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The victorious truther

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    Relativistic physics

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  1. There is no centrifugal force when seen from your inertial frame of reference.
  2. At some point the whole thing is at rest then at a later time it's moving at a constant linear and angular velocity with respect to its center of mass. Thusly, there wasn't actually any conservation of angular momentum or energy because work was done (in this case both linear as well as rotational work). Energy was not in fact conserved if this bolt went from not moving to moving. If you are truly to do this correctly you CANNOT be ignorant to what frame of reference you are in whether inertial or in the rotating frame of reference. Further, fully analyze it from the inertial frame of reference then move into the non-inertial one with mathematics to back up your conclusions.
  3. If it doesn't work when seen from an inertial frame of reference then it doesn't work at all. The only force that can be utilized is the one that is actually accelerating you. Fictitious force only arise and are present in non-inertial frames of reference because mathematically we attempt to treat an accelerating frame of reference as if it actually is at rest so we have to make up other forces to give rise to the phenomenon we observe while remaining at rest in that non-inertial frame of reference. Those forces which do not disappear after we switch frames of reference from say non-inertial to inertial (centripetal force for example) are the only real forces that you can do anything with.
  4. If you make a spacetime diagram of this situation in which one twin remained inertial while the other had a device to measure that they flipped frames of reference (remember it's relativity of inertial frames of reference not relativity of NON-INERTIAL frames of reference) then with a instantaneous turn around the non-inertial twin would notice the other twin actually jump ahead in time in a way the other twin (inertial one) would not see. If you plot the diagram you'll notice the time loss as a missing triangular section if I recall. No, both WORLD LINES cannot be treated entirely as the same as the moving twin CHANGES frames of reference half way through his journey (his proper time). So it isn't symmetric just as if a car drives away and comes back we know it was the car that accelerated (changed inertial frames of reference) as it was not the person given they both had accelerometers. If they both remained inertial then they would never meet back up again and if they were both non-inertial then their accelerometers would have noticed the inclusion of some force fictitiously into each of their respective frames of reference but the person on the ground never noticed such inertial forces arise so the only conclusion is that the car was moving, ergo it WASN'T symmetric. Why is this so hard to understand when you literally can go into a parking lot and forget about special relativity to then show this to be the case. Remember that special relativity has to simplify down to classical physics in the low speed limit. Also, acceleration is not relative in the sense that velocity is or inertial frames of reference are just as in CLASSICAL PHYSICS or in GALILEAN SPACETIME. In special relativity (as in classical physics) it isn't relative whether you are ACCELERATING or are ROTATING. We can disagree the magnitude of said quantities but whether you are or are not accelerating is not frame dependent but can rather frame independent. @michel123456 Do you understand that the postulates of special relativity are: 1. All inertial frames of reference are to be treated as equivalent in that the laws of physics behave the same in any inertial frame of reference. 2. The speed of light as measured from any arbitrary inertial frame of reference in free space is constant. This would mean that if you had a ANY non-inertial motion then by definition we could detect it and know that we are in a non-inertial reference frame because these postulates wouldn't apply. Further, this would also mean the situation of one non-inertial observer compared to an inertial one (the twin paradox) would mean by these postulates that their world lines COULD NOT be treated symmetrically or in other terms equivalently as if the non-inertial reference was inertial. AGAIN, the postulates are not, \( 1^{*} \). All frames of reference have the laws of physics behave the same within them. \( 2^{*} \). The speed of light as measured from any frame of reference in free space is constant. You seem to be under the delusion that the starred ones are what define special relativity when in relativity it's the un-starred ones.
  5. I must supremely apologize then. I must have missed some important context involved when I abruptly popped in here. Stated differently there is no relativity principle for non-inertial frames of reference in classical or relativistic physics.
  6. A theory such as special relativity or general relativity can be a successful well understood mathematical/theoretical and applied theory of how the world works. Yet we could still disagree on philosophical interpretations of the relationship of our naive realism and previous theories with their accompanying previous ontologies to this specific theory (as well as fully interpreting the theory itself). Take the discussion of proper mass and relativistic mass and ask the legitimate question of whether one/both/neither of these newer concepts in special relativity would match up intuitively/ontologically (philosophically) to the classical physics concept of inertia (mass). Is relativistic mass the relativistic counterpart to inertia or is this a false comparison? This is a legitimate question but it doesn't really come to much difficulty when it comes to actually applying said theory if you had a case to make that we applied it, expected a certain result but got the wrong one, but under a different interpretation the experimental results could be construed to be correct then i'd agree there is something contentious. . . i'll await for you to actually propose this. In the history and philosophy of physics the discussion of what forces are as well as whether we should even accept action-at-a-distance ones wasn't settled with Newtons Principia but this philosophical side discussion didn't stop us from applying successfully the mathematical results there in for generations. You just said your biased. . . Which is technically what the GALILEAN transformation already did in CLASSICAL physics but I do not see you screaming at the top of lungs about that and how it must be a perspective thing. Classical physics did the same thing of relating certain quantities in one frame of reference to that of another but they were no less real with respect to those frames of reference. Be careful with your language here. . . novice. . . when you say STOP it's implied you mean non-inertially accelerate or change reference frames so that they entered the specific one in question. Obviously if we go to classical physics in which a person who was moving with respect to our frame of reference then suddenly de-accelerate to enter our frame of reference. . . they aren't moving any more. . . cause they stopped with respect to our frame of reference. . . so if you ask whether the non-moving observer is moving then clearly no. . . because they aren't moving. To be length contracted or appear as such from other frames of reference the object in question would have to be moving. Velocity is a real effect. . . but it's frame dependent on whether it arises and you won't see the same thing from every frame of reference nor could you claim that one particular velocity was more real or not or even declare that he is actually at rest when in other frames of reference he is moving. If this was purely a perceptual effect then we would think this wouldn't be accompanied by clear dynamical and kinematical issues involved with taking measurements. . . course you could mathematically reproduce this understanding with a classical theory of literal length contraction (as well as a counterpart one with no length contraction but finite speed of perceptual effects) and compare. . . to you know. . . show who is right.
  7. That's fine. . . simple mistakes pail in comparison to those regarding our fundamentals.
  8. \[ \begin{bmatrix}a & b\\c & d\end{bmatrix}\]
  9. In the description is declares that it's a row of dice moving. Not a single (die) pictured at different times while it was moving if I recall correctly.
  10. How about you go through the mathematics and create an image plane with the relativistic object having its light happen to reach some focus then figure it out. It's difficult and perhaps not actually correct to analyze some image analysis as has been given as we do not know what the units were nor whether your naive perceptual decision on what is longer is truly correct. Should the image of a cube appear larger than it should in the way you claim or is this not what special relativity would predict optically? Remember, no "I think it would look like this," just do the mathematics or perhaps wait for some one competent in that respective to show it in a simplified situation. A simple imaging plane and a focus will construe the image like that as objects farther to the left will appear more scrunched together i'm assuming. . . we're talking about what you would see optically. In fact. . . just you wait as i'll perform the some mathematical investigation into this but derived via some simple vector mechanics with objects being focused unto an imaging plane with a focus. Then we can compare the images showing that those objects farther away parallel wise to the imaging plane do seem to have their distance scrunched up even if we happen to possess an equally dispersed series of lines in reality. Glad you admit your fault and you must please understand that you should not use your intuition as if it's a judicial gavel of physics as even in CLASSICAL PHYSICS with optical imaging i'm willing to bet we could both make similar mistakes in thinking if we didn't actually do the proper mathematical preliminaries to derive how things would actually play out. I'll attempt to get back to you as soon as possible for the classical then the special relativistic case with all proper mathematical foundations. I'll be using equally spaced constant velocity rods then for both the classical as well as the relativistic to compare.
  11. You would think this if you didn't consult the spacetime interval in which \( s^{2} = (ct)^{2} - x^{2} = (c\tau)^{2}\). NOTE that the traveler happens to have a longer path through spacetime and together with the objectively long path they traveled in space some of that distance in SPACETIME that they happened to traverse has some of that temporal component eaten up by the distance they traveled. The spacetime interval for the person at rest is: \[ \tau = t_{person at rest} \] For the twin who (because he was non-inertial) was objectively traveling a longer path through spacetime they started and ended the journey at the same spot yielding in terms of the rest frame time \( \tau \) or it took \( \tau \) time for them to leave then come back: \[ (c\tau)^{2} = (ct_{traveler})^{2} + x^{2} \] They traveled objectively some certain distance \( x \) and using your knowledge of pythagorean theorem you notice that the length of the one side (the time by the traveler) couldn't exceed the length of the two others. Objectively given they traveled away there was no way the time of the traveler could in fact exceed or even equal that of the time given by the clock at rest if it must abide by special relativity and likewise the spacetime interval. \[ t_{traveler} \neq \tau \] @joigus Did I do this right? Always bound to come across somebody like this on any forum. . .
  12. The arm does look smaller or larger depending on your perspective. . . but if you actually made a measurement and sent a light beam (or a radio signal or even used a measuring rod that was at rest with respect to your arm) you would happen to find the length had remained unchanged in BOTH situations. So. . . no length contraction. . . bad analogy. When you talk about the laws of perspective being independent of Relativity note the difference between what a camera or perhaps even a human being could potentially see and what kind of raw measurements we could make in which these sort of perceptual effects wouldn't come into it. You get the SAME PERCEPTUAL effects in CLASSICAL PHYSICS and we rightly so do not designate them as actual length changes but this is because of the specific collection of dynamical/kinematical laws we are assuming to then analyze this. The same is in special relativity in which length contraction is usually treated as the sort of frame dependent observation that is consistent with Lorentzian transformations while what you would see is (c) instead of (b) so you CANNOT go off of pure visual observations so to speak to find this contraction but you would measurably notice it in special relativity, Not only that. . . are you just going to ignore the meat of my previous posts. . . anything to say. . . the laws of optics are not ignored in special relativity rather they are amended yielding the above image (c) rather than the classical optical image (e). If you desire to chalk it up to CLASSICAL OPTICS then please be my guest and explain how this can be the case that in special relativity we seem to measure/record lengths as being shorter when in reality they are not supposed to be but we measure them as. Further, there isn't entirely something wrong with the philosophical question of whether it's the dynamical laws that give rise to or are fundamental to the kinematical ones or vice versa as other philosophers in spacetime philosophy have claimed that dynamical symmetries must be symmetries of spacetime. Dissenters have argued that we should flip the arrow of explanation from the kinematically explaining dynamical laws (spacetime structure -> dynamical laws) to seeing them as rather fundamental (dynamical laws -> spacetime structure). The question then of whether the Lorentz length contraction is more real in one perspective or the other one isn't really a question that would get a wrong answer in this situation as if we emphasized dynamical considerations then the objects from other perspectives do contract seemingly (dynamical laws require us to measure them as shortened) or it's the spacetime structure that results in our. . . wait for it. . . length measurements to result in being shorter. In either situation it wouldn't be any less real or entirely more perceptual.
  13. So true numerous different misconceptions in relativity or perhaps other areas of physics could be alleviated with sort of thinking. The time it has to travel as well as where and when it was emitted as even in your frame of reference in special relativity it's perfectly possible to imagine being in the cube's frame to emit light equally in all directions at the same time but others will not see it in the same manner you would expect. You know I think you may be rather right in your speculation but i'd have to investigate further mathematically. @md65536 Also. . . Steins Gate. . . NICE!
  14. Please do so but i'm not sure I trust you with deriving the visual results from special relativity on what you would see so when you get there stick to classical physics. . . unless you can show us the mathematical rigor needed. Yes, there is also a classical assumption that would play into this and give rather predictive results as to how it would exactly look. Cut your teeth on this article I found. Hmmmm. . . I found it! There is a difference between length contraction (measured) and what is observed which respectively would be (b) versus (c) as well as what you would expect with naive classical physics (e). (a) A row of dice at rest moving from left to right in a single file at 95% of the speed of light. (b) The moving dice are length contracted, so that one might (wrongly) expect them to look as here. (c) If you actually observe the dice, however, they will appear rotated. (d) But when some perception in depth is provided, you’d see them as sheared rather than rotated. (e) Shown here is the predicted “classical” appearance of the dice, with no length contraction. You can view a short film of part c online here. (Courtesy: U Kraus 2008 Eur. J. Phys. 29 1) You better have read the articles above and looked at the image as well as considered that there is a strong difference between what length you measure an object to have and distorted image you see.
  15. It does only happen in the direction of motion as is or would be derived from the Lorentz transformation. If you have some other mathematical model to propose in which the object doesn't just contract in the direction of motion but in every direction equally or by some function of the velocity be my guest. . . propose it and test it. Further, "time dilation has no direction" why does this have to be a problem. . . why is this a problem for length contraction? Again you can propose some inhomogeneity or anisotropic effects that if a clock went in one direction it would slow more than in another in a round trip. . . be my guest in mathematically realizing this and testing it. You cannot just assume there is this immaterial Newtonian Clock that ticks throughout the universe and some how also minimally interacts with everything in the process assigning a precise time measurement anywhere in the universe. . . you cannot just claim this by fiat. Further, you literally DO NOT HAVE TO LEAVE GALILEAN RELATIVITY or classical physics to have your "multiple realities". Remember the Galilean transformation? Through this transformation you can transform from one INERTIAL frame to another without issue and thusly could show that the laws of physics (conservation of energy/linear and angular momentum) were followed in both frames of reference just as YOU will see the other frame moving away from you with some velocity (they are not identical frames of reference then) according to your frame of reference. . . wait. . . but the velocity was opposite that way in the other inertial frame of reference. . . which is the right velocity? In which the answer to said question is that this is a nonsense question as only a velocity assigned to a particular frame of reference (even the almighty stationary one) is what matters as you can only ask what velocity an object has with RESPECT to a particular frame of reference. In special relativity this idea is merely extended to measurements of lengths as well as clock ticks seen from your frame of reference. Again, you do not need to leave classical physics to see the fault in seeing this as a problem. Imagine you have a spaceship and a lone spaceman out in the middle of space at rest with respect to each other. The spaceship rockets away accelerating up then slows down to speed up in the opposite direction before slowing down again to enter the original frame of reference it resided in at the beginning. You both ask each other who really moved? First Person: I clearly didn't as I saw you speed away and during the whole time I remained at rest with respect to myself. I wasn't moving. Second Person: But I also saw myself as at rest the whole time. When you think about it kinematically and visually they both have some grounds to consider themselves both correct as there space-time diagrams would show similar but oppositely oriented collections of parabolic curves. To alleviate the issue we decide to mount an apprautus to the spaceship that is basically a small ball within a larger ball where the smaller ball is floating freely but the larger ball is attached to the spaceship. If we accelerated forward then the freely floating ball would just slowly float in the air until the now moving outer surface closed the distance and then impacted it. If we were in an inertial frame of reference the whole time then clearly the ball within there would just float as you would expect via our classical understanding of physics and inertial frames of reference (frames without any induced forces). You then both repeat the same experiment and predictably the floating spaceman would never notice any forces (fictitious or real) creep into his frame of reference while those in the spaceship would see their smaller ball begin to move as if some force was exerted on it but (assuming they accounted for all other forces) this cannot be as it clearly must remain inertial as we accounted for all forces. The only real answer is that a force was exerted on the spaceship which gave rise to our fictitious force on the ball. Thus the paradox is solved. . . the spaceship was the one that moved. With two inertial frames of reference (one moving away at constant velocity) you couldn't really do this because the paradox requires the frames come back together and if they both accelerated away then came back together they would still see the fictitious forces arise in their respective frames of reference. Just as in Galilean or classical physics there is NO RELATIVITY OF NON-INERTIAL FRAMES OF REFERENCE so is the case in special relativity because. . . you know. . . its first postulate is that all inertial frames of reference are equivalent not ALL NON-INERTIAL FRAMES OF REFERENCE ARE EQUIVALENT or ALL FRAMES OF REFERENCE ARE EQUIVALENT. Which would be required for the twin paradox in that one of them has to turn around so to speak or both equally turn around but in the process in both situations their are people objectively changing inertial frames of reference. In the later case, however, given they accelerated for the same amount of proper time (slowed then speed up to come back) they would have identical world lines and there wouldn't be any net time difference with respect to each other when they re-enter the original inertial frame of reference because they would be entirely symmetric. . . the people in the original frame of reference however would notice that they were both equally younger assuming they remained inertial (we could as an experiment or mathematically set up a similar ball apparatus as before). This is an issue I see all the time in people trying to grasp relativity. In the theory (with minimal ontological assumptions of Minkowski spacetime) while you have this effect of length contraction that is rather mathematically explicit even by theory or ontology what you would actually observe is something like. . . In fact I'm pretty sure there is even a further different classical perspective of the cube that you would expect which does differ from the visual image seen above that special relativity would, being approximately correct, in the end expect. @swansont How'd I do?
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