Relativistic Definition and 1000 Threads

I'm looking for an intuitive explanation for the redshift and blueshift phenonema that occurs when a light ray is emitted transversely. According to wikipedia: Assuming the objects are not accelerated, light emitted when the objects are closest together will be received some time later...

This question has came up to my mind and I think it really isn't easy as it sounds. In Newtonian physics we could use the Earth as the basic frame and compare velocities of cars, planes etc. on our planet. But in relativistic physics, things get complicated because, as we are in a...

Hello! I'm currently going through The Classical Theory of Fields - Landau, Lifshitz and I needed a bit of help on some of the math going on in a certain section. The book can be found here https://archive.org/details/TheClassicalTheoryOfFields On page 27, they give the action as...

1. How do we know that objects mass increase as they approach the speed of light 2. How did whoever figured this out do so

Homework Statement A spaceship travels from Earth to a star that is 6 light years away. The spaceship takes 2.5 years to reach the star in its frame. Calculate the velocity of the spaceship. Homework Equations x=\frac{x_0}{γ}, t=γt_0 The Attempt at a Solution I guess I have to...

Hello! First, please, zoom in the attached file and take a look on it. Image 1 demonstrates the situation: two identical balls collide, horizontal component of velocity of both remains unchanged and vertical component becomes opposite as a result of the collision. Table in image 3 shows all...

Whilst reading following a derivation of the Relativistic Energy equation I came across the following: d/dt[mu/(1-u2/c2)1/2] = [m/(1-u2/c2)3/2] du/dt. I was wondering how that step was done.

For hydrogen atoms, all book take correction up to 1/c^2 where the perturbation is -P^4/8*m^3*c^2. And they go solving it by sandwiching p^4 term where they consider p^2 = 2m*(1+e^2/r). and they square it to solve for p^4. To get a better view of perturbation to first order please see...

Let's say there's a current going around in a superconducting loop in vacuum. Then the loop gets buried in huge amount of matter, which has the same magnetic susceptibility as vacuum. (when not affected by gravity the matter has the same magnetic susceptibility as vacuum) Will the magnetic...

Homework Statement What is the minimum proton energy needed in an accelerator to produce antiprotons by the reaction: P+P \rightarrow P+P+P+\bar{P} The mass of both protons and antiprotons is m_p. Assume first that the initial protons have equal energy (the lab frame is the...

I have spent some time reading other threads and other source. However I could not find any clear derivation of relativistic mass and momentum In this case for example http://www.phys.ufl.edu/~acosta/phy2061/lectures/Relativity4.pdf On the first page, how come you can give such a new...

It was hard to decide where to post this. I want it to be in the right section (maybe textbook discussion or academic guidance) but I also want people that would know the answer to see it. Mods can move it if needed. I'm looking for something to read other than Merzbacher chapter 24. I just...

Hello all, I have just covered a very brief module on special relativity as a part of my physics course. I have also done some extra reading mostly; Morrin's Classical Mechanics. While I found the book really illuminating in some aspects, I still feel that regardless of how hard I try there is...

Homework Statement You are driving down a two-lane highway and a truck in the opposite lane travels toward you. Suppose the speed of light in a vacuum is 65 m/s. Determine the speed of the truck relative to you when a - your speed is 25 m/s and the truck's speed is 35 m/s and b - your...

Suppose you were to board a ship on Earth departing for a star system 1,000 light years away. You accelerate at 1g for the first 500ly, then decelerate at 1g for the second 500ly. Observer on Earth will claim 1,001.936 have passed during your voyage, whereas you will have experienced 13.452...

Homework Statement In Minkowski spacetime, two observers, A and B, are moving at uniform speeds u and v, respectively, along different trajectories, each parallel to the y-axis of some inertial frame S. Observer A emits a photon with frequency nu_A that travels in the x-direction in S and is...

If a particle of mass M is at rest in a lab when it decays into 3 identical particles of mass m with: particle 1: having a velocity of 4c/5 in the -i direction vector particle 2: having a velocity of 3c/5 in the -j direction vector particle 3: having an unknown velocity in a direction defined...

Homework Statement At what energy does an electron become “relativistic”? Consider electrons with kinetic energies of 50 eV, 50 keV, and 50 MeV. For each case, calculate the momentum of the electron first using the non-relativistic formula for kinetic energy, and then using the correct...

I know the reasons why the relativistic mass equation (M= gamma Mo) is out of favour with what seems to be a majority of theoretical physicists but I am unsure about one particular thing: Suppose we knew the mass and velocity of a relativistic particle and wanted to calculate its KE. Isn't...

Today, all of the scientific world (including /r/physics) buzzes about BICEP2's discovery of gravitational waves dating from Big Bang as an undispute confirmation of the general relativity. Now I wonder is it really GR? Can't it be explained by simple Newton's mechanics? I mean if you can...

Relativistic compressor "paradox" Let's say we have a metro tunnel that is a circular loop with 1 m x 1 m rectangular cross section. The tunnel is 100 m long. There's a 50 m long train in the tunnel, the train fits snuggly in the tunnel. And there's air in the tunnel, at 1 atm pressure, and...

Let's say we have a long cylinder and two pistons inside the cylinder, and some vapour between the pistons. Now we make the pistons accelerate with some coordinate acceleration, along the cylinder axis, same coordinate acceleration for both pistons. Cylinder is static. Going to the frame of...

Homework Statement A particle of mass m and kinetic energy K strikes and combines with a stationary particle of mass 2m, producing a single composite particle of mass √17 m. Find the value of K Homework Equations E= γmc^2 , p = λmv The Attempt at a Solution I have tried many times...

Homework Statement The example below illustrates the relativistic phenomenon that synchronicity of events is not absolute but it depends on the reference frames. Spaceships A and B, while moving away from each other with a constant speed of v = 0.553c, are watching a competition between...

Just a thought... Say that a stationary (relative to me) source of light emits a photon with the energy level (as observed by me) appropriate to pair produce an electron-positron pair. Meanwhile, a second observer travels towards the light source, thus blue-shifting the light, and hence...

Hi everyone, first post here. Lurking for a while but it was time to register.. I'm trying to conceptualize an idea in which humans are sent to orbit a very massive object, like a neutron star, a magnetar or even possibly a black hole. I would like the ship to be relatively close to the surface...

My textbook says ψ(x,t)=exp(i(p_{0}x^{0} + p^{→}\cdotx^{→})/h)=exp(i*p\cdotx/h) (note that by h I mean 'h-bar'...couldn't find the symbol). I don't recognize (like my text implies I should) how the first equation equals the second. Where did the p_{0}x^{0} go? Sorry for my stupidity here. Any...

Guys, My calculus is really rusty and I need help solving this equation using a time derivative (denoted with a dot) in order to get the relativistic equation of motion for the Universe The equation is: adot^2 = Λc^2a^2/3 where adot is the time derivative of the scale factor, lambda...

Hey guys, I regard a relativistic vector: $$ k^\mu =(k^0,k^1,k^2,k^3,)=(\frac{\omega_k}{c}, \vec{k} ) $$ What is |\vec{k}| of this vector? Is it the same as k^0? THX

Homework Statement I proved that a relativistic 1D force is F = \gamma3*m*dVx/dt = m * dVx/dt * 1/ (1 - (v/c)2)3/2 Then, "This is a separable differential equation that can be solved using a trig substitution. Use this (or some other technique that works) to show that the velocity is given...

[I could not fit the last "e" into the title] Hi! I am writing a report on TEM, and was asked to consider the effect of accelerating voltage on the resolution. Since resolution in the light microscope is limited by the wavelength of visible light, we obtain much higher resolutions in a TEM...

Homework StatementA rocket is accelerated for 10 years at a constant rate of 10 m/s². Then starts braking at -10 m/s². Then goes all the way back to its starting point by again first accelerating 10 years at 10m/s² and then braking at the opposite rate for 10 years. How much time has it been for...

Hello All, would anyone know an expression for the heat capacity of an ideal gas, moving with relativistic speeds. For non-relativistic gas, the heat capacity is a constant, proportional to R (the universal gas const) Many thanks.

Relativity -- Sphere flattening due to relativistic speed Homework Statement Gum balls are spherical, and about 1.5 cm in diameter. Smarties are circular in one cross section, with the same diameter, but perpendicular to this circular cross section, they are flattened, with the smallest...

I want to know how force works in relatvistivc mechanics.I searched it and I know the formula but I didn't know how it works.Can you give some examples about force in Relativistic Mechanics. Thanks

Hi, I recently came across the idea that relativity can play a role in the repulsive force of a charge outside of a current-carrying wire. The situation described was when a positive charge (q) moves at the same speed and direction as the drift velocity of the electrons in the wire (assume...

In a number of threads over the years the idea has been discussed that if odometers were as well defined as (and as nearly realizable) as clocks, arguments we sometimes get that distance/length contraction 'disappears' when you stop, so it is meaningless, would have less weight. Now, nothing...

Can "relativistic mass" be a useful concept Many basic texts on relativity refer to the mass variation equation: m= gamma mo [gamma = Lorentz factor, mo= invariant(rest) mass] It seems that there are some good reasons including,for example, problems with definitions of...

Homework Statement Hi everyone, I'm having a bit of trouble with solving this problem: A ∏0 meson with rest mass m∏ has a kinetic energy K. It decays in flight into two photons whose paths are along the direction of motion of the meson. Find the energies of the two photons. Homework Equations...

Hi there, Is it true that the magnetic field of a straight wire is the same when the charges are moving at low speeds (v <<c) as when they are moving at relativistic speeds (v~c). The extra relativistic factor the magnetic field gets from the moving charges cancels upon integrating. According...

Supermassive black holes sometimes have extended relativistic jets emerging from the poles. They are HUGE and powerful and fast. Has there been research into the mass of such jets? Any other impressive statistics about just how much mass and energy these things contain?

So as I understand it Stephen Hawking and one other person I can't remember the name of worked on an equation to described the "temperature" of a black hole, that you can actually get information out of it. I know that there is one way it could happen with those vacuum particles in vacuum energy...

What is the defining moment when you use relativistic equations instead of classical ones? I have heard something as vague as "when it matters" and something about a ratio of rest energy before. I was hoping to know if there was a more concrete moment that defines when to use one or another. I...

Hey all, I was just wondering something which I couldn't get my head around tonight. If special relativity states that the speed of light is constant for all observers, regardless of the reference frame of any observer, then how is it possible for light to Doppler shift? Wouldn't the...

Homework Statement In the reference frame S', two protons, each moving at .5c, approach each other head on. Calculate the total kinetic energy of the two protons in frame S', and calculate the total kinetic energy of the two protons as seen in reference frame S which is moving with one of the...

I'm very noob at this and am a bit confused: Formula 1: E_T = \gamma \cdot m c^2 Formula 2: p = \gamma m v Formula 3: E_T^2 = (pc)^2 + (mc^2)^2 Formula 3 says a particle of negligible mass can have energy, but isn't this in contradiction to formula 1? Unless maybe the velocity of the...

Consider a wire with charges moving with speed 'v'and '-v' in frame F (with charge q at distance s away moving at speed u). In frame F', the charge q is stationary, and so the speeds of the charges in the wire are v+ and v-, where v- > v+ Hi guys, I have trouble following through the proof in...

Homework Statement A K_0 particle has a mass of 497.7 MeV/c^2. It decays into a -∏ and +∏, each having a mass of 139.6 MeV/c^2. Following the decay of the K_0, one of the pions is at rest in the laboratory. Determine the kinetic energy of the other pion after the decay and of the K_0 prior to...

Homework Statement a) A mass m starts at rest. Starting at t = 0 (measured in the lab frame), you apply a constant force f to it (lab frame). How long (in the lab frame) does it take for the mass to move a distance x (also measured in the lab frame)? Check that your answer makes sense in the...

Hi, I was looking up the formula for this on wikipedia and it said that the frequency shift is: \frac{\sqrt{1 - v^2/c^2}}{1+\frac{v}{c}\cos{\theta}} In the case where the the emitter is directly above the observer when the photon arrives it says it simplifies to: \gamma =...