Special relativity Definition and 1000 Threads

A nucleus of rest mass m initially at rest in the lab absorbs a photon such that its total energy becomes 1.01mc^2. I've calculated the energy of the photon to be greater than the change in rest mass of the nucleus this is on track because the follow up question is why is the required energy...

I am writing a paper about SR and GR. I have the following: Special relativity deals with inertial reference frames and flat space. General relativity deals with accelerating reference frames and curved space. Inertial reference frames are only an approximation that applies in a region...

When I studied special relativity for the first time, I encountered the exemple of a infinite neutral wire in the laboratory frame of reference, R, through which a constant current is running. In this frame of reference, the electrons in the wire are moving with a velocity +v and the ions...

If the speed at which light waves propagate in vacuum is independent both of the motion of the wave source and of the inertial frame of reference of the observer, why isn't the direction? Shouldn't the light travel directly upward from the point of emission and not diagonally, following the...

Hi. I know that space for an object in motion will contract, relative to an observer. We generally read that space contracts for the object in the direction of motion. But doesn't space around the object also contract? Can someone clarify this? Thanks.

So I just started taking Modern Physics and we are currently discussing special relativity. And needless to say, its giving me a headache. Here's my confusion: First, my Professor is Russian, and while his accent isn't so thick that I can't understand him, his grasp of English itself, is such...

I've written an open-source book on special relativity: http://www.lightandmatter.com/sr/ . It's a work in progress, but at this point it's fairly complete in its coverage of topics, and I would welcome feedback. "Open-source" means that the LaTeX source code is available, and it's under the...

Homework Statement You are exploring a newly discovered planet when a colleague contracts a deadly alien virus. Left untreated, it will probably kill him in 5 days, but the nearest medical station is 10 light-days away! How can you get him there in time? Homework Equations Δtp=L/v...

The basic premise of special relativity is that absolute motion is not detectable. Experimentally, this involves only two general cases, (i) detection via mechanical objects and (ii) detection involving light rays. Case ii readily resolves into two sub-cases, ii-a, detection involving...

Homework Statement bob and anna are in two space ships of proper length 100m; anna's ship passes bob's and is moving in the -x dir at v=0.75c. the front of anna's ship and the tail of bob's ship coincide at x=x'=t=t'=0. bob sits at the window in his ship and sees a clock inside anna's ship a)...

Homework Statement Homework Equations The Attempt at a Solution Hey, I would really appreciate some help with this. I have worked out the Lorentz factor to be 5.025. Am I right to assume that Δx = 200000km, and Δt' = 1.2s and I have to work out Δt and Δx'? If these are correct I have...

Homework Statement An object moves at v=0.94c in the frame of a laboratory for 32 us, decaying as it reached the other end. a) how far did it move in the frame of the laboratory? b) how long did the object travel in its rest frame? c) in the rest frame, how long is the laboratory? Homework...

Hello everyone :). I'm new here and wasn't sure where to post my physics question so here I am in the homework help section as my question is homework related... The problem I'm having is of very basic nature however I might have some trouble wording it. I understand an event is something that...

In Einstein's paper section 6 (I'm reading an English version online: https://www.fourmilab.ch/etexts/einstein/specrel/www/), it's said that one of the Maxwell Equations in frame K \frac{1}{c}\frac{\partial X}{\partial t} = \frac{\partial N}{\partial y} - \frac{\partial M}{\partial z}, where <X...

A quick question. It's been a long time since I had anything to do with special relativity, so I really can't remember much. But last night I was thinking about the "proof" of special relativity with the case of muons. So basically: Muons are created when particles hit the atmosphere. They...

Homework Statement A rod of length L_0 moves with a speed v along the horizontal direction. The rod makes an angle of θ_0 with respect to the x'-axis. (a) Show that the length of the rod as measured by a stationary observer is given by L=L_0\sqrt{1-\frac{v^2}{c^2}cos^2θ_0} (b)...

According to SR, there is no measurement that can determine whether an object is stationary or under motion. So if two metallic balls collide with each other, then aren't there motion between the two balls? Only then they will collide.

SR directly addresses only inertial frames. Can SR be applied to analyze accelerated frames? For example, consider a point on the rim of a rotating disc. I have see an analysis which makes claims by assigning an associated, instantaneous inertial frame comoving with the point at each...

10. The average lifetime of a pi meson in its own frame of reference is 2.6 x 10^-8 s. If the meson moves with a speed of 0.95c, what is (a) its mean lifetime as measured by an observer on Earth and (b) the average distance it travels before decaying, as measured by an observer on...

Here's a weird question where I don't quite know if length contraction or time dilation play a role. Say I have 2 spaceships moving towards each other. rest length of spaceship A is La and spaceship B is Lb. The pilot in A determines that time taken for the spaceship B to traverse the length...

Use the binomial approximation to derive the following: A) γ=1+.5(β^2) B)1/γ=1-.5(β^2) C)1-(1/γ)=.5(^2) I know the approximation is 1+(.5β^2)+(3/8)β^4+... A) is self explanatory but not sure how to derive B) and C)

I haven't specifically studied SR yet. My only exposure to it has been in the classical field theory section of Jackson's Electromagnetism and Landau Lifshitz Classical Theory of Fields. I understood what was going on and how it was related to the electromagnetic field etc but I don't feel as if...

hi. i am getting really confused about which should be the primed and unprimed values. id just like to check if what i did was right. thank you. :D Problem: A meterstick is glued to the wall with its 100cm end farther to the right in the positive direction. It has a clock at its center and...

I know that the example of time dilation and length contraction due to Special Relativity is usually given as the mountain top / sea level decays of muons created by cosmic rays but what is the evidence for mass change?

Homework Statement The creation and study of new and very massive elementary particles is an important part of contemporary physics. To create a particle of mass M requires an energy Mc2. With enough energy, an exotic particle can be created by allowing a fast-moving proton to collide with a...

Two spaceships approach an observer from an equal distance and from an opposite direction with an equal speed in the observer's intertial reference frame O. The speed of a spaceship in the intertial reference frame of the other spaceship S is 0.8c , what is the speed of one of the spaceships in...

Homework Statement Not sure whether to put this in advanced or intro forum, but ill just put it in here. So here's the context of the question: a linear swarm of 3 meteors are traveling at a speed of 0.9c towards our solar system (in the solar system reference frame). Each adjacent meteor is...

I have a little bit confuse on the Simultaneity I know if there are 2 coordinates. One coordinate S' is moving V relative to S. We all in inertial reference frame. like the following graph...

I'm thinking about a very basic scenario in special relativity, but I've got something backwards, and I could use help understanding why it's wrong. Suppose a rod R is moving past an observer O at speed v. The observer wants to know how long the rod is, so he starts his stopwatch as soon...

I got stuck in deriving the velocity of the particle from the acceleration equation. Here are the details of the problem. The acceleration of a particle with a relativistic momentum is \vec{a} = \frac{\vec{F}}{\gamma m} - \frac{\vec{v}}{\gamma m c^2}\left(\vec{F} \cdot \vec{v}\right)...

The example given is as follows : we have 3 space ships(numbered from left to right) placed in space moving at velocity V in the same direction (they are moving to the right) , each one can send a pulse of light to the others and the others can determine time reached. so each of them is an...

If someone stands up through the sunroof of a car traveling down the freeway at 60 mph and measures the speed of a beam of light they shine from a flashlight in the direction the car's going, they'll record it as c. This is intuitive (no need for relativity). Someone on the roadside, however...

SR is a theory based on flat space-time, and all of its effects are there in a flat space-time framework.My question is, how is SR compatible with GR, since GR uses curved space-time? Or to say it better how are time dilation, length contraction and relative simultaneity manifested in curved...

Hey guys, in classical mechanics Newton's law of universal gravitationa force says that the force between two bodies is equal to the product of their masses divided by the square root of the distance between them. So far, so good. In SR, lengths depend on the frame that we are in, and so the...

I only understand mass and energy according to Newtonian mechanics, Where mass is the resistance of a body to accelerate, or how much matter there is, and anything has mass is a matter. Energy is the ability to do work and it's not a matter. It was believed that mass and energy are two...

It is well-known that Newtonian's law of gravitation \Phi(\vec{r}) = -\frac{Gm}{|\vec{r} - \vec{a}|} for the gravitational potential ##\Phi## generated by a mass ##m## located at ##\vec{a}## is in several ways inconsistent with special relativity. What one could do is to modify the...

A firecracker explodes at the origin of an inertial reference frame. Then, 2.0 microseconds later, a second firecracker explodes 300m away. Astronauts in a passing rocket measure the distance between the explosions to be 200m. According to the astronauts, how much time elapses between the two...

Homework Statement I know that if you have 2 observers, "A", one at rest and the other "B" moving wrt "A" and if the moving observer shoots a projectile, then we can calculate the velocity of the projectile wrt "A" using the standard equation shown below. I was thinking what equation would...

Homework Statement If a clock in an airplane is found to slow down by 5 parts in 1013, (i.e. Δt/Δto = 1 + 5x10-13), at what speed is the airplane travelling? (Hint: You may need to use the binomial expansion for γ.) To be honest, I'm really confused about what this question's telling me...

Out of interest I'm studying a book "A first course in general relativity" which is a great book in my opinion because it explains the subject very well. I'm a beginner though and I have a hard time understanding one particular thing mentioned quite early in the book. I'm attaching a scan of a...

Hi. So the whole premise of special relativity seems to me to be hinged on the immutability of the speed of light, the fact that it is the same for every inertial frame of reference, and the fact that information and energy cannot travel faster than this. What really puzzles me is this whole...

Homework Statement A rocket of proper length 100m travels at a speed 0.6c relative to a space station, which is on the rocket’s flight path. I have so far had to work out that: According to an observer on the space station, the nose of the rocket is a distance of 200m away from the station...

I'm sure that most people on these forums are familiar with the similarities between compressible flow in aerodynamics and the relations between relativistic mass and rest mass in general relativity. A common example that's brought up frequently is the Prandtl-Glauert rule. After playing around...

Homework Statement A spaceship travels from Earth to the vicinity of the star that is measured by astronomers on Earth to be six light-years away. The spaceship and its occupants have a total rest mass of 32 000 kg. Assume that the spaceship travels at constant velocity. The time taken as...

Homework Statement Train is moving along the x-axis with speed v relative to platform, inside the train mosquito is flying with 3D speed v0. 1) Write mosquito s 4-speed components with respect to train coordinate system. 2) Using 4-vector component transformation write mosquito's 4-speed...

Homework Statement High energy photon of energy E collides with a low energy photon of energy 1eV. It forms an electron-positron pair. I have found the threshold energy as E=261GeV. I am asked to find the speed of the centre of mass at this threshold energy. Homework Equations E=γmc2 The...

Hi all, I can't seem to find any historic account of when those two theories got their (quite strange) names. Can someone point me to a source? One of the reasons I am interested in this is the persistent idea in popularizing texts, especially from the 1970's, that Special Relativity could...

In classical mechanics we can get a nice overview of the dynamics of a system by looking at its position-momentum phase space. Is there a useful analogue of this concept in special relativity? Can the dynamics of a relativistic system be represented by its phase space in the same way as is done...

How fast must a pion be moving, on average, to travel 9.0 m before it decays? The average lifetime, at rest, is 2.60 ✕ 10-8 s. (Answer in terms of c) I'm not exactly sure what equations I have to use but I believe it relates to time dilation. I originally didn't realize it was a time...

So here's the deal guys: I have a bachelor's in physics and have gotten an A in an undergraduate special relativity course but I do not feel that I fully understand the subject. I can do the problems in special relativity which require the various formulas involved in the subject and I even...