Is Length Contraction in SR physical??
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From: NoEinstein on 8 Feb 2010 15:28 On Feb 2, 10:52 am, PD <thedraperfam...(a)gmail.com> wrote: > Dear Readers: PD, the Parasite Dunce, is incapable of learning anything. He used to be a teacher (big deal). Yet, he can't accept that the kinetic energy equationwhich inputs velocity UNIFORMLYcan't have a resulting KE increasing exponentially, or KE = 1/2 mv^2, according to Coriolis's errant formula. Einstein based his SR on the latter KE equation, but he dropped the 1/2, for some unexplained reason. Both the equations of Coriolis and Einstein, in his SR, violate the Law of the Conservation of energy, by GETTING OUT more energy than is being put in by velocity. PD considers that distance traveled is a 'free' energy component of velocity. But find KE wherever he may, both Coriolis and Einstein still violate the Law of the Conservation of Energy. If the Coriolis equation was correct, then WHERE does the exponentially increasing energy come from? NoEinstein > > On Feb 2, 9:40 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > On 1 Feb, 20:52, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Feb 1, 2:49 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > So does that mean that length contraction is not physical? > > > > No, it does not mean that. > > > Why do you think that "observer dependent" means "not physical"? > > > Lots of physical properties are observer dependent. > > > Because for anyone who believes in material reality, physical > > properties should not be "observer dependent", > > Then I would ask the following questions of you. > Is velocity a physical property? It is *clearly* observer-dependent. > Having answered that, is kinetic energy a physical property, given > that (at least at low speeds) the kinetic energy is proportional to > the square of the velocity, and so is also clearly observer-dependent. > Having answered that, is the law of conservation of energy, which > includes kinetic energy as one of the contributions to the conserved > sum, a law about physical properties? If not, then what is it a law > about? > > > and if physical > > properties do indeed seem to change depending on how they are > > observed, then there should be some coherent explanation for it rather > > than just a statement that things are "observer dependent", which in > > most people's minds rather leaves the glaring question "why". > > I think there may just be a clash regarding an unfounded expectation > that physical properties "should" be observer-independent. Why would > this be an expectation? > The reality is that physics is littered with physical properties, > about which there are many laws that seem to hold remarkably well. > Some of those properties are observer-dependent, and some are observer- > independent. There is no rationale required for "why" they are not all > one way or the other, any more than there has to be a reason cited for > "why" all animals are not mammals. > > PD
From: kenseto on 8 Feb 2010 15:58 On Feb 8, 3:25 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 7, 8:39 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > When Ken started asking these questions 15 years ago, they were > > > reasonable questions. When after a couple of years it was clear he was > > > not listening to the answers given to his questions, the tone of the > > > responses became a little different. > > > Why should I listen to what you said when you did made sense.?? > > Ken, it isn't wise to stop listening to people if you do not > understand what they are saying. It would be important in that case to > say, "I don't understand what you are saying. Can you explain it > differently so I can understand it?" I don't listen to you because you keep on making contradictory claims. For example the pole is physically contracted to fit the barn and at the same time the pole does not fit into the barn because it is not physically contracted.
From: kenseto on 8 Feb 2010 16:09 On Feb 8, 3:09 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 8, 12:38 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > > > On Feb 8, 11:42 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Feb 7, 7:34 am, kenseto <kens...(a)erinet.com> wrote: > > > > > On Feb 6, 10:57 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Feb 6, 9:02 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 6 Feb, 17:16, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > On Feb 5, 8:14 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > > On 5 Feb, 16:00, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > > On Feb 4, 9:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > > > > On 5 Feb, 02:48, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > > > > > > > > > wrote: > > > > > > > > > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > > > > > > > > > >news:3979bca1-a35e-4399-bc71-75d2fc680757(a)21g2000yqj.googlegroups.com... > > > > > > > > > > > On 5 Feb, 01:12, artful <artful...(a)hotmail.com> wrote: > > > > > > > > > > > > > On Feb 5, 11:49 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > > > > > > On Feb 4, 6:04 pm, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > > > > > > > > > On Feb 4, 5:59 pm, "kens...(a)erinet.com" <kens....(a)erinet.com> wrote: > > > > > > > > > > > > > > > > It it does violate the PoR. You made the contradcictory claims that > > > > > > > > > > > > > > > the pole can fit into the barn physically (materially) an at the > > > > > > > > > > > > > > > same > > > > > > > > > > > > > > > time you claim that the pole cannot fit into the barn physically > > > > > > > > > > > > > > > (materially)......that a violation of the PoR.. > > > > > > > > > > > > > > > No. The doors are not closed simultaneously in the pole's frame, nor > > > > > > > > > > > > > > are the two ends of the pole simultaneously in the barn in the pole's > > > > > > > > > > > > > > reference frame. In the barn's frame, the two ends of the pole are in > > > > > > > > > > > > > > the barn simultaneously and the doors shut simultaneously. In the > > > > > > > > > > > > > > pole's frame, the two ends of the pole are in the barn at different > > > > > > > > > > > > > > times and the doors shut at different times. > > > > > > > > > > > > > > Sigh..You are making the contradictory claims: > > > > > > > > > > > > > 1. The pole can fit into the barn with both doors close > > > > > > > > > > > > > simultaneously. > > > > > > > > > > > > > In the frame of the barn > > > > > > > > > > > > > > 2. The pole cannot fit into the barn with both doors close > > > > > > > > > > > > > simultaneously. > > > > > > > > > > > > > In the frame of the pole > > > > > > > > > > > > > Two different meanings for 'simultaneously'. So they are not > > > > > > > > > > > > contradictory > > > > > > > > > > > > > You really are not very good at thinking or arguing logically. > > > > > > > > > > > > He seems perfectly reasonable to me. > > > > > > > > > > > > He's saying that, if one stands in the middle of the barn equidistant > > > > > > > > > > > from the doors on each side, and one closes the doors simultaneously > > > > > > > > > > > (i.e. what I would call "absolutely simultaneously", but which for > > > > > > > > > > > conveience we'll say "simultaneous according to an observer standing > > > > > > > > > > > equidistant from each door), then is it possible that both doors can > > > > > > > > > > > appear closed while the ladder is observed to be inside the barn. > > > > > > > > > > > > It's a simple question, and the answer is "no!". > > > > > > > > > > > > ______________________________ > > > > > > > > > > > Its a simple question, and the answer is "yes". It is quite easy to devise > > > > > > > > > > > an inertial frame in which the doors both appear closed and the ladder is > > > > > > > > > > > fully contained in the barn. > > > > > > > > > > > The question wasn't whether "an inertial frame can be devised...". > > > > > > > > > > Even I can think of situations where it would *appear* that the ladder > > > > > > > > > > was inside and both doors closed. The question is whether this is an > > > > > > > > > > artefact of observation, or whether the ladder is actually inside with > > > > > > > > > > both doors closed. The answer remains "no, the ladder does not fit > > > > > > > > > > inside with both doors closed". > > > > > > > > > > There is a simple test. > > > > > > > > > We can determine whether the doors closed simultaneously. We do this > > > > > > > > > using the test of simultaneity I indicated to you above: > > > > > > > > > 1. Have the door-closings generate signals that travel at identical > > > > > > > > > speeds from either event. > > > > > > > > > 2. Have a detector positioned at equal distance from the barn doors. > > > > > > > > > 3. If the detector receives the signals from the barn door-closings at > > > > > > > > > the same time, then the two doors closed simultaneously unambiguously. > > > > > > > > > You and I have agreed on this procedure. > > > > > > > > > If the detector is stationary, then yes we agree that this determines > > > > > > > > simultaneity. > > > > > > > > > > Secondly, we can determine whether any part of the pole was outside > > > > > > > > > the barn when those doors were closed by looking for the marks the > > > > > > > > > ends of the pole would have made on the door. In the absence of those > > > > > > > > > marks, we can safely conclude that the entire pole was inside the barn > > > > > > > > > at the time the doors were closed. > > > > > > > > > Agreed. I would expect this test is definitive, were it possible to > > > > > > > > carry out. > > > > > > > > And this has been tested in equivalent experiment. Documented.. > > > > > > > Has it really? Which experiment was that, because my sources say that > > > > > > length contraction has *never* been experimentally observed. > > > > > > I already told you the answer to that. Please look again. > > > > > > > > Seto does not read experimental papers, because he finds them > > > > > > > confusing. So instead he believes what makes sense to him, rather than > > > > > > > letting experimental results tell him something different. > > > > > > > You have to concede at least the possibility Paul that the reason Ken > > > > > > finds them confusing, and so do I, is because *we* can see that they > > > > > > rest on certain assumptions. That is, assumptions that you've > > > > > > internalised, and assumptions which me and Ken reject. > > > > > > In Seto's case, it has more to do with thinking that SR says something > > > > > it does not. I haven't yet figured out whether you are in the same > > > > > boat. > > > > > The only assumptions I make are those that have testable consequences. > > > > > Which ones of those do you think I have that you reject? > > > > > So are you saying that SR doesn't say that the pole can be completely > > > > inside the barn with both doors close simultaneously? > > > > SR *certainly* does not say that this statement holds true in both > > > barn frame and pole frame. > > > If you thought it did, then you never understood what SR says. > > > I didn't say that that statement hold true in both barn and pole > > frame. > > Yes, you did. Two days ago you said just this: "The pole observer have > to agree with the barn observer that the pole > is completely inside the barn with both door close simultnaeously." So??? What I said here is that I disagree with the SR assertions that the pole is physically contracted in one frame and not physically contracted in another frame. Since there is only one pole it is either contracted or not contracted....but not both. A physically contracted pole cannot suddenly not physically contracted. That's why informed physicists such as Tom Roberts reject the idea of physical length contraction.... instead he said that the length contraction idea in SR is a geometric projection of the pole unto the barn frame. Ken Seto > > You said they have to agree. They do not. That does not make a > contradiction. > > > > > I said that SR claim that the pole is physically contracted so > > that it can fit into the barn and that SR also made the contradictory > > assertion that the same pole is not physically contracted so that it > > is not able to fit into the barn. > > > > > I ask this > > > > question because that's what I think SR says. > > > > You are wrong about that.- Hide quoted text - > > > > - Show quoted text -- Hide quoted text - > > - Show quoted text -- Hide quoted text - > > - Show quoted text -
From: PD on 8 Feb 2010 16:10 On Feb 7, 11:19 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 8 Feb, 03:16, mpalenik <markpale...(a)gmail.com> wrote: > > > On Feb 7, 9:59 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > 3 dimensional geometry does need a physical explanation, and it's very > > > easy to provide one that appeals to our most obvious intuitions. > > > I just wanted to say "it appeals to our most obvious intuitions" is > > not a physical reason. > > Yes it is, because what we observe *is* physical reality. This statement carries no small dose of irony. Recall earlier that when we were discussing observed velocities and kinetic energies and momenta, which are frame-dependent, you declared off the top of your head that reality cannot be frame-dependent, and therefore what we observe is NOT reality.
From: mpalenik on 8 Feb 2010 19:40
On Feb 8, 3:21 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 8, 3:57 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > Indeed, I have no information about how the decay products are > > measured in these accelerators nor access to the raw data set, and I'm > > not willing to take the word of scientific authority in which I have > > utterly no faith, particularly because so many supposed experts appear > > to have no insight whatsoever into the physical nature of their > > mathematical models, and even more shockingly the request for a > > physical explanation often produces the reply "what do you mean by > > physical", as though it needed to be defined! > > Well, here we run into the small conundrum: > S: "I don't see why I should believe this theory without a physical > model that makes sense to me." > P: "Well, you see, physicists choose which model to believe based on > which of the models matches the largest set of experimental data." > S: "But I don't believe the experimental data either, because I do not > trust that they haven't been skewed by physicists." > P: "What would it take for you to believe the experimental data?" > S: "It would require physicists to explain the data with a model that > makes sense to me." > > Self-fulfilling prophecy, you see. What's really funny is that he had already decided there was a systematic error in all the experiments *before* reviewing any of the experiments. Also funny is that he seems to think you can have a theory that "explains" SR while giving different numerical predictions than SR (such as the prediction of length contraction). One has to wonder in what what the two descriptions are equivalent if they predict different things. |