Relativistic Definition and 1000 Threads

  1. K

    A noob asking about relativistic kinetic energy.

    Hey guys, I'm new here. In fact I'm new to the site. Anyway, I just need this question answered. Is it possible to skip the equations for kinetic energy by simply adding gamma to the Newtonian kinetic energy equation? If so, could you give an example?
  2. D

    Relativistic Energy/Momentum of Particles

    Homework Statement A particle with mass M at rest decays into two particles, one with mass m1, and the other with mass m2. Use conservation of energy and momentum to show that: E1 = (M^2 + m1^2 - m2^2)(c^2) ________________________ 2M Homework Equations...
  3. S

    Electrodynamics of point particle at relativistic velocities

    do you know any text or reference with extensive treatment on electromagnetic field ,potential & electromagnetic energy of point particle moving straight at relativistic velocities?
  4. F

    Relativistic Quantum Mechanics

    Hey guys, I am attending my second course in quantum mechanics. At the moment we are studying two-particle-systems using Dirac notation. In our book (An introduction to quantum mechanics - Griffiths) the author wrote that one can prove from relativisitic quantum mechanics that particles with...
  5. W

    Relativistic inelastic collisions?

    Hello. I am trying to better understand relativistic inelastic collisions for objects with mass and the setup for them. Let's say that I have two objects with different masses, one of which collides with the other, which is stationary. Without even specifying a reference frame, can I solve...
  6. M

    Relativistic effects at small temperatures

    Hi all! I'm doing a statistical mechanics class this semester where very often questions like "consider the limit of temperature going to..." pop up. Now, if you consider a relativistic system (say some gas), to what extent does it make sense to talk about temperature going to 0? [to me...
  7. J

    A study of the motion of a relativistic continuous medium

    A study of the motion of a relativistic continuous medium http://www.springerlink.com/content/j8kr55831h411365/
  8. SamRoss

    Derivation of Energy-Momentum Relation WITHOUT using relativistic mass?

    Does anyone know of a derivation of the energy-momentum relation that does not make use of relativistic mass? In other words, a derivation that only uses invariant mass.
  9. soothsayer

    Deriving Relativistic Momentum

    I'm having some problems trying to figure out how to derive relativistic momentum. The way it was explained to me, classically, p=mv=m(dx/dt),but dx/dt is measured differently in different reference frames. So, if you look at time dilation, t=ɣt' where ɣ= 1/(1-(v/c)^2)^1/2 and t' is time in the...
  10. S

    Relativistic Trains in Two Dimensions

    Homework Statement A and B are trains on perpendicular tracks, radiating from the origin of a coordinate system S. Train A is moving along the positive Y axis at a velocity of 0.8c, and train B is moving along the positive X axis also at a velocity of 0.8c. All velocites are measures with...
  11. Mentallic

    Is Flat-Earth's Gravity Theory Flawed Due to Relativistic Acceleration?

    I just recently heard about how this small but still existent flat-Earth society believe that gravity on our supposedly flat Earth is caused by the Earth always moving upward at a constant velocity. Now obviously assuming the Earth is flat and that gravity isn't caused by mass attraction, then...
  12. M

    How Did the Author Derive the Relativistic Mass Formula?

    Homework Statement i was looking through an undergrad's original research and i wanted to get how he derived w\some formula, the paper is "Relativistic dynamics without conservation laws,B. Rothenstein1, Ş. Popescu2" since its open access here is the page with the paper...
  13. M

    Small Conceptual Relativistic Energy Question

    Hi, I have an assignment due in the morning, and it is complete, there is just one tiny thing I am unsure of: In a rest frame, a mass m moves west at speed v, and another mass also m moves east at speed v. Now consider the setup as viewed by an observer going west at speed u. I had to find the...
  14. B

    Reduce relativistic KE threshold to a nonrelativistic form.

    Homework Statement Show that equation 14.13 reduces to equation 13.14 in the nonrelativistic limit. Homework Equations (14.13) K_{th} = -Q \frac{m_1 + m_2 + m_3 + ...}{2m_2} (13.14) K_{th} = -Q ( 1 + \frac{m(x)}{M(X)} ) The Attempt at a Solution For equation 13.14 m(x) is the...
  15. G

    Contradiction in Relativistic Simultaneity in Taylor-Wheeler Spacetime Physics?

    In figure 3-1 (page 63) of Taylor and Wheeler's Spacetime Physics, the observer on the train determines that the lightning strikes are not simultaneous because the flashes do not reach her simultaneously. I see two problems with this. 1. The narrative in figure 3-1 contradicts the text in...
  16. R

    Solving an ODE Related to Relativistic Mass Change

    Homework Statement \frac{dp}{dt} = \frac{d}{dt}\frac{mv}{\sqrt{1-\frac{v^2}{c^2}}} = F Find v(t) show that v -> c as t -> infinity & find the distance traveled in time t if the object starts from rest. Homework Equations The Attempt at a Solution Ive tried rearranging it into either a...
  17. SamRoss

    Is relativistic mass not an appropriate concept?

    Is relativistic mass not an appropriate concept?
  18. maverick_starstrider

    Relativistic Mass and Electrons vs. Muons

    Hi, I can't say I've really ever done much relativity but this made me wonder. Imagine we have some frame where a muon and an electron are interacting where the electron's energy is so high that its relativistic mass can be said to be HIGHER than that of the muon in the same frame. I...
  19. LarryS

    Is QM Phase Inherently Relativistic?

    The phase of a pure momentum state for a single particle traveling freely is (p.r – Et) / h-bar. This also happens to be the Minkowski space-time dot product of the 4-momentum and the space-time 4-vector (relativistic action). Is that just a coincidence or is phase inherently...
  20. C

    Solving for velocity from relativistic momentum

    Homework Statement I need help rearranging the relativistic momentum equation in terms of velocity. Homework Equations p = (mv)/sqrt(1-((v^2)/(c^2))) The Attempt at a Solution p = (mv)/sqrt(1-((v^2)/(c^2))) p(sqrt(1-((v^2)/(c^2)))) = mv sqrt(1-((v^2)/(c^2))) = mv/p...
  21. U

    What is the equation for finding the energy of a photon in a Σ0 decay?

    Homework Statement The sigma Baryon Σ0 is at rest and decays to form an Λ0 and a ɣ photon. Homework Equations Mass of Σ0 is 1193 MeV/c^2 Mass of Λ0 is 1116 MeV/C^2 The Attempt at a Solution K obviously since the Σ0 is at rest, momentum must be conserved and the Λ0 and ɣ go...
  22. C

    Relativistic momentum is 1% greater than classical, at what speed?

    Homework Statement How fast must a body be traveling if its forrect relativistic momentum is 1% greater than the classical momentum Homework Equations P_r = mv/sqrt(1-(v^2/c^2)) P_nr = mv p_r = 1.01P_nr The Attempt at a Solution mv/sqrt(1-(v^2/c^2)) = 1.01mv mv =...
  23. Y

    Relativistic collision and conservation

    Hey, I'm pretty confused by this relativistic collision problem. A particle of mass m moving along the x-axis collides elastically with a 2nd particle of identical mass at rest in the lab frame and scatters. Its final momentum makes an angle theta with the x-axis in the lab. If its initial...
  24. S

    Relativistic mass and Hubble constant

    Student here, please forgive... I have a question about relativistic mass in galaxies. Is the mass of far away galaxies affected by expansion of universe? That is: Is mass of a far away galaxy is different for observer there compared to the observer here? Let's say there is a galaxy identical...
  25. Astronuc

    Good (Relativistic) Plasma Physics Textbooks?

    I happened to stumble across these books which seem to give decent backgrounds on the subject. Nuclear Reactions for Astrophysics: Principles, Calculation and Applications of Low-Energy Reactions by Ian J. Thompson and Filomena M. Nunes...
  26. D

    Relativistic elementary particle problem

    Homework Statement We have the decay process: pion --> muon + anti muon neutrion How long does the muon travel before it decays? (the pion is stationary before the decay) The answer is supposed to be d = c * t (m(pi)^2 + m(mu)^2) / (2 m(pi) * m(mu) ) where t is the mean lifetime of the...
  27. kreil

    Are You Struggling to Understand Reference Frames in Relativistic Dynamics?

    I'm having trouble getting all of the relativistic dynamics information straight in my head. In particular, I'm having trouble with reference frames. It seems that when I am trying to solve problems, even simple ones, I am struggling with what each observer in the different frames should be...
  28. B

    Speed of light Described by relativistic mechanics

    I have been doing research lately. And I wanted to know if anyone could tell me what exactly in relativistic mechanics makes us not able to achieve the speed of light?
  29. B

    Relativistic momentum and energy

    Homework Statement A gamma ray photon with wavelength=2.0 * 10^-15m is traveling in the positive x direction undergoes a one dimensional collision with a stationary proton. a.) find the relativistic momentum and energy of the photon and proton before the collision. b.) assuming the...
  30. S

    Conceptual help with relativistic transformations for the energy of light waves

    I'm in a math class reading Einstein's original paper "On the Electrodynamics of Moving Bodies," from 1905. I'm stuck in Section 8, "transformation of the energy of light rays." We're basically trying to show that that Placnk's constant is Lorentz invariant- if anyone has an easy way of...
  31. kreil

    How Does the Relativistic Doppler Effect Apply on a Rotating Disk?

    Homework Statement A source and detector are placed a certain angle \phi apart on the edge of a rotating disk. The source emits radiation in all directions at a frequency \omega_* in its instantaneous rest frame. What frequency is the radiation detected at? (Hint: Little information is...
  32. P

    Law conservation of charge relativistic

    \frac{\partial \rho}{\partial t}+div\vec{j}=0 In Deckart coordinate system \frac{\partial j_x}{\partial x}+\frac{\partial j_y}{\partial _y}+\frac{\partial j_z}{\partial _z}+\frac{\partial (c\rho)}{\partial (ct)}=0 definition divA^{\mu}=\frac{\partial A^{\mu}}{\partial x^{\mu}} scalar...
  33. P

    Electromagnetic waves relativistic

    If we have case \rho=0, \vec{j}=\vec{0} then we have this equations \Delta\vec{E}-\frac{1}{c^2}\frac{\partial^2 \vec{E}}{\partial t^2} \Delta\vec{B}-\frac{1}{c^2}\frac{\partial^2 \vec{B}}{\partial t^2} Particular solutions of this equation \vec{E}=\vec{E}_0...
  34. kreil

    Constant Acceleration in Relativistic Mechanics

    Homework Statement Assume a particle moves along the x-axis. It is uniformly accelerated, in the sense that the acceleration measured in its instantaneous rest frame is always g, a constant. Find x and t as functions of the proper time tau if the particle is at x0 at t=0 with no velocity. The...
  35. M

    How Much Energy is Converted from Mass to Kinetic Energy in Uranium Fission?

    Homework Statement In a fission process, a slow neutron causes a uranium nucleus (m=218943.42 MeV/c^2) to split into a barium nucleus (m=131261.73) and a krypton nucleus (m=85619.32), plus two excess neutrons (actually 3 including the original neutron, but that is present before the process as...
  36. B

    Does light slow down (relativistic) near a black hole?

    Does photons actually slow down near a black hole? Whenever I look up these info, I always read the mention of red shifting. The problem is we don't have a detector that is immune from the effects of relativity to directly observe these events in real time. However, does current...
  37. A

    Relativistic Inelastic Collision of Protons

    Homework Statement Let us consider a perfectly inelastic collision between two protons: an incident proton with mass m, kinetic energy K, and momentum magnitude p joins with an originally stationary target proton to form a single product particle of mass M. Due to conservation of momentum...
  38. kreil

    Can Relativistic Velocity Addition Ensure Speeds Stay Within Limits?

    Homework Statement Show that the addition of velocities implies the following: - If | \vec V | < c in one inertial frame, then | \vec V | < c in any inertial frame - If | \vec V | > c in one inertial frame, then | \vec V | > c in any inertial frameHomework Equations V^{x'}=\frac{V^x...
  39. S

    Why Do Relativistic Signals Differ Between Observers?

    I was solving this problem, and I was comparing my answers with a classmate, and we got very different answers. I don't think I made a mistake here, but I may have missed something. Homework Statement Tipler - Modern Physics 5e 1-57. "Two observers agree to test time dilation. They use...
  40. A

    Does Relativistic Kinetic Energy Increase with Velocity?

    So, there is a sentence in my book, along with a graph, stating that "relativistic kinetic energy becomes infinite as v approaches c." But then in a concept problem, it says "A proton is accelerated from rest by a constant force that always points in the direction of the particle's motion...
  41. P

    Bike Moving at 0.866c: Length, Time & Turns Explained

    If a bike is running at v=0.866c, and it travels path of length L in time T, when observed from the stationary frame, same path will have length L/2 and be traveled in time T/2 in his, moving frame (because gamma=2 for v=0.866c). Now, what I don't understand is: If the bike is not...
  42. X

    Solving a Relativistic Ideal Gas Momentum Probability Distribution

    Homework Statement For a relativistic ideal gas, the momentum probability distribution is given by where http://latex.codecogs.com/gif.latex?\epsilon_p=\sqrt[]{m^2c^4+c^2p^2}. Determine A Homework Equations The Attempt at a Solution I know that...
  43. A

    Relativistic mass affect weight of an object?

    For example, a top spinning near the speed of light, would the relativistic mass be affected by gravity and therefore increase the weight of the object? If it does, then are the highest speeds which we could realistically get it to spin at it not even close to the speed of light, making any...
  44. V

    Physics Relativity Question-Train at Relativistic Speeds

    Homework Statement Train Direction----------> ------------------------------------------------------------------------------------- Andy Train...
  45. A

    Relativistic kinetic energy comapred to Newtonian

    Homework Statement Find the speed of a particle whose relativistic kinetic energy is 40% greater than the Newtonian value for the same speed. Krel = relativistic kinetic energy Knew = Newtonian kinetic energy Homework Equations Krel = (gamma - 1)mc^2 Knew = 0.5mv^2 gamma =...
  46. A

    Planck relation, relativistic doppler effect, and relativistic mass

    I've been trying to graph an idea I had, but frankly I don't understand SR well enough to ensure my assumptions are correct, and that I'm using the correct formulas. I would appreciate any input/corrections you folks could give. Here's the idea, which I'll follow with my assumptions: Idea...
  47. D

    Compton scattering in relativistic flow

    For reference: http://arxiv.org/abs/astro-ph/9912312" The paper linked above notes in the introduction: The authors are performing this calculation for an isotropic electron distribution. However, for my work, I am considering an electron population with a relativistic macroscopic bulk...
  48. B

    General equation for relativistic momentum

    Homework Statement What is the most general mathematical form for the relativistic momentum which will prevent the velocity of an object from becoming greater than c, when the object is acted on by a constant force F and the equation of motion is dp/dt=F Homework Equations The...
  49. R

    Relativistic Effects on our Observations of the Universe

    While observing the Sun, which is 8 light-minutes 12 light-seconds away from us. We (by visible and invisible spectrum of the electromagnetic radiation) observe its state 8.20 minutes ago. Special relativity forbids any information to travel at speeds greater than that of light. This should...
  50. fluidistic

    Calculating Relativistic Doppler Shift for Moving Radar

    Homework Statement A car is getting closer to a radar as a speed of 135 km/h. If the radar works at a 2 \times 10 ^{9} Hz, what difference of frequency is observed for the radar?Homework Equations \mu=\frac{\mu _0 \sqrt {1- \frac{v^2}{c^2}}}{1-\frac{v}{c}}The Attempt at a Solution I converted...
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