Special relativity Definition and 1000 Threads

  1. M

    Time Difference between two inertial frames of reference

    Homework Statement Let S and S' be two inertial frames of reference where S' is moving at a velocity of 0.6c relative to S. When x = x' = 0, t = t' = 0, where t and t' are time of the clocks on S and S' respectively and x and x' are the x-coordinates of the S and S' frames respectively. An...
  2. S

    General relativity vs special relativity

    Hello, Everybody! I'm new to the board, and am happy to have found you! I have six questions I can't seem to find the answers to, either in books or online -- yet I know the answers are out there! I'll post each question in a separate thread, and hope that someone who knows far more than I do...
  3. U

    Compton Scattering Angle - CM FRAME

    Homework Statement Given incoming photon has energy 10Mev and scatters at angle 25 degrees, find the scattering angle in CM frame. Homework EquationsThe Attempt at a Solution [/B] In lab frame, let the energy of incoming photon be ##E##. Total 4-vector would be ##P + Q =...
  4. U

    Lorentz Transformation of relative velocity

    Homework Statement If two particles have velocities u and v in frame S, find their relative speed in frame S'. Homework EquationsThe Attempt at a Solution Isn't it strange that the relative speed doesn't depend on the velocity of the frame, ##\vec s##? Since the two particles have velocities...
  5. U

    Two particle collision - One in excited state

    Homework Statement (a)Find energy of photon emitted (b)Show that relative velocities after de-excitation are reversed (c)Find an expression for CM frame energy and find momentum of either particle in CM frame (d)Consider now, for a nuclear process and describe the initial and final conditions...
  6. S

    Relativistic relative velocity of particles

    Homework Statement In a given inertial frame two particles are shot out simultaneously from a given point with equal speeds u at an angle of 60 degrees with respect to each other. Using the concept of 4-velocity or otherwise, show that the relative speed of the particles is given by ##u_R =...
  7. C

    Lorentz Transformation - Clock

    Homework Statement Use the Lorentz Transformation equations to derive the formula relating the time period of a moving clock to that of a stationary clock Homework Equations X'=y(X-vt) Y'=Y Z'=Z t'=y(t-vx/c^2) The Attempt at a Solution t'=1/sqrt(1-(v/c)^2) . (t-vx/c^2)
  8. T

    Special relativity and the speed of light constant

    Hi guys. I know that light does not travel through time. Is that because its speed is constant for all observer?
  9. D

    Fizeau's Experiment interpretation

    Hi all,In Einstein's book, "Relativity: The Special and General Theory", he uses the Fizeau experiment to show how the Lorentz Transform correctly predicts the addition of velocities. I have some difficulty understanding the interpretation of the results, however. Suppose that liquid M is in...
  10. D

    Understand Relativity & Lorentz Transformation - Aaron

    Hi all,I am trying to understand relativity and Lorentz Transformation more clearly but I have some problems. Assume that we have frame F' which is moving at velocity v with respect to F. Now assume we have an object, O, moving at velocity, w, with respect to F. Frame F has its own time, t, and...
  11. LachyP

    Who wants a chat? Preferably about Physics

    Hello, I'm Lachlan Pearce and love physics (mostly special relativity, astrophysics, and a little of quantum physics). If anyone wants to discuss any of this I'd be happy to.. :)
  12. Amaterasu21

    Question about time in QM vs. special relativity?

    This question is about both quantum mechanics and special relativity, so I wasn't sure which forum to post it in. If mods think it's in the wrong forum then please move it as you see fit! My understanding is that in special relativity, we live in a four-dimensional "block universe" of...
  13. Alettix

    Relativistic Work: Deriving Formula & Application to Electrons

    Hello, I have tried to derive a relativistic formula for work using the E = ϒmc^2 equation and that work is equivalent to change in energy. But I have not gotten especially far and everything is messy. However, when looking at solutions to some harder problems I encountered the formula...
  14. V

    Special relativity help - force

    Homework Statement A claim is made that a new force field F(x) (independent of the four-velocity) is discovered which induces on a mass m a 4-acceleration a = du/dτ = F(x)/m at position x. Would this be consistent with special relativity? Why or why not? Homework EquationsThe Attempt at a...
  15. QuantumCurt

    Special Relativity: Trip to Andromeda by rocket

    Homework Statement This is from chapter 1 (2nd edition) of Taylor and Wheeler's 'Spacetime Physics.' It's a four part problem, and I didn't have any troubles with parts a, b, or c. I'm stuck on part d. I'm supposed to determine if we could make it to Andromeda within a lifetime. Assume that...
  16. Gravity

    Does Penrose's Andromeda paradox prove determinism?

    Article: https://en.wikipedia.org/wiki/Rietdijk–Putnam_argument
  17. U

    Deriving Equation 4.8 in Special Relativity: Tips and Tricks

    Taken from Steane's "Relativity made relatively easy" equation 4.8 I have been trying to show (4.8) using these relations earlier on in the book: Tried most means (rearranging, taking dot products) but can't seem to make it work. Is there an easy method I'm missing out?
  18. M

    Special Relativity and time dilation

    Homework Statement Two spaceships are traveling with a relative velocity of 1.2x10^8 m/s, both carrying clocks. According to the captain of each ship, the other captains clock ticks more slowly than his own. By what factor do the clocks disagree? Homework Equations 1/(1-(v^2/c^2))^1/2The...
  19. kq6up

    A Book that Clearly Explains Special Relativity w / Tensors?

    My professor gave us a book that is still in production to use for special relativity. I am having a hard time grasping the notation and operations with Einstein upper and lower notation. Can anyone recommend a good textbook on this topic? Chris
  20. A

    Special Relativity and the Relativity of Simultaneity.

    The position of the rocket is not specific. We just know that it is at the left of the galaxy. We know that R will explode first in the rocket's frame. Maybe the galaxy could be moving fast enough so that the time it takes for L to explode is enough for the rocket to see R's light first. In...
  21. B

    How Does Time Dilation Affect Communication and Aging in Space Travel?

    Hello, I am doing my special relativity homework and since the ideas are quite counter-intuitive it's hard to know if I'm doing the right things. So i'd like to post some work here and see if it is correct. Also, I am stuck on the final part of the question. 1. Homework Statement A space...
  22. M

    Geometry of Time Dilation

    I was recently exploring time dilation from Gravity and from velocity and I came up with an interesting derivation that I have not seen before. I was wondering if there is a paper published showing these relationships like this before and where I could find it? First you start with the...
  23. MiladP

    Does the weight of a relativistic mass change when measured on a moving scale?

    Consider two equal masses, m, are placed on two identical scales in a uniform gravitational field. If one of the masses moves with relativistic speed, does the moving scale read mg or γmg? Why? It seams that people used to call γm the relativistic mass where m is the rest mass. However, more...
  24. StonedPhysicist

    Muon special relativity problem,

    Here is the question: If 1000 muons are incident from a height of 10 km above the Earth's surface, how much slower than the velocity of light must they be traveling in the rest frame of the Earths surface for 990 of them to be expected to arrive at the ground undecayed? The mean life of a muon...
  25. N

    Calculating Time for a Swimmer to Cross a River Using Pythagorean Theorem

    Homework Statement A river is 400 feet wide and flows at 1 ft/s. A swimmer swims at 2 ft/second, straight across the river and back to where he started on the original shore. Find the time required to complete his trip. To clarify, the turn around point is straight across the river. (I have...
  26. F

    Special Relativity - "Simultaneity"

    Homework Statement An experimenter triggers two lights simultaneously, which produces a large flash located at the origin of his reference frame and a small one at x = 23.8 km. An observer, who moves with speed 0.374c in the positive x direction, also views the flashes. What is the time...
  27. F

    How Fast and Slow Does Time Flow on a Speeding Spaceship?

    I was not too sure if this was the correct forum, so feel free to move if needed. 1. Homework Statement A spaceship is measured to be exactly 1/3 of its proper length. (a) What is the speed parameter β of the spaceship relative to the observer's frame? (b) By what integer factor do the...
  28. dbmorpher

    Velocity of an Electron from Momentum

    Homework Statement If I know the momentum and mass of a particle how do I determine/differentiate the Lorentz Factor and velocity? Electron rest mass: 9.10938215e-31kg c=299792458m/s y=Lorentz Factor m=mass p=momentum e=energy Calculated momentum: 2.019006271e+14kg m/s Homework Equations...
  29. Strilanc

    Distinguishing Special Relativity from Classical Mechanics

    I was recently reading the strange world of classical mechanics. It prompted me to calculate some round trip times for things moving near the speed of light (classically, with an aether). I found that the predictions it makes are awfully similar to relativity, and I can't think of an experiment...
  30. applestrudle

    Special Relativity Time Dilation Santa question

    I am doing a presentation and want to make sure I'm not misunderstanding something very fundamental. My argument goes like this: t0 = ϒt Santa is moving very fast and from his point of view he is in proper time. This means that if it takes him t0 seconds to deliver a present, the amount of...
  31. A

    Special Relativity, French, solutions manual

    I'm currently reading Special Relativity, the famous book on this subject by French. The book does contain a nice set of problems for each chapter and corresponding answers at the end of the book. The issue I have with the answers though is that they are mostly just the correct answers, there...
  32. adoion

    Was Einstein lucky when not considering twin paradox as paradox?

    hi, Einstein did not even consider the twin paradox as problematic at all, he argued that it is a simple consequence of his special relativity? obviously he never gave a explanation of why the two twins don't age the same he instead left it to others to do so. was Einstein just having a hunch...
  33. M

    Around the Earth Clock: Does Special Relativity Hold True?

    Hi all I just started doing some research on special relativity and I figured something. If two people both reset their watches. One person goes around the Earth once, doesn't matter at what speed, and the other person stays there. The watch of the person that went around the Earth will run...
  34. K

    Velma and Mort's ice cream is melting special relativity problem. Help please.

    Homework Statement Velma and Mort have identical 10-minute melting ice-cream cones. How fast must Velma move in order for her 10-minute cone to last 3 times longer than Mort’s, as measured by Mort?Homework EquationsThe Attempt at a Solution [/B] We have not gotten too in depth into...
  35. K

    Special relativity question: space travel and relativity of time

    Homework Statement You are 20 years old and embark on a mission to a star system that is 200 light-years away. Your ship leaves Earth in 2013 and travels at 0.999c. You do not spend much time at the destination, just head back to Earth. What year is it when you arrive back on Earth? How old...
  36. X

    Do entangled particles decay simultaneously?

    I apologise in advance for my rather minimal knowledge of physics. Please assume that anything I write below is just my current understanding, and may very well be incorrect... Elementary particles decay into other elementary particles. When a a subatomic particle decays into a pair of other...
  37. J

    Velocity of Accelerated Observer in SR: Understanding the Paradox

    Hey, I have a question regarding accelerated motion in special relativity. Suppose an observer has a constant proper acceleration α, his velocity in an inertial frame of a distant observer will then be given v = c tanh(ατ/c), where τ is the proper time of the accelerated observer. Since every...
  38. R

    Precession of relativistic orbit in pure inverse-square force

    PROBLEM: Show that Special Relativity predicts a precession of π(GMm/cl)2 radians per orbit for any elliptic orbit under a pure inverse-square force. where G is gravitational constant, M is mass of larger body, m is mass of smaller orbiting body, c is speed of light and l is angular momentum...
  39. V

    Minimal Special Relativity - Reciprocity of Time Dilation

    Hello, I hope somebody can help me with this question. Homework Statement I have to prove that time dilation is a reciprocal effect by only using the Postulates of Minimal Relativity Theory: 1. Let I be an inertial frame, then I' moving with a constant velocity in a rectilinear motion with...
  40. K

    Special relativity and relative motion question

    Homework Statement Hello all, I have a couple of questions that I am a little unsure of. Could you please let me know if my answers are correct? But more importantly could you let me know if my reasoning is correct? Thanks in advance! 1. Mort stands on Earth. Velma moves away from him in a...
  41. S

    Maximum rest mass in particle collision

    Homework Statement Suppose that a certain accelerator can give protons a kinetic energy of 200 GeV. The rest mass of a proton is 0.938 Gev/c^2. Calculate the largest possible rest mass M0 of a particle that could be produced by the impact of one of the high-energy protons on a stationary...
  42. A

    Special relativity - time dilation

    Consider two events that take place at the origin of the frame of an inertial observer O' . At times t_1 ' = 0 and t_2 ' = T . O' moves with a constant speed v w.r.t. another inertial observer O . 1. Use the Lorentz-transformations to show that these events occur at x=vt in the frame...
  43. R

    Special Relativity Equation: Is This Accurate?

    While surfing the internet, I came across a statement that this is the equation for special relativity: Line 1: x = a + b Line 2: x = a + b (c2/c2) with c = speed of light Line 3: x = a + (y/c2) if y = b(c2) Is this really the one? If not, is it relevant at all?
  44. C

    Special Relativity as a source of Power?

    Hey guys, I've recently learned that magnetism is an electric field viewed from a different frame of reference and that the mathematics of electrodynamics describes this. However something raised my eyebrow which I wasn't quite clear on. If energy is put into a net flow of electrons, the...
  45. P

    General and special theory of relativity in few words

    How can I explain to someone who has only high school level of education in physics, what is general and special theory of relativity about? Each of them separetelly in one or two sentences please. General theory of relativity … Special theory of relativity ... Thank you.
  46. F

    Special Relativity with 2 light beams moving towards each other

    Homework Statement If one light beam is heading toward you from the right, and another is heading toward you from the left, how quickly from the perspective of the right-moving beam is the left-moving beam approaching it? 1) 0 2) c 3) 1.5c 4) 2c Homework Equations (v+w) / (1 + cw/c2) The...
  47. I

    Special Relativity transformations

    Homework Statement A rod of rest length 1,0m is moving longitudinally on a smooth table with a velocity 0,8c relative to the table. A circular hole of rest diameter 1,0 m lies in its path. The diameter of the hole as seen by the rod is going to be larger?Homework Equations The Attempt at a...
  48. D

    Special Relativity: Velocity Addition

    Homework Statement Two objects fly toward you, one from the east with speed u, and the other from the west with speed v. Is it correct that their relative speed, as measured by you, is v+u? Or should you use the velocity addition formula, V=(u+v)/(1+uv/c2)? Is it possible for their relative...
  49. M

    Independent Study: MIT OCW-Based Relativity/ Special Relativity

    Hi, I am a Junior in high school and if I can, I would like to do Independent Study next year based on either the OCW for http://ocw.mit.edu/courses/physics/8-20-introduction-to-special-relativity-january-iap-2005/ or 8.033 - Relativity. I wanted to know if they most likely would be possible for...
  50. R

    What is the energy of photons in pion decay at rest?

    Apologies, this is going to be a bit disjointed, I don't want to write the full question down as I don't want anyone to give me a solution as its an assignment question. 1. am i correct in assuming when a pion decays at rest its energy will be given by: E^2 = p^2 c^2 + m^2 c^4 which...
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