Re: There is no physical length contraction

On Jul 15, 8:33 am, "Whoever" <no...@xxxxxxxxxxx> wrote:
"Uncle Ben" <b...@xxxxxxxxxxx> wrote in message

news:e3e70f24-ac59-4cf6-9886-2af0788a83f0@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx





On Jul 15, 7:58 am, "Whoever" <no...@xxxxxxxxxxx> wrote:
"Uncle Ben" <b...@xxxxxxxxxxx> wrote in message

news:8ea7b297-4ba1-4302-9923-04f6c3368a90@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

On Jul 15, 2:06 am, "Whoever" <no...@xxxxxxxxxxx> wrote:
"Uncle Ben" <b...@xxxxxxxxxxx> wrote in message

news:8190fb0e-a55e-4117-8093-01c3a066328c@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

On Jul 14, 6:50 pm, shuba <tim.sh...@xxxxxxxxxxxxx> wrote:
Uncle Ben wrote:
Maybe I am in the minority of the "SRians" here, but the breaking
of
a
string seems awfully "physical to me, projection or not.
Cf:"Bell's
Spaceship Paradox", in Wikipedia.

Can you point to *any* inertial frame where the string isn't
measured to break to support your bizarre idea that Lorentz
contraction has something to do with an analysis of the
experiment? Do you know what a coordinate transformation is? Or
do you simply deny that the Lorentz contraction is based on a
coordinate transformation?

Of course a breaking string is physical. This doesn't support
your tired strawman about Lorentz contractions.

         ---Tim Shuba---

Tim, we have been over this before.  I respect your point of view,
and
I wouldn't dream of trying to persuade you otherwise.

But I have a point of view also.  The Principle of Relativity
entitles
me to analyze physical phenomena from any inertial frame I choose..
I
choose the launch frame.

Fine

In that frame the length of the string remains constant.

No .. the string length in the launch frame does not stay constant.
The
string is moving in the launch frame, so is length contracted in that
frame.
In the launch frame it is the distance between corresponding points on
the
spaceships that is constant.

In the (non-inertial) frame of reference of either space ship (or the
string), the distance between corresponding point on the spaceships
increases.

In either case, the string has to stretch to stay connected to the
ships,
and so will eventually break.

The only
thing that later changes from the launch conditions is the speed of
the ships w.r.t. the launch frame.  Since we agree that the string
breaks, I point to that change as the only reasonable cause.

Arguments don't age if they are sound.

They need to BE sounds first  It sounds like you are mistaken on your
explanation here.- Hide quoted text -

- Show quoted text -

The argument is as sound as the principle of the homogeneity of space.

Here is the argument that in the launch frame the distance between the
ships -- and thus the length of the string -- is constant:

But the string will be length contracted.  The ships will try to stretch
the
string to remain at that length

In the launch frame, the motors of the two spaceships fire at the same
time.  The ships are identical. The only difference between the ships
is their initial position.

Yeup

Therefore the distance travelled by each ship in a given time (in the
launch frame) is the same.  Therefore the initial distance between the
ships does not change (w.r.t. the launch frame).

Yeup

Your criticism?

You didn't take into account the length contraction of the moving string-
Hide quoted text -

- Show quoted text -

With respect to the launch frame:

Yes

The string is tied to the ships.  If the ships remain separated by a
fixed distance, the string cannot contract. That's why it breaks.

So you didn't read what I said when I said the same thing ...





No .. the string length in the launch frame does not stay constant.
The
string is moving in the launch frame, so is length contracted in that
frame.
In the launch frame it is the distance between corresponding points on
the
spaceships that is constant.

In the (non-inertial) frame of reference of either space ship (or the
string), the distance between corresponding point on the spaceships
increases.

In either case, the string has to stretch to stay connected to the
ships,
and so will eventually break.
(It is presumed in this problem that the string is too weak to affect
the motion of the spaceships.)

Yes .. I am assuming that.- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

I'm sorry if I missed something. What I saw in your posts was a
denial of my claim that the string does not contract. You said, I
understood, that the string does contract in the launch frame, pre-
break.

Perhaps you meant that the string "tries to contract," to
anthropomorphize it. To me, "contract" means to change to a shorter
length. It does not mean "suffers an increase of stress."

Is that our difference?

Uncle Ben
.

Relevant Pages

  • Re: There is no physical length contraction
    ... >>>> In the launch frame it is the distance between corresponding points ... >> But the string will be length contracted. ... The ships are identical. ... denial of my claim that the string does not contract. ...
    (sci.physics.relativity)
  • Re: There is no physical length contraction
    ... Of course a breaking string is physical. ... the string length in the launch frame does not stay constant. ... In the frame of reference of either space ship, the distance between corresponding point on the spaceships increases. ...
    (sci.physics.relativity)
  • Re: Curvature
    ... description of the phenomenon w.r.t. the launch frame is that the ... string were not anchored to the trailing ship, ... contract as measured in a comoving inertial frame. ...
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  • Re: There is no physical length contraction
    ... string seems awfully "physical to me, ... contraction has something to do with an analysis of the ... choose the launch frame. ... the ships w.r.t. the launch frame. ...
    (sci.physics.relativity)
  • Re: There is no physical length contraction
    ... string seems awfully "physical to me, ... contraction has something to do with an analysis of the ... choose the launch frame. ... the ships w.r.t. the launch frame. ...
    (sci.physics.relativity)