Special relativity Definition and 1000 Threads

I will be giving a speech for my class and my teacher wants an abstract. I will be talking for about 45 minutes and i want to explain time dilation, length contraction, Einstein postulates, twin paradox, and the Muon experiment. But I am not sure how to put it all into an abstract.

Hi, So say you have a magnetic flux in a closed magnetic path circuit (like a TX core). Well I mean we draw arrows and stuff to indicate how the magnetic flux travels, but after watching this: I'm having trouble understanding why there is any flux moving through at all. Can someone please help...

Hi there, I am wondering what would be a good book to study the math of special relativity for a non physicist. I started with the " An Illustrated Guide for Special Relativity" by Tatsu Takeuchi which I found nice and easy book to start with. To put it in another way, where should I go after...

Let's say a train powered by electric third rail drives around without friction on a circular track, and light is shining out of the train windows, said light carries angular momentum, like light emitted from rotating or revolving things tend to do. Where does that angular momentum come from...

First I stand next to a point charge, then I start moving away or towards the charge, which causes the charge to be further away from me according to me (my ruler contracts according to an inertial observer), and as electric field of a point charge decreases with distance, the electric field...

Purcell has a paper in which he derives the magnetic field by assuming a charged particle travels alongside a conducting wire at the same velocity as the conduction electrons in the wire. The conduction electrons and the test charge are moving together but the positive charges are moving...

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...

I like a to ask a very simple question. I have read about time-dilation when it comes to SR. So, like: (1.) A and B are are rest and close to each other. (2.) B starts traveling at .5C relative to A, away from A, in a straight line. (3.) B comes back at .5C towards A. Now, according to SR, A...

Homework Statement A photon with energy E collides with stationary mass m. They form a single particle together, what is this new particle's mass and what is its speed? Homework Equations Energy-momentum 4-vector P=(E, px, py, pz) Possibly P2=m2 The Attempt at a Solution Using 4- momenta, the...

In special relativity, we can prove that the metric is -+++ for all observers and that is by making use out of lorentz invariance. Some on this forum say that it comes as a result of constancy of light and others say that Minkowski predated einstein in making that metric, which was confusing...

It is said phonon(not photon) in superfluid experiments could also produce similar upper-limit speed effect which I'm not sure if that's also Lorentz invariant. Another problem is that I can't dig out those paper that demonstrates this kind of effect. Anyone ever seen any of this paper? Thanks..

If you had twin 1 on the earth, and twin 2 fly to a star and back at a speed of v with the Earth and star separated by a distance L, twin 1 sends out flashes at intervals of t seconds (measured in his frame). Taking into consideration the numbers of redshifted and blueshifted flashes that the...

I always ask myself this question, and I think it is better to ask people that really know about this. Due to the impossibilities that Special Relativity poses, such as any object with mass not being able to travel at the speed of light. If we don't manage to at least scratch that speed, I...

I am a newbie to quantum physics but have been actively reading much about it for a couple weeks. However there are a few questions I simply cannot seem to find the answer to in regards to time dialation, the relationship between speed of light and time, etc. It seems like many sources repeat...

I was thinking about the superluminal speeds observed with quantum entanglement. Perhaps the particles are not really entangled, each of them just changes their spin with an in-built pseudorandom algorithm, allowing them to appear to be "in-sync" and thus entangled. This is just purely...

Hello. This is not a concrete problem, rather conceptual question. Homework Statement 2. Homework Equations 3. The Attempt at a Solution [/B] Spaceship with speed v with respect to the Earth is traveling from the Earth to say some distant star, which is distant L apart from the Earth looking...

Homework Statement a) The LHC was designed to collide protons together at 14 TeV centre-of-mass energy. How many kilometres per hour less than the speed of light are the protons moving? b) How fast is one proton moving relative to the other? Homework Equations The Attempt at a Solution a)...

Hello Everyone. I recently studied the Einstein special theory of relativity. I studied the thought experiment where a beam of light is thrown from a moving spaceship in the direction of its motion and the distance after a certain time interval was different from perspective of a man on...

Hello Forum, I have been studying special relativity and its unique phenomena (time dilation, length contraction, mass dilation, etc.) I would like to make sure that my understanding of these interesting phenomena is correct. For example, the length of an object is not an absolute. What we...

I'm doing a class on special relativity and when doing some problems, I'm never sure whether I should be using the Lorentz transformations (Eg. x' = γ(x-vt) or t'=γ(t- (v/c^2)x)) or the Time dilation and Length contraction equations to find t or x! Can anyone explain if there's any way of...

Is special relativity finished? It seems to me that there is more to special relativity. If we define C as equal to 1. (time = nanoseconds and length = feet) then we do a special relativity experiment an interval is defined. This interval is given by the square root of X squared...

Homework Statement Consider the following head-on elastic collision. Particle 1 has rest mass 2mo, and particle 2 has rest mass mo. Before the collision, particle 1 movies toward particle 2, which is initially at rest, with speed u (= 0.600c ). After the collision each particle moves in the...

Homework Statement Consider a searchlight on the ground that casts a spot on a cloud 1500 m overhead. If the searchlight is rotated rapidly−say, 40 ∘ in 1 μs−—how fast does the spot move in the Earth reference frame when the searchlight is directed vertically upward? I have solved this part...

Homework Statement [/B] Assume that 437 days is a reasonable limit for how long a human can endure constant-velocity space travel. Proxima Centauri, the star closest to our Sun, is 4.24 light years away from Earth. If you wanted to fly to Proxima Centauri within the 437-day limit in a rocket...

Homework Statement An electron e− and positron e+ moving at the same speed in the Earth reference frame collide head-on and produce a proton p and an antiproton p¯. The electron and positron have the same mass. The proton and antiproton also have the same mass. The mass of the proton is 1836.15...

Homework Statement Galaxy A moves away from galaxy B at 0.650 c0 relative to B. A spaceship leaves a planet in galaxy A traveling at 0.550 c0 relative to galaxy A. If the direction in which the ship travels is the same as the direction in which A is moving away from B, what do observers in B...

Homework Statement Antihydrogen is the only antimatter element that has been produced in the laboratory, albeit just a few atoms at a time. Each antihydrogen atom consists of a positron in orbit around an antiproton and has the same atomic mass as hydrogen. If an antihydrogen atom collides with...

Homework Statement In 2011, researchers at the OPERA experiment thought they had seen neutrinos with mass m and energy E = 28 GeV moving faster than light. The baseline between the source and the detector was 731 km, and the neutrinos seemed to arrive 60.7 ns early, compared to the maximum...

Homework Statement The highest energy protons have gamma factors around ##1.0*10^{12}##. (a) Our galaxy has a disk diameter of 30 kpc, which is ##9.3*10^{20}m##. If a photon and one of these high energy protons start traversing the galaxy at the same time, by how long will the arrival of the...

We know that clocks slow down if moving relative to something that's still and clocks speed up if still relative to something in motion. So, what if I was moving relAtive to something that's still and still, at the same time, relative to something that's in motion? How can time go quicker and...

Homework Statement I'm finding this very hard to get my head round! There's earth, and a star which is 6ly away, in the same reference frame. A starship sets out from the star, and another ship leaves Earth at the same time. Each one has ##v=0.6c##. What is the relative speed of the starship as...

Hi guys! I'm a pharmacist who has been trying to understand how time dilation and Lorentz contraction and etc. work, out of pure curiosity. I have been reading a course by Michael Fowler, which I link the 4th section of: http://galileoandeinstein.physics.virginia.edu/lectures/sreltwins.html In...

Homework Statement A train travels in the +x direction with a speed of β = 0.80 with respect to the ground. At a certain time, two balls are ejected, one traveling in the +x direction with x-velocity of +0.60 with respect to the train and the other traveling in the −x direction with x-velocity...

Let's say Bob floats in space. Bob's identical twin Joe moves past Bob at relativistic speed. As Joe is passing by, Bob gives him more speed by pushing him with his hand. Somehow I just happen to know that Joe will feel a smaller force pushing him than what Bob feels. So my question is: Why is...

Homework Statement Alice is driving a race car around an essentially circular track at a constant speed of 60 m/s. Brian, who is sitting at a fixed position at the edge of the track, measures the time that Alice takes to complete a lap by starting his watch when Alice passes by his position...

Homework Statement There are three observers, all non accelerating. Observer B is moving at velocity vBA with respect to observer A. Observer C is moving at velocity vC B with respect to observer B. All three observers and all their relative velocities are directed along the same straight line...

Homework Statement I have a particle moving with uniform velocity in a frame ##S##, with coordinates $$ x^\mu , \mu=0,1,2,3. $$ I need to show that the particle also has uniform velocity in a frame ## S' ##, given by $$x'^\mu=\dfrac{A_\nu^\mu x^\nu + b^\mu}{c_\nu x^\nu + d}, $$ with ##...

Homework Statement In a frame of reference A lights are on the x-axis at x = D and x = -D, where D = 0.6 x109. They flash simultaneously at t = 0. There's also a frame of reference A' moving at v = 0.8c. i) Where and when do the flashes happen in A'? ii) Therefore when would observers at...

Considering the enormous number of questions posed on this forum and other places, the concepts seem fundamentally flawed (because both are formally and practically unobservable). The calculations themselves (together with the Lorentz Transform) are highly error-prone and the results misleading...

Homework Statement I'm trying to confirm the speed of an antimuon in the \pi^+ \rightarrow \mu^+ \nu_{\mu} decay through the laws of conservation but it doesn't add up. Homework Equations [/B] 1.Energy-momentum relation: E^2 = (pc)^2 + (mc^2)^2 2. Rest masses: m_{\pi} = 139.6 \...

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...

Hi all, I've got a high school special relativity physics test coming up in a week and thought I should post here instead of under homework/coursework as I don't really have any set questions that I'm asking. My problem is that I can explain the visual effects we learned but not with enough...

[this thread was split off from https://www.physicsforums.com/threads/confusion-in-general-relativity.840710/] I read that Einstein gave the following argument: If we look at a rotating (and hence accelerated) frame from an Inertial frame, which is supposed to be away from all gravitational...

Homework Statement Five identical quintuplets leave Earth when they reach the age of 21, in the year 2121. Each quintuplet goes on a spaceship journey that takes T years, as measured by a clock in each spaceship. During the journey they travel at a constant speed v, as measured on earth, except...

Homework Statement One end of a vertical spring of spring constant k = 1900 N/m is attached to the floor. You compress the spring so that it is 2.50 m shorter than its relaxed length, place a 1.00-kg ball on top of the free end, and then release the system att = 0. (All values are measured in...

First, let me clarify if my understanding of length contraction is correct. Is it accurate to say that relativistic velocities not only affect the measured length of an object in the direction of motion, but also the distance to the object from an observer in the direction of motion? For...

Homework Statement A K0 particle is unstable and has a mass of 8.87x10-28 kg. It can decay into π+ and π- particles, each of mass 2.49x10-28 kg. Suppose that a K0 is moving in the +x direction and decays by this process, with the π+ moving off at 0.9c and the π- moving off at 0.8c. a) What was...

This is just a random thought, may be totally wrong. Euclidean geometry was originally described as a constructive theory in which the axioms state the existence (and implied uniqueness) of certain geometrical figures. These constructions are the ones that can be done with two concrete tools: a...

The metric $$ds^2=-R_1(r)dt^2+R_2(r)dr^2+R_3(r)r^2(d\theta^2+sin^2d\phi^2)$$ when changed to $$ds^2=-R_1(r)dt^2+R_2(r)(dr^2+r^2d\Omega^2)$$ upon setting ##R_2(r)=R_3(r)##, the later metric holds the name of isotropic metric. My question what is the difference between the first and the second...