Sr Definition and 480 Threads

  1. J

    Magnetism and radiation as a consequence of SR

    Please refer the doc attached. The document is available at http://physics.weber.edu/schroeder/mrr/MRRhandout.pdf It explains magnetism and radiation as a consequence of SR. In the section for magnetism, it is depicted that, with respect to test charge Q, the distance between the -q...
  2. S

    Einstein and the Speed of Light: Exploring SR's Resistance to Acceleration

    SR tells us that at the speed of light, time stops, your length contracts to nothing, and your resistance to acceleration becomes infinite requiring infinite energy... according to an stationary observer. But! How do we know that observer is stationary, and it is not him who requires...
  3. J

    Discover the World of SR and GR Theory: Free Resources and Expert Tips

    Hi I have a great inerest in SR and GR.As I am in quite learning stage I have started reading docs regarding this from internet. Presently I am reading a book 'Introduction to special relativity' by Robert Resnik. Is there any FREE book available on net on this subject or tell me the way I...
  4. G

    Time Dilation in SR: Exploring the Speed of Light and Spaceship Movement

    A spaceship is moving, then it launches a ray of light behind itself. if time in the spaceship is slower than in other frames that are moving less fast, shouldn't the ray appear much faster than c? this thing works with a ray launched in front of the ship, but behind, shouldn't the time go...
  5. E

    Time in SR and relativistic mass

    Is it possible substitutive explanation of SR: "because of larger relativistic mass everything moves more slowly." I tried to to get this substitution mathematically, but it not works. I know that lorentz contraction should be included as supposition that things work. For instance: a =...
  6. S

    Can SR fully explain magnetic force?

    As we know for over 100 years magnetic force in an relativistic effect caused by the movement of charged particles. Let’s take the standard example - current in a wire. If a charged test particle (say electron) is moving relative to the wire it feels the Lorentz force. I can understand...
  7. A

    Does the Twins Paradox Always Hold True for Inertial and Non-Inertial Observers?

    Let's say we have a ship following a buoy toward earth. The ship and buoy are at rest relative to each other, a distance of 10 light years apart, in the ship's frame. The distance between the ship and buoy is 5 light years in Earth's frame. They are approaching Earth at a relative velocity of...
  8. A

    A question about the rationale of SR?

    Hello, I have a question about special relativity. According to the Lorentz transformation, if a coordinate system K' is moving with respect to a coordinate system K, then a rod fixed with respect to K' will appear to be more lengthy with respect to K than that with respect to K'. The...
  9. A

    When and where will ship A turn around according to an observer on earth?

    OK, can someone answer this for me? Let's say we have two spaceships, Ship A and Ship B, traveling toward Earth at v= 0.866c relative to earth. They are at rest relative to each other, not accelerating, and Ship B is at a distance of 5 light years behind Ship A (as observed by them). They...
  10. L

    Can SR be derived from other postulates than the constancy of c

    The usual foundation for deriving SR is the constancy of the speed of light. Are there other ways to derive SR, and eventually some more general? Have you ever read something about that? Thanks, Michel
  11. N

    Can Muon Decay Experiments Disprove the Existence of an Absolute Time Frame?

    I'm coming at this from the perspective of something that might be used in a general discussion piece on SR, or maybe the introduction part of a (low level) course. One concept that's often difficult for newcomers to grasp is the lack of a 'God Frame'. It comes up in several ways, one of...
  12. V

    Is Relativity an Illusion or Reality?

    The fundamental mistake in SR is making a direct comparison between the movement of objects and the movement of light. If we take into consideration the fact that the light simply can not have a zero speed, these are different. Maybe there is a more profound explanation of why this...
  13. M

    Defining Special Relativity & General Relativity

    The other day, I was trying to explain what SR & GR were for some non-science friends of mine. I started speaking of motion with constant speed, the postulates of SR, the spaceship and the ball, time dilatition, twin paradox and so on. Needless to say, they didn't understand what I was talking...
  14. R

    If SR Wrong: Difficulties, Paradoxes, Instantaneous Signals

    If SR were wrong, in what kind of difficulties and paradoxes would we run? What would an universe with instantaneous signals look like? Is such universe even possible? thanks
  15. F

    Understanding Kinetic Energy in Special Relativity

    In normal mechanics, the kinetic energy is the integral of the momentum with respect to the velocity ( \int m_0v.dv . So, why is the kinetic energy not given by \int \frac{m_0v}{\sqrt{1 - v^2/c^2}}dv? Sorry it took a few edits to get the maths looking right.
  16. T

    GR, SR and the Sagnac effect question

    I've read in multiple locations that GR is necessary to properly explain a co-rotating perspective/observer of the experiment. Additionally, SR can explain the experience of non-inertial observer. The above two statements seem somewhat conflicting and leads to my question. Why is it that...
  17. daniel_i_l

    Think about SR as different observers using different coordinate

    Is it correct to think about SR as different observers using different coordinate systems depending on their speeds? This would meen that their measurements would differ since space, time, mass,etc.. measurements depend on the system used. I find it very easy to understand SR when I think...
  18. D

    Is it possible to derive Lorentz-transforms through geometric methods?

    Has anyone derived the Lorentz-transforms by using 'simple' geometrics? If so, could I get a link for the paper please. I tried to google for one but couldn't find.
  19. Reshma

    Some conceptual questions on SR

    I need to clear some conceptual doubts in the Special theory of relativity. So could anyone explain them in context to the following questions: 1. The speed of light in glass is 2.0 x 108m/s. Does it violate the second postulate of SR in any way? 2. A uniformly moving train passes by a...
  20. Ε

    Einstein's Quest for Unifying SR & GR with EM

    Alright, so Einstein came up with SR to make Maxwell's EM consistent with dynamics, correct? But SR was only for non-inertial reference frames and ignored gravity, so it was replaced with GR to make SR consistent with gravity. So why have I read (from many sources) that Einstein spent his...
  21. P

    Henri Poincaré: The Real Discoverer of Special Relativity

    Why isn't the mathematician Henri Poincaré acknowledged as the true discoverer of special relativity? http://www-cosmosaf.iap.fr/Poincare-RR3A.htm http://arxiv.org/abs/physics/0408077
  22. P

    Time Dilation & Generalization of SR: Beyond Light

    How has it been shown that time dilation is not a property of light? I've only seen the equation derived from a light clock or something dealing with light. How can time dilation (along with other predictions of special relativity) be generalized to everything as a property of time itself?
  23. G

    GR vs. SR while accelerating away

    A quick question for those fast with the GR and SR math. Assume you get in a spaceship and start accelerating away from Earth, and during the trip you and the people left behind compare clock speeds periodically (not elapsed time, but rather tick rates). At what combination of acceleration...
  24. S

    Information needed on two wheels and chain apparent paradox in SR

    I hope someone can point me to some information to assist resolving this apparent SR paradox. I have two gear wheels with an endless chain passing round them. The axles of the wheels are 100 chain_link_lengths apart, so we have 100 chain links along the top; 100 chain links along the bottom...
  25. C

    Are SR & GR Considered Experimentally Proven?

    I know a bit about evidence supporting special relativity (muon decay, synchronized cesium clocks, etc.) and general relativity (perihelion of Mercury, etc.). BUT - is SR and GR considered "proven" or, in the minds of mainstream physicists, is the jury still out?
  26. M

    A wrong statement regarding SR.

    I've had a friend who said this "However, all objects can be considered immovable relative to the speed c, since the speed remains constant relative to all objects and so it seems like all objects remain stationary comparing with this speed." There's a nagging feeling at the back of my head...
  27. T

    How Can I Use My Spaceship to Reset My Clock?

    I don't know how to reset the time on my clock, but I do have a spaceship that can go as fast as 0.9C. How fast and how far will I need to go this weekend to properly reset my clock. :smile: The Rev
  28. T

    How does the weight of a rock change in relativistic speeds?

    I'm pretty new to the ideas of relativity, so maybe this is old ground to cover for some of you. However, I need to know how to resolve an apparent paradox. Person A is traveling at relativistic speeds holding a stone over his head. The stone weighs just slightly less than the maximum...
  29. Pengwuino

    SR problem, howd they get here?

    So the question is basically an unstable particle at rest breaks into 2 fragments. m1 = 2.50 x 10 ^ -28 m2 = 1.67 x 10 ^ -27 v1= 0.893c whats v2? So it gets to a point where they ahve... yxm2v2+ ((2.50x10^-28kg)/(sqr(1-0.893^2)))(0.893c)=0 Now why is that square root "1-0.893^2"...
  30. Andrew Mason

    Why can't SR explain why electrons do not crash into the nucleus?

    In a recent discussion in this thread I wrote: Using classical mechanics and electomagnetism, work out the speed that an electron would have to have in order to orbit a hydrogen nucleus at a distance of 10^-12 m: F_c = \frac{m_ev^2}{r} = \frac{kq_e^2}{r^2} v = \sqrt{\frac{kq_e^2}{mr}}...
  31. D

    Exploring Space-Time & SR: Why so?

    In http://www.freewebs.com/mouldy-fart/Space,%20Time%20and%20SR.pdf paper the author wrote: t'=\sqrt{\frac{4h^2}{c^2-v^2}}=\frac{2h}{\sqrt{c^2-v^2}} t'=\frac{2h}{\sqrt{c^2}}\frac{1}{\sqrt{1-\frac{v^2}{c^2}}} Why so? Also, isn't the relativistic beta considered just v/c, not as the...
  32. M

    RF SR: What If I'm Anchored to a Moving Train?

    What if I am in a RF, S, anchored to the ground, and there is another RF S', which is anchored to a train. According to my RF, the clocks in the train moves slower, but according to S', does my clocks move slower too?
  33. Hans de Vries

    Aspect/Innsbruck Interpretation which respects SR locality

    -- -- EPR experiments seem to show a significantly higher correlation rate in the detection of separated photons which are in an entangled state. From the measured correlation we may or may not want to draw very fundamental conclusions. One such a far reaching conclusion would be that...
  34. Y

    Does Special Relativity Suggest a Predetermined Future?

    Came across an article of interest claiming SR implies the future is predetermined. The salient argument is summarized below: We start with the notion that we cannot attribute reality to the future since it is yet to be determined. Nor can we claim that what we see is real in the present...
  35. C

    What I tell laymen who ask me about SR

    I tell them: (first, explain spacetime) "Relative to anyone else, we move through space-time at the speed of light. Take you and I standing here, you are not moving in space relative me so I see you moving through time at the speed of light. If somebody flew past at near the speed of...
  36. J

    Note the comment on SR herein:

    With the appearance of the general relativity theory, it became increasingly difficult for other disciplines to “map” their own terms of art to those of relativity in an internally consistent fashion. But we know now that, previous to the appearance of the general theory, it was attempted very...
  37. D

    Explaining Special Relativity: Increasing Resistance to Acceleration

    I was reading about special relativity on How Stuff Works. In the article, the writer has given the following 4 points: 1. Energy must be added to the system to increase the ship's speed. 2. More of the added energy goes towards increasing the system's resistance to acceleration. 3. Less...
  38. quantumdude

    Aether theories which are experimentally indistinguishable from SR.

    From John Baez’ page on the experimental basis of Special Relativity, he says that: and My question pertains to the remarks in blue: aether theories that are experimentally indistinguishable from SR. Where are these theories published? One member (Yogi) makes reference to the so-called...
  39. I

    Does mass increase in SR mean higher gravity in GR?

    It has been years since I have thought of relativity, but I came across a book by Jerome Drexler in which he attempts to support his view that ultra high energy protons (cosmic rays) are what dark matter is all about in the galactic halos. In spite of the fact that it seems to me these protons...
  40. J

    What if the guy on the train throws the ball backwards (u'=-.99c)?

    A train is moving to the right at v=.5c. Someone standing on the train throws a baseball forward (to the right) at u'=.99c (relative to him). Relative to somone on the ground, the ball appears to be traveling at a speed u which is slightly faster than .99c, but still less than c. What if the...
  41. Curious3141

    Is it Possible to Resolve the SR Time Dilation Problem? Help Needed!

    Please help me resolve this problem. Suppose we have 3 objects traveling at constant velocity, and hence 3 inertial frames of reference. Call them object A, B and O respectively. O is at rest with respect to the observer. Let the relative velocity of A from the point of view of B be speed...
  42. B

    Many Worlds Interpretation of SR

    Special Relativity predicts that moving clocks run slow, mass and length are variable and simultaneity is relative. These are 'real' phenomena and leads me to think that the reality of one observer (the passing of time, all physical properties and space-time events) can be regarded as 'his...
  43. P

    Testing SR with a Rotating Mass: Experiments & Theory

    What if someone set up an experiment, where they sped up a mass of high density in a circle ethier by making its radius smaller and smaller, until the large mass is moving near the speed of light, then at an extremely small highet above this rotating mass you set off a high frequency laser...
  44. P

    What are your favorite web pages on SR?

    What are your favorite web pages on special relativity and why? I'm looking for exemplary pages that represent orthodoxy and excellence. Thanks. Photon A
  45. B

    Experiments performed that upholds the predictions of SR?

    what are some of the experiments performed that upholds the predictions of SR?
  46. JasonRox

    How does speed affect perceived time in David W. Hogg's SR Book?

    This is a question in David W. Hoggs SR Book, so it is not homework. Problem 3-4 A rocket ship passes the Earth at speed B = 0.8 (B=v/c). Observers on the ship and on Earth agree that it is noon. Answer the following questions: a)At 12:30pm, as read by a rocket ship clock(assuming it is...
  47. V

    Why are the fundamental postulates of special relativity controversial?

    could someone be kind enough to explain to me why the fundamental postulates of special relativity introduced thanks
  48. T

    Quantum blended with a little SR

    Is this a paradox between QM and SR: If two particles say electrons are in the same quantum state then no matter what the distance if one "flips" then the other one does the same thing, because they are tricked into thinking they are right next to each other, however SR strictly implies...
  49. G

    Are QM and SR completely compatible?

    Hi, correct me if I'm wrong, but quantum mechanics and special relativity seem to fit pretty well together. With Klein-Gordon's equation and Dirac's equation anyway, they seem to be able to live with each other quite happily. Are there cases in which they can't? Is this what Q Field theory...
  50. J

    Train Experiment: Does Simultaneity Depend on Frame of Reference?

    About that train experiment. Everyone probably knows the story. For the person on the train, the flash of light hits both ends of the train at the same time. For the person watching on the embankment, the flash of light hits the back end of the train first. Now, I'm reading a book on SR...
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