Relativistic Definition and 1000 Threads

Homework Statement This is just a short response problem on my homework. It asks: "If a particle is moving at a relativistic velocity, is the following equation still valid? |q|vB = mv2/r If the particle is an electron, what is the value of the mass?" (electron mass = 9.1094x10-31)...

Relativistic length expansion in general accelerated system revisited Authors: J.Foukzon, S.A.Podosenov, A.A.Potapov (Submitted on 13 Oct 2009) http://arxiv.org/abs/0910.2298 Abstract: The aim of the present article is to give an exact and correct representation of the essentially...

If a spaceship is moving at a relativistic speed past the earth, the people on Earth would believe that the time in the spaceship was moving slower. The people on the spaceship would believe the time on the Earth was moving slower. So what happens when the spaceship stops? Do both times revert...

Homework Statement A meson (elementary particle) decays into two photons, each of energy 150MeV in its rest frame. Find the mesonic kinetic energy in the case of a symmetric decay in flight with an angle of 60degrees between the photon momenta (30 degrees for each particle on each side of the...

Just wondering here, how much energy (in Joules or Mtons) would an asteroid say 15 km wide have if it impacted the moon at 99.9% the speed of light? btw, I'm trying to figure this calculation out in terms of SR where the mass of the asteroid would appear much greater than if it was traveling...

Is a phenomenon which is periodic in a frame A of reference also periodic in another frame B moving at a constant speed v with respect to A ? I think general relativity will answer this in the negative. How about special relativity? Consider a world line in A with...

I'm interested in the following action for a relativistic point particle of mass m: S = \int d\tau (e^{-1}\dot{x}^2 - em^2) where e = e(\tau) is an einbein along the particle's world-line. If we reparametrize the world-line according to \tau \to \overline{\tau}(\tau) = \tau + \xi(\tau)...

Homework Statement Unstable, subatomic particles called muons have a rest energy of 105.7 MeV and a speed of 0.994c. If a muon were to decay and produce an electron and a photon, what would be the momentum of the electron as measured by an observer in the muon's frame? HINT: assume that the...

Homework Statement Suppose rocket traveler Amelia has a clock made on Earth. She flies to and back from a planet 12 light-years away (as measured from rest with respect to Earth) from Earth at a speed of 0.6c. Every year she sends a signal to Earth. How many signals does Earth receive by...

Homework Statement A stick of proper length L moves at a speed v in the direction of its length. It passes over a thin sheet with a hole of diameter L cut into it. As the stick passes over the sheet is raised and the stick moves through the hole so that it is underneath the sheet. Is this...

Homework Statement a) We have an incident photon beam into a fog chamber, and we observe a compton electron with a moment of 1,5 Mev/c emitted in a 10º angle to the incident beam. ¿Which is the energy of the incident and scattered photons? b) Find the minimum energy that should have the...

Dear users, I wonder if there is anybody who can give me a hint on how to handle the following situation: In the 2+1 dimensional Klein-Gordon equation with coordinates (t,x,y), I use as initial condition for \Psi(x,0) a spherically symmetric Gaussian. The relativistic dispersion relation...

Homework Statement "A photon of energy E collides with an electron at rest. Calculate the maximum amount of Energy Ek that may be transferred to the electron. Make a graph of Ek versus E, labeling the scale in electronvolts. Homework Equations Transfer = Ek = E - mc^2*E/(mc^2 + 2E)...

Let's say i am in a car traveling at 0.5c relative to a truck- which is at rest relative to the ground- approaching me from the opposite direction. Relative to me, the truck is going at 0.5c. Both, truck and car, frames of references are inertial frames of reference. Therefore, the principle of...

I have a relatively simple problem that I'm having trouble with. A ship is going at 0.90 c, over a distance of 80 light years. In my text the method for determining the time spent traveling is: 80 years + (0.1 * 80) = 88 years This method seems logical, at 0.9 of the speed of light this...

"high school" algebra -> relativistic conservation of momentum and energy Homework Statement Consider a head-on, elastic collision between a massless photon (momentum po and energy Eo) and a stationary free electron. (a) Assuming that the photon bounces directly back with momentum p (in the...

[b]1. A lambda particle decays into a proton and pion and it is observed that the proton is left at rest. a. what is the energy of the pion? b. what is the energy of the original lambda? m of lambda = 1116MeV/c^2, m of proton = 938 MeV/c^2, and m of pion = 140 MeV/c^2 Homework...

Homework Statement Nevermind, got it. Two spaceships approach the Earth from opposite directions. According to an observer on the Earth, ship A is moving at a speed of 0.753c and ship B at a speed of 0.851c. What is the speed of ship A as observed from ship B? Of ship B as observed from ship...

Homework Statement A stationary particle of rest mass 2m_{0} is hit by a particle of rest mass m_{0} and kinetic energy 2m_{0} c^{2}. I must find the rest mass of the composite particle afterward.Homework Equations Conservation of momentum and energy. The Attempt at a Solution I worked...

Hi! Well, I have a problem, I'm writing Extended Project For Applied Science about Death of the Universe, I am stuck. I am really desperate so I decided to put it on forum. First: The Universe is accelerating so, according to Lorentz's Factor, its mass should be increasing m = \gamma m_{0} =...

Hi- I have a question regarding relativistic kinetic energy. If a spaceship is moving at a velocity relative to the Earth and then accelerates, to compute the work done by the engine/KE, should I use the given final velocity(the problem isn't entirely clear what this speed is in reference to)...

Homework Statement http://picasaweb.google.com/RBWang1225/DropBox?pli=1&gsessionid=ZEGTyKIL2-jRa6hnTPGfxg#5432828568883584962 http://picasaweb.google.com/RBWang1225/TheClassicalTheoryOfFileds#5432828592785160466 Homework Equations...

Homework Statement Using the technique of Taylor expansion, find an approximate expression for the relativistic factor γ for small v (i.e., expanded around v = 0) that is correct to order v2. Homework Equations γ=1/SQRT(1+ V2/C2). But in class, my professor just substituted X=V/C, so...

SOLVED (Problem 10, Chapter 2, Modern Physics - Serway) Homework Statement Recall that the magnetic force on a charge q moving with velocity \vec{v} in a magnetic field \vec{B} is equal to q\vec{v}\times\vec{B}. If a charged particle moves in a circular orbit with a fixed speed v in the...

Hi, I'm currently writing a paper on Relativity, which mostly uses original papers of Einstein. For this reason, I have little idea what the ultimate fallout of all his upheaval is. I am aware that electromagnetic fields become "shadows" of the complex mathematical entity called the...

This isn't really so much of a homework problem, but I'm reading this webpage, and there's one part of the derivation of the required proton KE needed to produce a static antiproton. The part that's puzzling me is "and using... m2inc4 - p2inc2 = m20c4 " I don't see where this formula is...

Hey, I have two separate questions: 1) If one is moving in a car and throws a ball straight up, say out the sun roof, the ball will have zero velocity relative to an observer in the car. Conversely, it will have the velocity of the car to a stationary observer. How does one account for drag...

I'm looking over some common physics equations as a review for the course I'll be taking next semester, and for each equation, I'm coming across two equations for each, a relativistic and a non relativistic. The class I'll be taking will be on mechanics, inertia, etc., so I figure I'll only...

Say we have a real field that satisfies: E^2 = P^2 + m^2 Assume spacetime is 4D. Assume the field is at rest and grab a single point of this field and slowly displace it a distance x. Just as an anchored string (string with an additional sideways restoring force) with fixed end points will...

Homework Statement Given that the trajectory in frame S is: x=\frac{c^2}{a}(\sqrt{1+\frac{a^2t^2}{c^2}}-1) Show that in S' that is moving in the +x direction at speed u: x'=\frac{c^2}{a}\sqrt{1+\frac{a^2(t'-A)^2}{c^2}}-B Find the constants A and B. Homework Equations Lorentz...

Reading the Landau's "The classical theory of fields" (chapter 2, section 9 ) I have some doubts in explaining the steps in derivig the formula for the variation of the action for the relativistic free particle...

This is a thought experiment that my friends and I (physics graduate students all) were pondering while we should have been doing Jackson homework. Consider a boat traveling at relativistic speeds. From the boat's frame, the water is contracted, and therefore is more dense. This would...

Hi! I have the following problem: Example: collision of 2 electrons For non-relativistic scattering it is easy to show that the speed of the CM frame with respect to the lab frame is equal to the speed of the electrons in the CM frame, expoloiting the fact that in the lab frame, one of the...

Given the lifetime of a muon as 2.197 microseconds, and the rest mass of 105.65MeV, and a total particle energy of 10GeV, I need to calculate how far, in the rest frame, the particle will travel before decay.Homework Equations Beta=v/c Gamma=1/sqrt(1-beta^2) deltaT'=gamma*deltaT...

A person is in a confined cubicle - say 1m x 1m x 1m. Assuming he is not accelerating, he should not be able to tell if he is moving with respect to any other non-acclerating coordinate system. Are there any limits on his relative speed?

I have a question regarding the conditions "prior" to the Big Bang. I realize tere is no empirical evidence for these conditions, only speculations. At the point of the Big Bang, all of matter and energy was "infinitely" densely concentrated at a single point, correct? Even though GR breaks...

Have there ever been any attempts to create a theory of gravity within the context of a flat 4-D Minkowski spacetime? Rather than taking the general relativistic route of gravity being a manifestation of curved spacetime geometry, has anyone historically ever attempted to put the more...

In what situations do Newton's law of universal gravity fail to predict correctly how matter moves? The examples I know of are frame dragging (around rotating BH), shifting of light paths, shifting orbits of planets. But does Newton's law really predict the magnitude of gravity accuratly? How...

Homework Statement at what speed does the expression for relativistic kinetic energy vary from the non-relativistic expression by 5%? Homework Equations Relativistic kinetic energy K=(gamma-1)mc^2 Non-relativistic kinetic energy K=0.5mv^2 The Attempt at a Solution I'm not...

I'm trying to solve a problem for a relativistic electron in an external magnetic field with vector potential \vec A using the Lagrangian \mathcal L = -mc^2 / \gamma - e \vec v \cdot \vec A in cylindrical coordinates. But isn't this DREADFULLY TERRIBLE, since when I try to compute...

I know that for normal Newtonian motion, we can write v=rω. Does this hold for relativistic motion as well? My gut tells me no, but I can't find (in my GR book or online) a comparable equation or discussion of relativistic rotation. It should be noted that while the case of relativistic motion...

In J.D. Jackson's Classical Electrodynamics, an argument is made in support of the assertion that the relativistic Lagrangian \mathcal L for a free particle has to be proportional to 1/\gamma. The argument goes something like this: \mathcal L must be independent of position and can therefore...

This is actually a problem in Goldstein. Homework Statement A rocket that ejects stuff at a speed a in its rest frame. Demonstrate that m\frac{d v}{dm} + a\left(1 - {v^2 \over c^2}\right) = 0 in which m is the invariant mass of the rocket and v is the velocity of the rocket viewed in Earth...

To a moderator: this is a theoretical, concept-based question. Say two balls of putty, moving relativistically near the speed of light, collide (although i understand this is not possible theoretically and realistically). They collide at a slight perpendicular displacement, instead of...

Homework Statement My question concerns what happens when one is transforming relativistic velocities in more than one dimension. The Lorentz velocity addition formula is well known. Suppose there is an inertial reference frame F' moving at speed v in the +x direction with respect to a...

Hello my name is Unto I currently study Physics (it's my first year) at the University of Bristol in England. I first came here with a really horrible relativistic kinematics problem, but I got no answers and managed to solve it myself. However you seem like nice guys, and it's always...

Hello everyone! I apologize if my first post is of a problem that may seem like a really silly one. But it was something we were stuck with today in Modern Physics class. It is NOT a homework assignment! We have proved that relativistic force, F = m*(du/dt)*(gamma)3 where gamma is the Lorentz...

Homework Statement Taking into account the electrons momentum and relativistic energy prove that W=(m(sub0)^2c^4+p^2c^2)^(1/2) Homework Equations p=(gamma)m(sub0)v; W=(gamma)m(sub0)c^2. The Attempt at a Solution I have tried expanding the relativistic factor...

This may be a basic question; I'm not sure because I'm just getting into quantum theory. As I understand it, the electron orbits somewhere around the order of n x 10^6 (based on calculations I've seen). Moreover, the wave model of the electron suggests that it moves at velocity c. From this...

OK, here is an interesting assertion I haven't seen before. Thought I would see what some of the folks here think. The paper is: Quantum Preferred Frame: Does It Really Exist? by J. Rembielinski, K. A. Smolinski (2009) Abstract: "The idea of the preferred frame as a remedy for...