Sr Definition and 477 Threads

Hi everyone, I just wanted to share this really cool game MIT Game Lab made, it's called A Slower Speed of Light: http://gamelab.mit.edu/games/a-slower-speed-of-light/ Sorry if this is already commonly known among people interested in SR (probably is- but maybe there's a few people who...

Hi guys! I am looking for good lectures or books on special relativity and/or general relativity. Thanks in advance for any feedback.

I am reviewing to go back to grad school, and I need suggestions on a mechanics book to review. Having a readily available solutions manual is a huge plus since I am self studying. Recommendations? Thanks, Chris Maness

Hello, I have a doubt regarding the postulates of SR. The two postulates, according to Schutz, are: 1) No experiment can measure the absolute velocity of an observer; the results of any experiment performed by an observer do not depend on his speed relative to other observers who are not...

Hello I was reading something the other day and wondered what a two-particle lagrangian would look like in SR. I'm not exactly sure what lorentz scalar we can write down for the two particles.

GR can be used to show that the predicted time dilation on the surface of a planet equals the time dilation required by SR at that planet's escape velocity. Can it also be used to independently calculate the mass increase at that velocity without any reference to SR?

Hi, I know there are already other posts about extremal aging, but all of them are actually closed and none of them is actually answering to my doubt. I've just started T&W "exploring black holes", and I just faced the "extremal aging" principle. Actually, this concept doesn't fit very well...

Hello everyone, I have recently read a puzzling statement on my Electromagnetism (Chapter on Special Relativity) material regarding the Field Strength Tensor, F^{\mu\nu}, and its dual, \tilde{F}^{\mu\nu}. Since I've been thinking about this for a while now, and still can't understand it, I...

... I gained most of my elementary understanding of Special Relativity (SR) from books by Isaac Asimov. I made the continuing mistake on this forum, of either taking some things he may have said too literally, or misconstruing them altogether, and they are not entirely correct. In other...

v=? delta what/which X(distance) over delta what/which T(time) http://en.wikipedia.org/wiki/Special_relativity

Homework Statement Consider a particle in one-dimensional so called hyperbolic motion x(t)=\sqrt{b^{2}+t^{2}} where b is a constant. a) Find\gamma(t). b) Find the proper time \tau(t). (assume that \tau=0 when t = 0 c) Find x and v_x as functions of the propertime \tau. d)...

Einstein's article "on the electrodynamics of moving bodies", starts with talking about synchronizing clocks at different places and it is through this that Einstein explains concepts like time dilation and length contraction but in the present books about SR you hardly find things about...

Sorry if this has been asked a lot before but I did try a quick search for this but could find a simple answer. If I am at a fixed point on the equator and a friend is in a space station in a geostationary orbit, and ignoring GR, will their be time dilation between us? Or can we be...

If we consider a perfect relativistic fluid it has energy momentum tensor $$T^{\mu \nu} = (\rho + p) U^\mu U^\nu + p\eta^{\mu \nu} $$ where ##U^\mu## is the four-velocity field of the fluid. ##\partial_\mu T^{\mu \nu} = 0## then implies the relativistic continuity equation...

In classical mechanics you want to calculate the moment of inertia for hollow & solid: lines, triangles, squares/rectangles, polygons, planes, pyramids, cubes/parallelepiped's, circles, ellipses, parabola's, hyperbola's, sphere's, ellipsoid's, paraboloid's, hyperboloid's, cones & cylinder's...

According to Wikipedia, This definition doesn't sit well with me. Flux is defined as the rate that something passes through an infinitesimal surface, divided by the infinitesimal area of that surface. For example, the current flux (or current density), when dotted with a unit vector, gives...

Does \eta^{\alpha \beta}=\eta_{\alpha \beta} in all coordinate systems or just inertial coordinate systems?

I have just started studying Special Relativity in class and the concepts of Proper Length and Proper Time are giving me some issues. I understand the basics of length contraction and time dilation, but the idea of this "proper" time and length is giving me problems. One example in particular...

I would appreciate views on the following understanding of length and distance in SR, restricted here to inertial movement. This is the beginning of a follow up to the thread: https://www.physicsforums.com/showthread.php?t=724025 1. The spatial length of an object is the spatial separation...

Hi guys. I have something stuck in my head since a few days and I'd like to have your opinion about that. I don't know if I am missing something in my assumptions so please feel free to enlighten me. Here's the thing: considering two protons (or electrons), one fixed at the origin of the frame...

Homework Statement "In frame of reference S, an electron moving along the x-axis has energy 3mc2 and momentum magnitude √(8)mc Use the transformations of energy and momentum to find the energy and momentum magnitude observed in frame S′ moving with speed 4c/5 relative to S in the positive...

Hi, I've just started looking at SR and have got stuck with the first problem that considers 2D motion. I'm trying to work out the angle of tilt of a bar which is horizontal in one frame but moving horizontally and vertically wrt a second frame. I can't seem to pin down where the bar is at...

Is it possible for parts of GR and SR to be wrong even thought there are things about them that seem to be undeniable?

Suppose if travel towards the nearest star (alpha centauri) 4 light years away at 90% the speed of light does the distance between my spaceship and the star undergo length contraction? but i think in Wikipedia it its written as the distance undergo length contraction...

What is a good book on alternative theories of Special and/or General Relativity?

Sorry if this is a frequent topic, but I think it's interesting and probably worth repeating if it's come up often before. Let me lay out my question by example (and if anything is inaccurate feel free to point it out), and then I'll summarize at the end. It's easy to show in Classical...

What do you think about this explanation of EM-fields using SR? https://www.youtube.com/watch?v=1TKSfAkWWN0

Hi all. Hoping someone can give me a brief explanation re: a problem I'm having in trying to understand SR. Not looking for an argument, and won't engage in one. Just seeking a few views on the following issue I'm having with understanding. In his 1905 paper on Special Relativity, Einstein...

Is Einstein's SR a description of observations or a description of reality (or both)? It seems tome the distinction is important.

There has been a narrative that has run through a number of posts on special relativity. It establishes the idea that LET (Lorentz Aether Theory) is an interpretation of SR (Special Relativity). I personally believe this is a false narrative and that there is at least one fact that must be...

Homework Statement Consider two twins, Joe and Ed. Joe goes off in a straight line traveling at speed of 24/25 c for 7 years as measured on his clock, then reverses and returns at half the speed. Ed remains at home. Homework Equations What is the age difference between twins after return...

The two most famous "tests" for the accuracy of time dilation in SR are 1) the plane that flew around the globe with the atomic clock, and 2) the muon experiments on the mountain. I'm assuming, of course, that all the experimental controls are correct and so are the results. My question is...

I would be very grateful if someone would kindly explain this generalization of the Lorentz force law to the special relativity domain. I am not entirely sure if what I have jotted down is exactly as the speaker intended to convey. But here is what I have got. Please bear with me...

Sorry guys not a physicist!Only wish to know if there is agreement between Newton laws of motion and SR/GR in particular?I know these two don't match in some cases? What are they in simple words please!? Cheers

Homework Statement An observer at a station on the moon measures the time of a spacecraft passing with constant speed v. The front of the spacecraft passes him at 0 s and the rear at 0.2 μs. The observer measures the length of the spacecraft to be 1.5 m. Explain briefy the term...

Hi, SR is a mathematical theory with axioms. Can anyone provide a math proof of self consistency? Thanks

I want to discuss this because I afraid that the answer is no. In SR we stuck with the transformations from Poincare Group because this transformations leave invariant the exact form of the Lorentz Metric tensor. Any other transformation will change the components of the Lorentz Metric Tensor...

Pre-theoretically, we notice that objects have some property responsible for their varying dispositions to resist being pushed around in space, or to resist changes in motion given applied forces ("inertia"). So we introduce the term "inertial mass" to apply to the most physically interesting...

I'm curious about two things. Why did Einstein's 1905 paper contain no citations? Nowadays most papers have one or two pages full of citations, I don't know about back then but he must have had a few. Secondly, Einstein willed some of his Nobel money to his wife Maric. But that was a year or...

Hello friends, We all know that Michelson-Morley conducted an experiment which led to the proof that ether doe not exist. I don't know whether there is an alternative experiment of this,if there is i mean this...

Is: \mathcal L=-\frac{m}{2} u^\alpha u_\alpha a correct Lagrangian for SR (assuming the parameter is proper time rather than world time)? It leads to the correct EOM when plugged into the Euler-Lagrange equation, m\frac{du^\alpha}{ds}=0 Or is this the correct Lagrangian: \mathcal L=-m...

Is it ok to formulate the postulates of SR like so: 1) If two reference frames are in a constant rectilinear motion relative to one another, then the laws of physics take the same form in both of them. 2) If two reference frames are in a constant rectilinear motion relative to one another...

Precisely what is the difference between the (clocked) T flip flop and clocked SR latch? I have looked at the logic diagrams for both, but am wondering about functionality differences between the two. How do they differ in their functional use? All help is appreciated. Thanks! BiP

By the question in the title, I mean, do the so-called 4-vectors and tensors of SR transform as tangent vectors and tensors (in the sense of differential geometry) with respect to any transformation (local diffeomorphism) of the space-time coordinates or only with respect to Lorentz...

If a probe is sent to the Tau Ceti system and does not accelerate outside the solar system (keeps a constant velocity when passing the heliosphere) will it not experience relitivistic effects? Could it then send a message back to Earth in 50 years for us?

This is a spin-off of a parallel discussion, starting from: https://www.physicsforums.com/showthread.php?p=4281037#post4281037 The question is what SR predicts that an accelerometer in free-fall will read. This issue may be simply due to different people using a different meaning of "SR", but...

Homework Statement A Null-Lobur flip-flop (NL flip-flop) behaves as follows: If N = 0, the flip-flop does not change state. If N = 1, the next state of the flip-flop is equal to the value of L. a) Derive the characteristic table for the NL flip-flop. b) show how an SR flip-flop can be...

Homework Statement taken directly from Rindler A large disc rotates at uniform angular velocity ω in inertial frame S. Two observers O1 and O2 ride on the disc at radial distances r1 and r2. They carry clocks C1 and C2 they adjust to keep with clocks time with S, i.e., they have been adjusted...

This paper by Cacioppo and Gangopadhyaya deals with two variations on the Pole and Barn paradox. Both paradoxes are successfully resolved. However, with regard to the first paradox, an electromagnetic wave comes into being in one frame, but not in the other. I consider this to be a paradox in...