Relativistic Definition and 1000 Threads

Homework Statement the relativistic momentum of an electron is 1.6 times larger than the value computed non-relativistically. What is the speed of the electron. Homework Equations Relativistic momentum p=mv/√1-v2/c2 The Attempt at a Solution Moving most of the equation around is fairly easy...

How is E=mc^2 derived from relativistic doppler effect? I looked up on wikipedia but it seems to have some errors. https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence#Alternative_version

Homework Statement We now specify the velocity v to be along the positive x1-direction in S and of magnitude v. We also consider a frame \overline{S} which moves at speed u with respect to S in the positive x1-direction. question 1 : Write down the transformation law for p^\mu . question 2...

I’m trying to get a better handle on reconciling the concept of time as it relates to the quantum wave function and the relativistic 4-momentum. To put it simply, do we look at the coefficient of the time variable in each as something separate from the time variable itself, or do we treat these...

I came up with this problem, which is non-trivial at least for me: Train accelerates with constant proper acceleration. When the speed of the train relative to rails is zero, rails feel the train exerting 1000N force on the rails. What force do rails feel the train exerting on the rails when...

Homework Statement Consider an electron with spin ##\vec{S}## and magnetic moment ##\vec{\mu}=-\frac{e}{m}\vec{S}##. It is moving with the velocity ##\vec{v}(t)## relative to the inertial frame of reference ##I## through the electric field ##\vec{E}##. Calculate the angular momentum the...

Is there any good information about the chemical composition of relativistic jets from neutron stars? If the chemical composition of the jets was different from the accretion material it could shed light on the process that forms the jets.

Homework Statement A particle of mass m ha speed 0.546c relative to inertial frame S. The particle collides with an identical particle at rest in the inertial frame S. Relative to S and in terms of c, what is the speed of S' in which the total momentum of these particles is 0. Homework...

Homework Statement Hi- I've been doing some questions and came across the following A high energy particle, traveling towards an observer with velocity v decays to produce a photon with energy E in the rest frame of the particle. Find the frequency at which this photon would be detected by...

A car has wheels with exactly 1m of circumference and travels at constant relativistic speed with ##\gamma = 2## in an horizontal rectilinear road between two points A and B marked on the road itself and separated from a distance of 8 m, as measured from a frame of refence which is still with...

Hello everyone, I know that the photon has zero rest mass and I know that otherwise the relativistic mass formula would not make sense. When I searched for an answer to the question "how can a particle have zero mass and still possesses energy if E=mc^2" I got an answer saying the mass energy...

I've been working on my SR book http://www.lightandmatter.com/sr/ and its presentation of a suite of related mathematical tools such as the Levi-Civita tensor. This is aimed at the upper-division undergraduate level, although there are optional sections at the end of some of the chapters that go...

I am interested on the earliest reference on the deprecation of the concept of relativistic mass. AFAIR even Einstein used relativistic mass and the somehow related concepts of transversal and longitudinal force. I am trying to find a long lost article about showing all these concepts related...

[mentor's note - lightly edited to fix the Latex] Hi there, I was hoping if someone could clear my small misconception for this equation. f' = f \left( \frac{ 1- \beta }{ 1+\beta } \right)^2 I had thought if the numerator is negative and denominator is positive that means the signal of light...

Before continuing, I wanted to verify I have fixed the issue with the wording of my variables, and, I have seen answers for this question elsewhere. I also know I'll get full marks regardless of how I use my equations, as this question obviously isn't very focused on that, however, for my own...

Hi, I'm really curious about this one. :) Let's imagine a massive, large object with a very low albedo traveling at a slightly sub-c speed enters the solar system and passes through it before leaving on the opposite side. Please, would us earthlings detect it as it approaches, passes by and...

Hi. I am working through a QFT book and it gives the relativistic Lagrangian for a free particle as L = -mc2/γ. This doesn't seem consistent with the classical equation L = T - V as it gives a negative kinetic energy ? If L = T - V doesn't apply relativistically then why does the Hamiltonian H =...

I just wanted to check that I am thinking about the coordinate transition correctly. The relativistic generalization of Euler's equation is (from Landau & Lifshitz vol. 6) ## hu^\nu \frac{\partial u_\mu}{\partial x^\nu} - \frac{\partial P}{\partial x^\mu} + u_\mu u^\nu \frac{\partial...

Dear all, Let's assume I was planning an interstellar journey with relativistic speed. Being at rest on earth, the distance to the destination is ##d##. Let's further denote the proper time I will need to reach the destination as ##\tau##. Is there an official term for the effective speed...

Hello, If I have a momenta pμ=(E,px,py,pz) and transform it via lorentz boost in x-direction with velocity v I'll get for the new 0th component E′=γE+γvpx why is this in the limit of low velocities the same as transforming the energy by a galilei transformation with velocity v? For γvpx i get...

A particle with mass M a rest decays into two particles a and b. I know that Ea + Eb = Mc2, from conservation of energy. But I'm pretty confused about signs in the conservation of momentum equation, and I've actually seen two versions! pa + pb = 0, so pa = - pb. But I've also seen pa = pb! I...

Homework Statement A body at rest in a frame of reference S disintegrates into two pieces moving in opposite directions. The masses of each fragment are 3.0kg and 4.0kg and their velocities 0.8c and 0.6c, respectively. Find the mass of the body before it disintegrated. (Answer: 10kg) Homework...

Homework Statement At what energy will a non-relativistic calculation of the De Broglie wavelength of an electron be in error by 5%? What is this energy for a proton? Comment on your results. Homework Equations I have two (seemed to be) logical answers for this question, but with different...

Homework Statement What is the lagrangian of a free reletavistic particle in a electro-magnetic field? And what are the v(t) equations that come from the Euler-Lagrange equations (given A(x) = B0/2 crosProduct x) (B/2 is at z direction) Homework EquationsThe Attempt at a Solution I've got to: L...

Homework Statement Two asteroids are approaching one another moving with the same speed speed as measured from a stationary observer on Europa. Their relative speed is 0.5c. Find the speed of one of asteroids relative to Europa. I understand how relativistic velocity addition works but am not...

Homework Statement The instantaneous force F acting on a particle, as measured in frame S, is Use the formula for the linear momentum () in and the definition of the acceleration a to show that The Attempt at a Solution The professor said that this required use of programs such...

Hi, I am looking for textbooks in relativistic quantum mechanics and group theory. I have just finished my undergraduate studies in Physics and am looking to specialise in theoretical high-energy physics. Therefore, textbooks in relativistic quantum mechanics and group theory suited for that...

This is a new one one me: http://www.iflscience.com/physics/4-examples-relativity-everyday-life

SO(3) is subgroup of Poicare group.Does Relativistic Quantum Mechanics obey rotational symmetry.If it is,why we do not still keep the non-relativistic concept of angular momentum(orbit angular momentum plus spin) for relativistic concept of angular momentum,but we instead replace the concept by...

Homework Statement They were going to purchase an electron microscope, and wanted the electrons velocity to be as high as 25% of the speed of light after acceleration. There was a microscope at hand that had an accelerating voltage of 40 kV. a) How large is the electrons relativistic mass when...

Homework Statement Good morning-afternoon. I have been tasked with solving the next exercice; but I am unable to spot the error. Please can anyone point me in the right direction?A)Calculate the thresold energy of a photon to disintegrate in an electron and a positron in the presence of an...

Homework Statement Two rockets leave their space station along perpendicular paths, as measured by a flight controller on the space station (see figure). The flight controller records the speeds of Rockets 1 and 2 to be 0.6 c and 0.8 c respectively. What is the velocity of Rocket 2 as measured...

Homework Statement Hi everybody, I was studyng a photon disintegrating in one electron and one positron in the presence of a heavy atomic core; I want to find the final momentum of the atomic core Homework Equations Conservation of energy: Eγ=2me+Sqrt(Mn2+Pn2) Conservation of momentum Pγ=Pn...

Homework Statement Write the invariant s = (P1+P2)2 as a function of masses amd energies of the process 1+2 → 3+4 in the center of momentum frame and on the lab frame, in which b is at rest. Interpret the result. Homework EquationsThe Attempt at a Solution For the CoM frame I have: s =...

From the semi-classical Bohr model of the hydrogen atom the velocity of the electron in a certain orbit can be determined. With these velocities the electron's relativistic masses can be determined. With E=mc2 the energy levels are in agreement with those from the Bohr model. I know Bohr's model...

Hello everyone! I would like you to recommend me a book for relativistic quantum mechanics. It's for an undergraduated class. thanks

I just read this article: http://abcnews.go.com/Technology/plutos-majestic-mountains-atmospheric-haze-revealed-photo-horizons/story?id=33832751 The article itself is really cool, but something at the bottom of it caught my attention. I don't know how fast New Horizons is traveling, but say...

My name is Bob. I'm floating in deep space and I have these two powerful cannons that shoot my friends Alice and Charlie in opposite directions to me, one to the left and one to the right. I shoot each out at 0.9c. As I look to the left, I see that Alice is flying away from me at 0.9c. Then...

Homework Statement [/B] A low flying Earth satellite travels at about 8000m/s. For the satellite, the relativistic factor $$\gamma = \frac{1}{\sqrt{1-\beta^2}}$$ where $$\beta = \frac{v}{c}$$ is close to 1 because v<<c. Estimate by how much gamma actually deviates from 1 by expanding gamma in...

Hey! I wanted to prove that: $$ P_L \bar{ \psi } = \bar{ \psi } P_R $$ And I want to know if I did it correctly. $$ --- $$ Here is what I did: $$ P_L \bar{ \psi } = \frac{ ( 1 - \gamma_5 ) }{2} \psi^{ \dagger } \gamma_0, $$ $$ = \frac{ 1 }{2} \psi^{ \dagger } \gamma_0 - \frac{ 1 }{2} \gamma_5...

Hey! I was working with Dirac's equation: $$ ( i \hbar \gamma^\mu \partial_\mu - m ) \psi = 0, $$ and I found that if you work with a function that depends on the momentum, $$ \psi ( \mathbf{p} ), $$ you obtain: $$ ( i \gamma \cdot \mathbf{p} + m ) \psi ( \mathbf{p} ) = 0. $$ The problem is...

Here is a problem: Imagine two equally charged capacitor plates parallel to the x-y axis, whose area is large enough compared to the distance between them that fringe effects can be ignored. The bottom plate (at z=0) is + charged, and the top is - charged. The vector field E is therefore...

Picture a large ring floating in space. It is rotating with angular momentum L. However, its radius is so large that it has essentially no tangential velocity or momentum and therefore no kinetic energy. The total energy is mc^2, with m being the invariant mass. It then begins to draw itself...

Then why did they find out it's harder to accelerate particles when they are near the speed of light? Even the lorentz equation indicates that the dimension is mass (rest mass / lorentz factor). Infinite energy is required to accelerate an object approaching to the speed of light, but what did...

bcrowell submitted a new PF Insights post Relativistic Work-Kinetic Energy Theorem Continue reading the Original PF Insights Post.

I have a quick question about the Special Relativity. Non-relativistically, we expect no doppler shift in the wavelength of the emitted light if the source is moving at right angles to the line of sight to the observer. However there is a transverse doppler shift even in this case, caused by...

I would like people's opinions on why the negative energy solutions of Dirac's Relativistic Wave equation were simply ignored in 1934 to make things fit. Another related question is with the energy conservation laws as they stand. Why in pair production from a photon at 1.022MeV forming a...

Orodruin submitted a new PF Insights post What is relativistic mass and why it is not used much? Continue reading the Original PF Insights Post.

This question and answer are posed in Kim Stanley Robinson's novel "2312". My question is, is this all made up? Or might it be accurate?

I'm aware that most modern textbooks gloss over relativistic qm and jump to qft. Since I'm not that brilliant of a student I'm thinking that i should firstly familiarize myself with relativistic and then go to qft. So my first question: Is it worth it to study relativistic qm or should i jump...