Re: TomTom's stupidity (re: was always TomTom's stupidity)


Daryl McCullough wrote:
> schoenfeld1@xxxxxxxxx says...
>
> >Daryl McCullough wrote:
>
> >> I did no such thing. What I claimed was that *if* you accelerate
> >> both ends of a rod in such a way that the accelerations are
> >> equal *as* measured in the original inertial reference frame,
> >> *then* the length of the rod will change, as measured in its
> >> own reference frame.
> >>
> >> That's a simple consequence of SR.
> >
> >No, it's not.
>
> Yes, it is.

It's the FAILURE of SR.

> This is a simple consequence of
> the Lorentz transformations. Let A be an inertial
> frame. Let B be a second inertial frame moving
> at speed v in the +x direction, as measured in
> frame A. (Let's assume that the x-axis is oriented
> left-to-right). Let there be a rod initially at rest
> in frame A, initially of length L, oriented along
> the x-direction. The left end is initially at x=0,
> and the right end is initially at x=L.
>
> Let both ends be simultaneously
> accelerated (as measured in frame A). Let the
> acceleration be brief and powerful enough so
> that immediately afterwards (as measured in frame A),
> both ends are travelling at speed v (and so are
> at rest in frame B).
>
> Let's identify 2 events: e1 = the event at
> which the left end of the rod starts accelerating.
> e2 = the event at which the right end of the
> rod starts accelerating. Let's compute the
> coordinates of these 4 events in the two frames.
> (Assume that e1 takes place at t=0)
>
> x1 = 0
> t1 = 0
> x1' = 0
> t1' = 0
>
> x2 = L
> t2 = 0
> x2' = gamma (x2 - v t2)
> = gamma L
> t2' = gamma (t2 - v/c^2 x2)
> = - gamma vL/c^2
>
> Note: in frame B, the rod is initially travelling to the
> left at speed v. In frame B, e2 takes place *before* e1.
> So the right end of the rod comes to rest in frame B *before*
> the left end. During the time between e2 and e1, the left
> end is continuing to travel to the left, but the right end
> is *not* moving. So, as measured in frame B, the rod is
> *stretching*. (If one end of a rod is moving, and the other
> end isn't, then the rod is either stretching or compressing
> or rotating).

Yeah, I did the math before, Daryll. I specfically asked you, in that
other post, if a stationary 1 unit ruler accelerates to velocity 0.866c
(acceleration was simultaneous everywhere in stationary frame) what
will be the ruler's proper length and rulers length in stationary
frame.

The naive result, the result implied by your equations above, is that
the rulers length will be 1m in stationary frame and 2m in ruler's
frame.

THAT RESULT IS A BOGUS RESULT

THAT RESULT VIOLATES ENERGY CONSERVATION (why did the ruler break,
daryll, why did it break?)

THAT RESULT DEMONSTRATES SR'S CLEAR FAILURE TO DESCRIBE A NONINERTIAL
FRAME

I can't make it any clearer than that.


> >This doesn't happen in SR.
>
> Then please explain what does happen in SR. Use
> the Lorentz transformations to compute the times
> of the accelerations of both ends in both frames.
>
> >> Who said anything about proper lengths? Why do you think
> >> that is relevant to the issue of whether SR can be used
> >> from within a noninertial frame?
> >
> >Because SR can't decide whether noninertial frames
> >should preserve or not preserve proper lengths from
> >first principles.
>
> The length of a rod as it is accelerated depends on
> the nature of the acceleration and the nature of the
> rod. You need a physical theory describing the matter
> making up the rod to actually compute the length of
> the rod in response to stresses.
>
> However, you can use the Lorentz transformations to
> conclude the following:
>
> If the rod's proper length is constant, *then*
> the left and right ends cannot accelerate identically.

Correct.
hint: the left and right ends don't _simultaneously_ accelerate in the
stationary frame, they accelerate at different times SUCH THAT THE
PROPER LENGTH REMAINS PRESERVED.

This is trivially true from GR, but from SR, is not. Hence SR fails as
a general description of noninertial frames.

> If the left and right ends accelerate identically,
> *then* the proper length of the rod cannot remain
> constant.

Think.
hint: energy conservation


Do you realize your, Tom's, Dork's, other joker's, Ben's error yet?

What a bunch of hacks.

> --
> Daryl McCullough
> Ithaca, NY

.

Relevant Pages

  • Re: TomToms stupidity (re: was always TomToms stupidity)
    ... >The ruler instantaneously accelerates to velocity 0.866c. ... >What is the length of the ruler in A's frame? ... For example, if you accelerate ... If the proper length of the rod remains constant, ...
    (sci.physics.relativity)
  • Re: TomToms stupidity (re: was always TomToms stupidity)
    ... > You just don't understand the physical situation being discussed. ... > same acceleration MEASURED IN THE INITIAL INERTIAL FRAME. ... > That is an OUTRAGEOUS way to accelerate a rod. ...
    (sci.physics.relativity)
  • Re: Is there length contraction in SRT, uncle Ben?
    ... length of the rod, setting up measurements at their will, ... manner, each in his frame. ... and L is the measured (and at the same time the proper) length ... it doesn't matter whether the measurements ...
    (sci.physics.relativity)
  • Re: TomToms stupidity (re: was always TomToms stupidity)
    ... >(acceleration was simultaneous everywhere in stationary frame) what ... rod comes to rest *before* the other end. ... >> the left and right ends cannot accelerate identically. ... write down the formula for the prediction of SR. ...
    (sci.physics.relativity)
  • Re: TomToms stupidity (re: was always TomToms stupidity)
    ... >>(acceleration was simultaneous everywhere in stationary frame) what ... >>will be the ruler's proper length and rulers length in stationary ... > rod comes to rest *before* the other end. ... on the rod simultaneously accelerate and stop accelerating. ...
    (sci.physics.relativity)
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