are other limits, real
limits, limits based upon the physics itself. Let
us think for a few minutes about this problem.
In SR, when you spin a disk, the circumference
that is moving with a rim velocity of v, must
shirk by a ratio of (1-v^2/c^2)^0.5 to one.

harry <harald.vanlintelButNotT...@xxxxxxx> wrote:
Perhaps you wanted to say something like "tries to
shrink"?

O'Barr comments:
You are absolutely correct! The circumference
wants to get smaller, but the radius wants to remain
the same. And thus some stresses and stains must
appear within the material, and which 'tendency' is
going to win the most might depend on the design and
the material properties of the material being used.
At the minimum, some reduction in radius must occur.
I am aware that some have solved this problem by
having a thin disk, and allowing it to bend out of
plane, which allows the circumference to shorten,
with the radius remaining the same length. But this
solution, as stated, also fails as a mechanical
design since it directly shows that as a working
machine, such a solution would instantly bring the
mechanics to a halt. For example, if this rotating
disk was a gear, its teeth would no longer match the
teeth of the next gear, if it bended out of plane as
might be required for such a solution.
All of this is of course only speaking
relativistically. In actual fact, since there would
be large centrifugal forces at work, the whole disk
could expand, and not bend back upon itself. But we
are ignoring all these details. We could say that we
are considering massless materials, that take the
shape required by SR only.

O'Barr wrote (about these rotating disks):
But the length
of the radius must remain unchanged. This is a
mechanical problem, and will force there to
eventually be a failure, even if the material
theoretically had sufficient strength to remain
together.

harry <harald.vanlintelButNotT...@xxxxxxx> wrote:
?? No failure but an equilibrium, as became clear
after Ehrenfest presented it as a paradox.
See for example Lorentz, Nature vol.106, pp.793-
795: the relativistic contraction is 1/4 of the
above-mentioned coefficient (and no, gamma is not
"required" by SRT).

O'Barr comments:
Be sure to note that my 'failure' is failure as a
working machine. Gears or friction contacts would be
impossible to maintain in any normal design if such
actions by individual parts were to actually occur.
See how I worded it below:

O'Barr wrote:
Note carefully how this failure has to be
defined: There must be a failure, either in what
is required by SR as given in the relationship
stated above, or in the material, or in the
mechanical shape required by the machine design.
If this disk had to maintain close tolerances
with other parts, especially non-moving parts such
as being confined in a closure of any type, there
would be problems. Therefore, depending on the
design, real physical limits will exist in the
physics itself.

harry <harald.vanlintelButNotT...@xxxxxxx> wrote:
I(n) practice, there are no such problems (the disk
would explode before any relativistic contraction
would be measurable, regretfully).

O'Barr comments:
However correct this is, it does not prevent what
I have said from being true: There is a theoretical
limit, in SR, for certain types of mechanical
motions. This really is important. It will cause us
to have to finally understand that SR is only math,
and many other things will have to be considered
before our real physical reality can be correctly
understood.

O'Barr wrote:
To continue these thoughts, if you were observing
a high velocity object, moving so fast that there
were a 50% shortening in the lengths in the
direction of motion, what problems would then
occur? If on this fast moving object there was a
disk rotating so that in one radius direction, this
shortening would be required, and at 90 degrees it
would return to its normal dimensions, then the
speed of rotation would become interesting. For
every rotation of the disk, the mass on the rim
would have to experience violent motions in and
out, and this could set up vibrations or
oscillations that would interfere with most
mechanical functions.

harry <harald.vanlintelButNotT...@xxxxxxx> wrote:
Almost certainly not since that would imply that
the Lorentz transformations are not valid. I suppose
that you did not calculate it - right?

O'Barr comments:
I did not calculate it? I calculated what would
be measured in my own rest frame. And in my own rest
frame, I do calculate that the length of a moving
object becomes less in the direction that it is
moving. Therefore, if this moving object is a
rotating object, and in its rotation it has a radius
that at one point of the rotation lies in the
direction of motion, and in another position of its
rotation it lies perpendicular to its motion,
then parts of this rotating object would have to be
going through expansions at one point, and going
through contractions instantly thereafter, as it
rotated.

Sure - so far no problem. The problem starts when you claim that such will
lead to mechanical instabilities. That it is known to be correct *if* only
length contraction would occur (as measured in your frame). However, such is
not the case. As measured in the moving frame, the physics will be most
probably standard physics. In order to conveniently verify that this is so
(at least in theory) you may consider to do a mapping with -for example- a
Lorentz transformation. :-)

This is not just a guess on my part. Any physical
object that was rotating in such an orientation will
have to see such events.

Here you assume that events will be seen on a rotating object that according
to most people will not be seen on that object.
As it's you who makes extraordinary claims that are hard to verify (the
calculaion is *not* simple), I guess that it's also up to you to show it, if
you want people to invest time in it. As long as you don't show your
calculations, what alternative do I have than to continue to assume that
this *is* "just a guess on your part"?

And such events are not
good, in terms of a working machine.

Look, Harry. I am not just talking. What I say
is real, and it is important, and we must not run and
hide behind nasty remarks that others are doing.
Thanks for being so kind in your own responses.

You're welcome. This kind of errors has been made by renowned scientists in
the past. See for example Michelson's error of 1881
(http://web.archive.org/web/20060422033109/http://www.aip.org/history/gap/PDF/michelson.pdf
, bottom of p.334) and also Trouton and Rankine,
http://en.wikipedia.org/wiki/Trouton-Rankine_experiment .

Now please note, when we do allow ourselves to
re-establish ourselves in the real physical world (an
LET type of world), we have to know that there are
differences between mechanical actions of objects
that have small absolute motions and objects that
have high absolute motions. SR shows no differences,
but in LET, we know that there are differences.

I'm afraid that I don't know that. :-)

And
a working object that has small absolute motions will
continue to work, no matter how fast any observers
might be moving past them. But if a rotating object
is itself actually moving at a high linear velocity,
it is under these physical conditions where variances
will begin to be noted. This is what we must be
directing our minds to, and so far I have not seen
one person grasp the points being made.

I contemplated these points a long time ago (possibly triggered by one of
your postings), but I found no support for such claims.

An object can be observed to have a distorted
shape for more than one reason: It really is
distorted, or the tools being used to measure it are
distorted. Usually both are involved to one degree
or another. But what I am saying is that when any
distortion is actually of the real part, then its
acts will not be good. Certainly, for those
mechanical machines where their distortions are only
in the tools we are using to measure it, they could
continue to function. So to be as clear as possible:
Some failure modes exist in all cases, but the actual
nature of these failure modes can and do change with
the absolute velocity that exists.

Thanks for reading.
Gerald L. O'Barr.

Regards,
Harald


.

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