Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.physics.relativity > #371462 > unrolled thread

On length contraction

Back to article view | Back to sci.physics.relativity

Contents

  On length contraction kenseto <setoken@att.net> - 2015-12-05 07:55 -0800
    Re: On length contraction Maciej Woźniak <mlwozniak@wp.pl> - 2015-12-05 18:40 +0100
    Re: On length contraction kenseto <setoken@att.net> - 2015-12-05 15:49 -0800
    Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-05 22:39 -0600
      Re: On length contraction Maciej Woźniak <mlwozniak@wp.pl> - 2015-12-06 10:28 +0100
      Re: On length contraction alsor@interia.pl - 2015-12-06 05:40 -0800
        Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-06 09:03 -0600
          Re: On length contraction alsor@interia.pl - 2015-12-09 02:37 -0800
        Re: On length contraction fuller.david@hotmail.com - 2015-12-06 08:14 -0800
          Re: On length contraction fuller.david@hotmail.com - 2015-12-06 08:27 -0800
            Re: On length contraction fuller.david@hotmail.com - 2015-12-06 10:37 -0800
      Re: On length contraction kenseto <setoken@att.net> - 2015-12-06 06:21 -0800
        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-06 08:19 -0800
          Stephane Baune tries to correct Ken Shito and, in the process, embarrasses himself "Dono," <sa_ge@comcast.net> - 2015-12-07 08:35 -0800
    Re: On length contraction Thomas Heger <ttt_heg@web.de> - 2015-12-06 08:24 +0100
      Re: On length contraction Poutnik <poutnik4nntp@gmail.com> - 2015-12-06 08:41 +0100
      Re: On length contraction kenseto <setoken@att.net> - 2015-12-06 07:06 -0800
      Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-06 09:20 -0600
        Re: On length contraction Thomas Heger <ttt_heg@web.de> - 2015-12-06 21:43 +0100
          Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 09:46 -0600
      Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-06 15:09 -0600
        Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 09:49 -0600
    Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-06 08:10 -0800
      Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 10:01 -0600
        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-07 08:28 -0800
          Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-07 10:57 -0600
            Re: On length contraction mlwozniak@wp.pl - 2015-12-07 22:58 -0800
            Re: On length contraction Thomas Heger <ttt_heg@web.de> - 2015-12-08 08:44 +0100
            Re: On length contraction kenseto <setoken@att.net> - 2015-12-08 14:33 -0800
              Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-08 17:56 -0600
              Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-10 20:07 +0000
                Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 13:13 -0800
                  Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-10 17:19 -0600
                    Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-11 02:45 +0000
                      Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 21:11 -0800
                        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-11 06:57 -0800
                          Re: On length contraction kenseto <setoken@att.net> - 2015-12-11 19:20 -0800
                        Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-11 19:55 +0000
                          Re: On length contraction Plexippus Kritikos <plexik@laertesegidio.org> - 2015-12-11 23:25 +0000
                          Re: On length contraction kenseto <setoken@att.net> - 2015-12-11 19:25 -0800
                            Re: On length contraction pnalsing@gmail.com - 2015-12-11 19:48 -0800
                              Re: On length contraction pnalsing@gmail.com - 2015-12-13 14:33 -0800
                            Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-12 17:27 +0000
                            Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-14 10:12 -0600
                    Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 21:08 -0800
                      Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-11 08:04 -0600
      Re: On length contraction kenseto <setoken@att.net> - 2015-12-08 14:26 -0800
        Re: On length contraction Plexippus Kritikos <plexik@laertesegidio.org> - 2015-12-08 22:40 +0000
          Re: On length contraction kenseto <setoken@att.net> - 2015-12-09 06:50 -0800
            Re: On length contraction alsor@interia.pl - 2015-12-09 09:06 -0800
        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-09 09:47 -0800
          Re: On length contraction Plexippus Kritikos <plexik@laertesegidio.org> - 2015-12-09 18:11 +0000
            Re: On length contraction Sam Wormley <swormley1@gmail.com> - 2015-12-09 12:32 -0600
              Re: On length contraction alsor@interia.pl - 2015-12-09 11:18 -0800
              Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 06:57 -0800
          Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 06:46 -0800
    Re: On length contraction wugi <brol@brol.be> - 2015-12-06 18:18 +0100
      Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-06 12:35 -0600
        Re: On length contraction wugi <brol@brol.be> - 2015-12-06 21:58 +0100
          Re: On length contraction wugi <brol@brol.be> - 2015-12-06 22:31 +0100
          Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 10:16 -0600
        Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 13:08 -0800
          Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 14:26 -0800
            Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 14:38 -0800
            Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 15:39 -0800
    Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-06 15:07 -0600
      Re: On length contraction benj <none@gmail.com> - 2015-12-14 02:21 -0500
        Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-14 10:44 -0600
          Re: On length contraction alsor@interia.pl - 2015-12-14 08:59 -0800
          Re: On length contraction kenseto <setoken@att.net> - 2015-12-14 09:05 -0800
            Re: On length contraction alsor@interia.pl - 2015-12-14 09:48 -0800
            Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-14 12:18 -0600
              Re: On length contraction kenseto <setoken@att.net> - 2015-12-15 05:49 -0800
                Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-15 08:21 -0600
                  Re: On length contraction mlwozniak@wp.pl - 2015-12-15 23:29 -0800
                  Re: On length contraction kenseto <setoken@att.net> - 2015-12-16 07:04 -0800
                    Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-16 09:14 -0600

Page 3 of 4 — ← Prev page 1 2 [3] 4  Next page →

#371870

On Friday, December 11, 2015 at 7:25:12 PM UTC-8, kenseto wrote:
> On Friday, December 11, 2015 at 2:55:37 PM UTC-5, Michael Moroney wrote:
> > kenseto <setoken@att.net> writes:
> > 
> > >On Thursday, December 10, 2015 at 9:45:28 PM UTC-5, Michael Moroney wrote:
> > 
> > >> Freshman physics problems?  Remember we're talking about someone who can't
> > >> even solve (-6)/(-2).  (speaking of 4th Grade!)
> > 
> > >Making up stuff.....that's why you are moron moroney.
> > 
> > So tell us, what is the answer to (-6)/(-2) and why is that the correct
> > answer?
> 
> Why would I waste my time doing a math problem for a moron???

You mean, wasting about 1/3 second? Took you longer to respond than it should have taken to just answer... could it be you don't know the answer?

[toc] | [prev] | [next] | [standalone]

#371960

On Friday, December 11, 2015 at 7:48:17 PM UTC-8, pnal...@gmail.com wrote:
> On Friday, December 11, 2015 at 7:25:12 PM UTC-8, kenseto wrote:
> > On Friday, December 11, 2015 at 2:55:37 PM UTC-5, Michael Moroney wrote:
> > > kenseto <setoken@att.net> writes:
> > > 
> > > >On Thursday, December 10, 2015 at 9:45:28 PM UTC-5, Michael Moroney wrote:
> > > 
> > > >> Freshman physics problems?  Remember we're talking about someone who can't
> > > >> even solve (-6)/(-2).  (speaking of 4th Grade!)
> > > 
> > > >Making up stuff.....that's why you are moron moroney.
> > > 
> > > So tell us, what is the answer to (-6)/(-2) and why is that the correct
> > > answer?
> > 
> > Why would I waste my time doing a math problem for a moron???
> 
> You mean, wasting about 1/3 second? Took you longer to respond than it should have taken to just answer... could it be you don't know the answer?

Perhaps I should have said (-1)/(-3) of a second...

[toc] | [prev] | [next] | [standalone]

#371903

kenseto <setoken@att.net> writes:

>> So tell us, what is the answer to (-6)/(-2) and why is that the correct
>> answer?

>Why would I waste my time doing a math problem for a moron???

Just as I predicted:

>>(Prediction: Like before, lots of evasion in response but no actual
>>answer)

In addition, you wasted more time complaining about wasting your time than
by actually giving the answer!

[toc] | [prev] | [next] | [standalone]

#371997

On 12/11/2015 9:25 PM, kenseto wrote:
> On Friday, December 11, 2015 at 2:55:37 PM UTC-5, Michael Moroney wrote:
>> kenseto <setoken@att.net> writes:
>>
>>> On Thursday, December 10, 2015 at 9:45:28 PM UTC-5, Michael Moroney wrote:
>>
>>>> Freshman physics problems?  Remember we're talking about someone who can't
>>>> even solve (-6)/(-2).  (speaking of 4th Grade!)
>>
>>> Making up stuff.....that's why you are moron moroney.
>>
>> So tell us, what is the answer to (-6)/(-2) and why is that the correct
>> answer?
>
> Why would I waste my time doing a math problem for a moron???
>

The problem, Ken, is that you believe that learning basic math skills 
and basic physics is a waste of time. You want to jump right to the 
forefront without learning the basics. Never works.

-- 
Odd Bodkin --- maker of fine toys, tools, tables

[toc] | [prev] | [next] | [standalone]

#371794

On Thursday, December 10, 2015 at 6:19:13 PM UTC-5, Odd Bodkin wrote:
> On 12/10/2015 3:13 PM, kenseto wrote:
> > On Thursday, December 10, 2015 at 3:08:00 PM UTC-5, Michael Moroney wrote:
> >> kenseto <setoken@att.net> writes:
> >>
> >>> On Monday, December 7, 2015 at 11:57:28 AM UTC-5, Odd Bodkin wrote:
> >>
> >>>> Seto has the preconception that only material things are real, and this
> >>>> gets in the way of just about everything he says. But even Seto has to
> >>>> admit that an electric field is real but it is in no way material, or
> >>>> that light is real but is in no way material. This *should* be enough to
> >>>> get him to stop saying that if it's not material then it's not real. But
> >>>> then again, Seto's on a pretty steep decline.
> >>
> >>> ROTFLOL....idiot Bodkin (aka PD) need to study 20 years more of real
> >>> physics before reaching my understanding of real physics.
> >>
> >> I suppose that if either Bodkin or PD are fairly old, they may start
> >> to suffer from a bad case of Alzheimer's, and over the next 20 years
> >> they'll degenerate to reaching your understanding of physics.
> >
> > ROTFLOL.....moron moroney
> >
> 
> Ken, I realize you're bent in the head. But really. Open up a freshman 
> book and go to, say, chapter 4 and head to the end of the chapter and 
> select ANY of the end-of-chapter problems. You will not be able to work 
> it or explain how to solve it.
> 
> Now tell me how it is that someone who can't work a single problem from 
> a freshman level physics book is 20 years ahead in understanding 
> physics. Do you think there was ever ANYONE who made an advance in 
> physics that could not work a freshman physics problem?

Yes you.

[toc] | [prev] | [next] | [standalone]

#371815

On 12/10/2015 11:08 PM, kenseto wrote:
> On Thursday, December 10, 2015 at 6:19:13 PM UTC-5, Odd Bodkin wrote:
>> On 12/10/2015 3:13 PM, kenseto wrote:
>>> On Thursday, December 10, 2015 at 3:08:00 PM UTC-5, Michael Moroney wrote:
>>>> kenseto <setoken@att.net> writes:
>>>>
>>>>> On Monday, December 7, 2015 at 11:57:28 AM UTC-5, Odd Bodkin wrote:
>>>>
>>>>>> Seto has the preconception that only material things are real, and this
>>>>>> gets in the way of just about everything he says. But even Seto has to
>>>>>> admit that an electric field is real but it is in no way material, or
>>>>>> that light is real but is in no way material. This *should* be enough to
>>>>>> get him to stop saying that if it's not material then it's not real. But
>>>>>> then again, Seto's on a pretty steep decline.
>>>>
>>>>> ROTFLOL....idiot Bodkin (aka PD) need to study 20 years more of real
>>>>> physics before reaching my understanding of real physics.
>>>>
>>>> I suppose that if either Bodkin or PD are fairly old, they may start
>>>> to suffer from a bad case of Alzheimer's, and over the next 20 years
>>>> they'll degenerate to reaching your understanding of physics.
>>>
>>> ROTFLOL.....moron moroney
>>>
>>
>> Ken, I realize you're bent in the head. But really. Open up a freshman
>> book and go to, say, chapter 4 and head to the end of the chapter and
>> select ANY of the end-of-chapter problems. You will not be able to work
>> it or explain how to solve it.
>>
>> Now tell me how it is that someone who can't work a single problem from
>> a freshman level physics book is 20 years ahead in understanding
>> physics. Do you think there was ever ANYONE who made an advance in
>> physics that could not work a freshman physics problem?
>
> Yes you.
>
>

Tell you what. You pick a freshman physics problem from a book that you 
think you can solve. Then we'll see who can solve it.

-- 
Odd Bodkin --- maker of fine toys, tools, tables

[toc] | [prev] | [next] | [standalone]

#371604

On Sunday, December 6, 2015 at 11:10:23 AM UTC-5, rotchm wrote:
> On Saturday, December 5, 2015 at 10:55:53 AM UTC-5, kenseto wrote:
> 
> 
> Hello sir... first time poster here...
> 
> > So what is length contraction in SR? 
> 
> See below...
> 
> > SRians claim that length contraction is the geometric projection 
> 
> No they dont. Stop lying. *Some* SRians *call* it that way, or describe it that way. 
> 
> "length contraction" is simply an expression used to describe the the "odd result" predicted by SR that if you *measure* the length of [a moving object] you will get a "lesser value". SR says nothing about "real" or "material". It simply says something about the *value* obtained by the measurement procedure. 

Idiot you are clueless in SR....you can't measure the physical length of a moving meter stick. You can predict its contracted lenngth. The problem is that all you SRians have no clue what is contracting because a moving meter stick will return the same length after a journey. The informed SRians came up with the idea that length contraction is the geometric projection of a moving meter stick onto the x-axis of the observer's coordinate system.


> 
> Just like if you measure the "angle height" of someone; the further they are, the lesser the angle height. Some may just *say* that the far away person is shorter. You need to understand the meaning of the words used, something you fail to comprehend.

[toc] | [prev] | [next] | [standalone]

#371607

kenseto

>> "length contraction" is simply an expression used to describe the the
>> "odd result" predicted by SR that if you *measure* the length of [a
>> moving object] you will get a "lesser value". SR says nothing about
>> "real" or "material". It simply says something about the *value*
>> obtained by the measurement procedure.
> 
> Idiot you are clueless in SR....you can't measure the physical length of
> a moving meter stick. 

This is exorbitantly correct.

> You can predict its contracted lenngth. The
> problem is that all you SRians have no clue what is contracting because
> a moving meter stick will return the same length after a journey. The
> informed SRians came up with the idea that length contraction is the
> geometric projection of a moving meter stick onto the x-axis of the
> observer's coordinate system.

Well, this gymnastics is again courageously hypothetical. Merely a 
gedanken. You can't possibly project anything, travelling at that high 
speed, on a stationary axis. To do that you need some shadows of some art, 
also considered straight and not curved. (yes, if light can curves, its 
shadow may curves as well)

[toc] | [prev] | [next] | [standalone]

#371652

On Tuesday, December 8, 2015 at 5:40:37 PM UTC-5, Plexippus Kritikos wrote:
> kenseto
> 
> >> "length contraction" is simply an expression used to describe the the
> >> "odd result" predicted by SR that if you *measure* the length of [a
> >> moving object] you will get a "lesser value". SR says nothing about
> >> "real" or "material". It simply says something about the *value*
> >> obtained by the measurement procedure.
> > 
> > Idiot you are clueless in SR....you can't measure the physical length of
> > a moving meter stick. 
> 
> This is exorbitantly correct.
> 
> > You can predict its contracted lenngth. The
> > problem is that all you SRians have no clue what is contracting because
> > a moving meter stick will return the same length after a journey. The
> > informed SRians came up with the idea that length contraction is the
> > geometric projection of a moving meter stick onto the x-axis of the
> > observer's coordinate system.
> 
> Well, this gymnastics is again courageously hypothetical. Merely a 
> gedanken. You can't possibly project anything, travelling at that high 
> speed, on a stationary axis. To do that you need some shadows of some art, 
> also considered straight and not curved. (yes, if light can curves, its 
> shadow may curves as well)
,
They use the LT to predict the contract length of a moving meter stick. They then say that the project length of a moving meter stick is 1/gamma. In addition they claim that the length of a moving is measured to be shorter by a factor of 1/gamma.

[toc] | [prev] | [next] | [standalone]

#371671

W dniu środa, 9 grudnia 2015 15:50:07 UTC+1 użytkownik kenseto napisał:

> They use the LT to predict the contract length of a moving meter stick. They then say that the project length of a moving meter stick is 1/gamma. In addition they claim that the length of a moving is measured to be shorter by a factor of 1/gamma.

LT:
x' = k(x-vt);
so, there is the contraction, of an unit of distance, already: k.

t' = t = inv.

[toc] | [prev] | [next] | [standalone]

#371679

On Tuesday, December 8, 2015 at 5:26:08 PM UTC-5, kenseto wrote:
 
> Idiot you are clueless in SR....

Idiot ken, you are clueless. 

> you can't measure the physical length of a moving meter stick. 

I never said that we can. Cant you even read? I said that *if* you measure its length, SR predicts that the value will be "Lo/g". All actual derives measurements support this and all direct exp's on TD agree with SR's predictions. It is just you who cant to basic math and is very confused about reality...

[toc] | [prev] | [next] | [standalone]

#371681

rotchm

>> you can't measure the physical length of a moving meter stick.
> 
> I never said that we can. Cant you even read? I said that *if* you
> measure its length, SR predicts that the value will be "Lo/g". All
> actual derives measurements support this and all direct exp's on TD
> agree with SR's predictions. It is just you who cant to basic math and
> is very confused about reality...

That IF is misplaced. There can't be iFs once you know a measurement or an 
observation is not physically possible. Often error done in Relativity, 
substituting "predictions" and gedankens to Measurements and Observations. 
It is a game, to make Relativity more plausible.

On the other hand, this thing was not possible in Relativity till 
yesterday. Now it is. (turning gravity into light)

Turning Gravity Into Light
https://www.youtube.com/watch?v=Jsc-pQIMxt8

[toc] | [prev] | [next] | [standalone]

#371685

   Let me illustrate time dilation AND length contraction with cosmic
   muons.

   Let ∆t_muon be an interval of proper time in the inertial frame
   of reference of a cosmic muon, say 2.2 µs.

   Let ∆t_muon' be the muon's time interval as measured by an observer
   on the surface of the earth.

   Then it follow that from the Earth Surface Perspective:

      ∆t_muon' = γ ∆t_muon
      Muon-Earth Surface Distance' = Muon-Earth Surface Distance

   And from the Muon Perspective:

      ∆t_muon' = ∆t_muon
      Muon-Earth Surface Distance' = Muon-Earth Surface Distance / γ

   Where v is the relative velocity between muon and Earth Surface and

      γ = 1/√(1-v^2/c^2)



-- 

sci.physics is an unmoderated newsgroup dedicated
to the discussion of physics, news from the physics
community, and physics-related social issues.

[toc] | [prev] | [next] | [standalone]

#371694

W dniu środa, 9 grudnia 2015 19:33:00 UTC+1 użytkownik Sam Wormley napisał:
> Let me illustrate time dilation AND length contraction with cosmic
>    muons.
> 
>    Let ∆t_muon be an interval of proper time in the inertial frame
>    of reference of a cosmic muon, say 2.2 µs.
> 
>    Let ∆t_muon' be the muon's time interval as measured by an observer
>    on the surface of the earth.
> 
>    Then it follow that from the Earth Surface Perspective:
> 
>       ∆t_muon' = γ ∆t_muon
>       Muon-Earth Surface Distance' = Muon-Earth Surface Distance
> 
>    And from the Muon Perspective:
> 
>       ∆t_muon' = ∆t_muon
>       Muon-Earth Surface Distance' = Muon-Earth Surface Distance / γ
> 
>    Where v is the relative velocity between muon and Earth Surface and
> 
>       γ = 1/√(1-v^2/c^2)

That means just: t = inv.

[toc] | [prev] | [next] | [standalone]

#371749

On Wednesday, December 9, 2015 at 1:33:00 PM UTC-5, Sam Wormley wrote:
> Let me illustrate time dilation AND length contraction with cosmic
>    muons.
> 
>    Let ∆t_muon be an interval of proper time in the inertial frame
>    of reference of a cosmic muon, say 2.2 µs.
 
2.2 us on the muon clock  is worth gamma*2.2 us on the earth clock.
 
>    Let ∆t_muon' be the muon's time interval as measured by an observer
>    on the surface of the earth.
> 
>    Then it follow that from the Earth Surface Perspective:
> clock.
>       ∆t_muon' = γ ∆t_muon

Yes one second on the muon clock is worth gamma*seconds on the earth 

>       Muon-Earth Surface Distance' = Muon-Earth Surface Distance
> 
>    And from the Muon Perspective:
> 
>       ∆t_muon' = ∆t_muon
>       Muon-Earth Surface Distance' = Muon-Earth Surface Distance / γ

That's because the decay time for a moving muon is gamma*2.2 us that's why it was able to travel a much larger distance before decay.

> 
>    Where v is the relative velocity between muon and Earth Surface and
> 
>       γ = 1/√(1-v^2/c^2)
> 
> 
> 
> -- 
> 
> sci.physics is an unmoderated newsgroup dedicated
> to the discussion of physics, news from the physics
> community, and physics-related social issues.

[toc] | [prev] | [next] | [standalone]

#371748

On Wednesday, December 9, 2015 at 12:47:15 PM UTC-5, rotchm wrote:
> On Tuesday, December 8, 2015 at 5:26:08 PM UTC-5, kenseto wrote:
>  
> > Idiot you are clueless in SR....
> 
> Idiot ken, you are clueless. 
> 
> > you can't measure the physical length of a moving meter stick. 
> 
> I never said that we can. Cant you even read? I said that *if* you measure its length, SR predicts that the value will be "Lo/g". All actual derives measurements support this and all direct exp's on TD agree with SR's predictions. It is just you who cant to basic math and is very confused about reality...
 
Idiot.....how is your "IF you measure" procedure better than Tom Roberts' geometric projection procedure and my "light-path length" contraction  prediction? All three procedures give the same prediction. However my procedure does not give rise to paradoxes.

[toc] | [prev] | [next] | [standalone]

#371497

kenseto schreef op 5/12/2015 om 16:55:
> On length contraction according to SR:
> 1. A meter stick M is moving wrt observers A, B and C.
>
> 2. A predicts (SRians claim "Measures") the contracted length of M is 1/gamma_am.
>
> 3. B predicts (SRians claim "Measures") the contracted length of M is 1/gamma_bm.
>
> 4. C predicts (SRians claim "Measures") the contracted length of M is 1/gamma_cm.
>
> It is obvious that M cannot have different contracted material lengths as
>predicted by the different observers.

Says who? It can and does have them very well.

>That means that length contraction in SR is not material (not real).

Yes it is (real material).

 >So what is length contraction in SR? SRians
>claim that length contraction is the geometric projection of the meter stick
>onto the x-axis of observer's coordinate system.

It is that too. Besides real and material.

What appears to bother most "SRian-bashers", is the seeming 
incompatibility worded by stating that "if (1) A < B, then (2) B < A 
can't be".
This stems from the lack of realisation that different events are to be 
considered in establishing (1) and (2). For your case for instance: in 
defining and comparing lengths of M in A, and again of A in M. (And of 
B; and C...).
Once one does realise so, it is easily understood that the studied 
"moving object" itself (its set of world lines) is not affected nor 
changed by this or that measurement. It is only the sets of "events to 
be chosen" for this or that measurement that are different.
And their differences turn out to be nicely mutual, so yes
A=B/gamma and B'=A'/gamma
are not contradictary but obvious.
http://home.pi.be/~pin12499/MySRT/LorentzObjects.PNG

Now, if for its measurement a moving object is not affected, "identical" 
objects moving wrt each other *are* affected in that they could not 
"instantly become each other". During the acceleration process that 
makes one object approach the other's frame, a physical change has to 
happen, which pertains to the physical reality of length contraction 
(and time dilation).
Some classical paradoxes use (or abuse:) this feature.

-- 
guido
http://home.pi.be/~pin12499/paratwin.htm

[toc] | [prev] | [next] | [standalone]

#371498

On 12/6/15 12/6/15   11:18 AM, wugi wrote:
> [...]
> And their differences turn out to be nicely mutual, so yes
> A=B/gamma and B'=A'/gamma
> are not contradictary but obvious.
> http://home.pi.be/~pin12499/MySRT/LorentzObjects.PNG

Yes, this is correct.


> Now, if for its measurement a moving object is not affected, "identical" objects
> moving wrt each other *are* affected in that they could not "instantly become
> each other".

No. Though you got it right earlier, here you are in error. Simply moving an 
object does not "affect" it (the object itself), though it can affect its 
relationships to other objects (such as clocks and rulers).

If I take two ladders and rotate one, could they "instantly become each other"? 
-- well I don't know what meaning you attach to that rather curious phrase (how 
could ANY pair of objects "instantly become each other"????? -- we cannot 
perform such magic in the world we inhabit). So I'll assume you mean that they 
are not congruent to each other (e.g. as they pass each other moving along an 
East-West line, at some instant their Eastern ends are adjacent but their 
Western ends are not, as seen in either object's rest frame).

The underlying point in SR is that relatively-moving objects are NOT parallel to 
each other. But the rotation is in a space-time plane, which most people are not 
familiar with. But like the ladders, rotations do NOT affect the object itself, 
just its relationship to other objects (e.g. its relationship to rulers in some 
other frame that are used to measure its length as seen by that frame).


> During the acceleration process that makes one object approach the
> other's frame, a physical change has to happen, which pertains to the physical
> reality of length contraction (and time dilation).

This is also wrong. In SR, no "physical change" occurs due to acceleration, such 
that it persists after the acceleration stops. BTW this also appears to be true 
to high accuracy in the world we inhabit (unless the acceleration is so large 
that it breaks the object, making it no longer the same object).

In SR this OUGHT to be obvious, because the Principle of Relativity directly 
implies that the laws of physics are the same in any inertial frame. So for a 
given object, the intra- and inter-atomic forces, relationships, and distances 
are the same regardless of which inertial frame the object happens to be at rest 
in. That is, when measured in its rest frame, the length of an object and the 
tick rate of a clock are ALWAYS equal to their usual values.

So simply accelerating on object to be at rest in some other inertial frame does 
NOT "change" the object itself.


> Some classical paradoxes use (or abuse:) this feature.

I don't know what you mean here, since your "feature" is wrong.

	Yes, popular writings on relativity often use the phrase "moving
	clocks run slow". This is WRONG, and anyone who understands the
	basics of SR can easily see why -- if the clock "runs slow" that
	implies that the laws of physics that govern its ticking are
	DIFFERENT in the moving frame, but the PoR says those laws are
	the same in every frame. What is "slow" is MEASUREMENTS of the
	clock from frames in which it is moving, not the clock itself
	(but that phrase says that the clock itself is "slow").


Tom Roberts

[toc] | [prev] | [next] | [standalone]

#371503

Tom Roberts schreef op 6/12/2015 om 19:35:
> On 12/6/15 12/6/15   11:18 AM, wugi wrote:
>> [...]
>> And their differences turn out to be nicely mutual, so yes
>> A=B/gamma and B'=A'/gamma
>> are not contradictary but obvious.
>> http://home.pi.be/~pin12499/MySRT/LorentzObjects.PNG
>
> Yes, this is correct.
>
>
>> Now, if for its measurement a moving object is not affected,
>> "identical" objects
>> moving wrt each other *are* affected in that they could not "instantly
>> become
>> each other".
>
> No. Though you got it right earlier, here you are in error. Simply
> moving an object does not "affect" it (the object itself), though it can
> affect its relationships to other objects (such as clocks and rulers).

What I meant is that moving objects are affected, not when in inertial 
movement but when switching between such.

> If I take two ladders and rotate one, could they "instantly become each
> other"? -- well I don't know what meaning you attach to that rather
> curious phrase (how could ANY pair of objects "instantly become each
> other"????? -- we cannot perform such magic in the world we inhabit). So
> I'll assume you mean that they are not congruent to each other (e.g. as
> they pass each other moving along an East-West line, at some instant
> their Eastern ends are adjacent but their Western ends are not, as seen
> in either object's rest frame).

That's one of the ways I meant, sure...

> The underlying point in SR is that relatively-moving objects are NOT
> parallel to each other. But the rotation is in a space-time plane, which
> most people are not familiar with. But like the ladders, rotations do
> NOT affect the object itself, just its relationship to other objects
> (e.g. its relationship to rulers in some other frame that are used to
> measure its length as seen by that frame).

Well, I see it less as abstract mathematical rotation and more as "real 
gedanken-"physical movement, ...

>> During the acceleration process that makes one object approach the
>> other's frame, a physical change has to happen, which pertains to the
>> physical
>> reality of length contraction (and time dilation).
>
> This is also wrong. In SR, no "physical change" occurs due to
> acceleration, such that it persists after the acceleration stops. BTW
> this also appears to be true to high accuracy in the world we inhabit
> (unless the acceleration is so large that it breaks the object, making
> it no longer the same object).

... and IMO some 'rearrangement' is really going on during relativistic 
acceleration.
When, as you suggested hereabove, their Eastern ends are adjacent then,
1) the Western end, contracted, of the moving object would have to be 
'forced' to its non-contracted non-moving counterpart, (simultaneity at 
rest system) or
2) the Western end, contracted, of the non-moving object would have to 
be forced to its non-contracted, moving counterpart (simultaneity of 
moving system).
That would be forcing things. A "normal" acceleration would try to pass 
along a continous set of instantaneous inertial systems (Born rigid 
acceleration), but other accelerations generating internal forces are 
easily imaginable.

> In SR this OUGHT to be obvious, because the Principle of Relativity
> directly implies that the laws of physics are the same in any inertial
> frame. So for a given object, the intra- and inter-atomic forces,
> relationships, and distances are the same regardless of which inertial
> frame the object happens to be at rest in. That is, when measured in its
> rest frame, the length of an object and the tick rate of a clock are
> ALWAYS equal to their usual values.
>
> So simply accelerating on object to be at rest in some other inertial
> frame does NOT "change" the object itself.

Acceleration description is mostly limited to local, point-like cases. 
But I'm considering acceleration (gradients) "throughout large 
relativistic rigid objects", which of course is multiple gedanken, but 
anyway.

>> Some classical paradoxes use (or abuse:) this feature.
>
> I don't know what you mean here, since your "feature" is wrong.

I think not;-)
I was thinking TP (frequent argument: time dilation, so A keeps younger 
than B, and B keeps younger than A: paradox!);
and recently the rivet paradox was around here (in one system the bug is 
hit first, in the other the wall, so: impossible!??)
http://hyperphysics.phy-astr.gsu.edu/Hbase/Relativ/bugrivet.html
Some approaches for an answer:
http://math.ucr.edu/~jdp/Relativity/Bug_Rivet.html
http://brianclegg.blogspot.fr/2011_11_01_archive.html
https://www.physicsforums.com/threads/what-is-the-resolution-of-the-the-bug-rivet-paradox-paradox-in-special-relativity.57063/
But I decided to draw my own solution. See
http://home.scarlet.be/~pin12499/draaft/RivetParadox1.jpg
Standpoint of opening. The rivet head is stopped in O, then its other 
end in A. The light signals propagating both events meet
in B.
Region OB generates stretch, and BA pressure. From there the ratio OB 
vs. BA is restored, and stresses vanish: "inertial state reached".

http://home.scarlet.be/~pin12499/draaft/RivetParadox2.jpg
Standpoint of rivet. The rivet end is stopped first, in A; then its head 
in O. Both propagation signals meet, again, in B. Same conclusions further.

So, no paradox. Much ado yet, only because the general formulations 
exaggerate the differences and suggest causal links that are not there.

-- 
guido

[toc] | [prev] | [next] | [standalone]

#371508

wugi schreef op 6/12/2015 om 21:58:
> Tom Roberts schreef op 6/12/2015 om 19:35:

>>> Some classical paradoxes use (or abuse:) this feature.
>>
>> I don't know what you mean here, since your "feature" is wrong.
>
> I think not;-)
> I was thinking TP (frequent argument: time dilation, so A keeps younger
> than B, and B keeps younger than A: paradox!);
> and recently the rivet paradox was around here (in one system the bug is
> hit first, in the other the wall, so: impossible!??)
> (...)

And of course the pole-barn paradox
("what if pole-in-barn were ""instantly frosen"" in their positions, 
whether it be along the pole system, or along the barn system?")

-- 
guido

[toc] | [prev] | [next] | [standalone]

Page 3 of 4 — ← Prev page 1 2 [3] 4  Next page →

Back to top | Article view | sci.physics.relativity

csiph-web