The special theory of relativity describes the motion and dynamics of objects moving at significant fractions of the speed of light.

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Constant charge in special relativity

We had special relativity introduced in our course and used it to derive some facts. At one place we used the fact that if in frame of reference $U$ the electron has charge $e$, then it also has ...
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Calculus/Vector Calculus and so on in special relativity book recommandation

I want to learn calculus 1,2,3 vector calculus, analysis and so on in special relativity. But I never found a good and clear book/source on it. Can someone recommend an easy book or internet source on ...
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42 views

Calculate the relativity of time of an event occurred in different frames

Imagine we have a train which is moving with a velocity and there's an observer inside of that train and there is an observer that is outside of the train observing the train moving. There's a ball ...
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83 views

Special Relativity Kinematics Problem with My Wrong Solution [closed]

You are traveling toward a large fixed mirror at a constant relative speed 0.20 c0 . At t = 0, when the mirror is a distance d from you, you emit a light pulse from a lantern and then detect the ...
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83 views

Form of Spin Four-vector

The spin angular momentum of a gyro is represented, in special and general relativity, by a spin four-vector $S^{\mu}$. In the rest frame of the gyro, the spin four-vector takes the form ...
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69 views

Why aren't we all moving at the speed of light relative to photons? [duplicate]

Using basic logic.... We know speed and velocity is relative. My point is if we take our speed with respect to a photon moving in opposite direction we are practically moving at speed greater than ...
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1answer
62 views

Time dilation on Satellites due to GR

I am trying to determine the time dilation onboard a satellite (say GPS @ 20,000km) w.r.t an observer on the earth. I have already determined the special relativity component using: $$ t' = ...
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45 views

What will the point of view be when you move faster than light in a medium?

In water the light become slower to the point where electron in water moving faster than light (in the same medium). So in electron frame of reference what will electron's point of view be? From what ...
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1answer
53 views

Can I prove observed causality like this?

From an older exercise sheet in my relativity class which I completed, but didn't annotate enough to remember it everything was correct: Let $X$ be an inertial observer noticing that a spacetime ...
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2answers
69 views

Why is the relative speed between two inertial frames the same for observers in each frame?

Consider two frames $S$ and $S'$, moving relative to each other. If I stand still in frame $S$ and watch frame $S'$, I can measure its speed to be $V$. However, why is this speed the same as the ...
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1answer
80 views

relativistic addition of velocities using tensor notation? [closed]

I know the way of deriving the formula using usual lorentz transformation formulas,,but is there a way out of deriving it using 4-vector notation??please help
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34 views

Redirectioning photons through magnetic lenses

What shape magnet/s would I need to create parallel lines from the ends of a rod shaped magnet?or what shape of magnet would create parallel lines? Is this close?
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1answer
65 views

Question regarding the mass of an alpha particle when travelling at a speed approaching the speed of light [duplicate]

The speed of an Alpha particle is: 10^7 m/s. This is a speed approaching the speed of light. hence, should the (relativitic) mass of the Alpha particle vary?
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78 views

About twin paradox [closed]

It is not actually a twin paradox but I have no idea what to call it. So let's assume that there are two person named Alvin and Jack. Alvin drive a spaceship at the speed of 0.6c where Jack is ...
3
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1answer
84 views

Help me understand Pound and Rebka's experiment

I am a second year undergrad physics student and up until now have done some classical mechanics and some electrodynamics. For some reason I have always been really interested in light. A couple of ...
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0answers
55 views

What is the relationship between the “mass” of QFT and that of Newtonian mechanics?

In QFT we work with Lagrangians which contain terms $m$ such that the relativistic relation $E^2 = p^2 + m^2$ is satisfied. By classical analogy $m$ is called the 'mass'. We note that due to the ...
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41 views

Relativistic momentum (Lorentz boost) low velocity expansion

If I have a momenta $p^{\mu}=(E, p_x, p_y, p_z)$ and transform it via lorentz boost in x-direction with velocity v I'll get for the new 0th component $E'=\gamma E + \gamma v p_x$ why is this in the ...
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2answers
53 views

Do all moving object appear contracted?

In the derivation of Lorentz contraction my prof considered a rod moving away from you with speed $v$. In this case the rod appears shrunk by a factor gamma. But now let's consider a rod moving ...
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1answer
72 views

How can we say that difference in energy between 99.99% and 100% of speed of light is infinite? [duplicate]

How is it not possible for a particle to attain 100% speed of light and what will happen if it attains the speed of light?
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1answer
66 views

Spacelike interval and length contraction

I am having a serious trouble finding an agreement between the two facts in Special Relativity: (1) given two events $A$ and $B$ in spacetime separeted by a spacelike interval $s$, the distance in ...
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1answer
40 views

What is the physical meaning of $\alpha$ in this disintegration problem?

I am taking a course where I have to solve the following problem related to the disintegration of a baryon in a proton and a pion $(\Lambda \to p^+ + \pi^-)$: Assume that a $\Lambda$ particle with ...
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1answer
152 views

Behavior of the Electric- and Magnetic-field under time reversal and parity

The behavior of the electric- $\mathbf{E}$ and the magnetic-field $\mathbf{B}$ und time reversal and parity can be calculated in different ways. My first solution is to study the transformation ...
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13 views

Kinematic equations of a cascading particle decay

This paper discusses different measurable quantities that can be used to search for unknown particles at particle accelartors. For the following decay it introduces the invariant mass $m_{XY}$: It ...
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90 views

How to obtain Thomas Precession from lie algebra of the Lorentz group? [closed]

it seems to be possible that you can get the Thomas Precession just through the commutation relations of the Lorentz group. With Thomas Precession i mean, that in general the product of two boosts is ...
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127 views

Why is $V=(1/2) m^2 \phi^2$ for a free relativistic scalar field of mass $m$?

Bit of a basic question here but how come for a free relativistic scalar field of mass $m$ such as Klein Gordon theory, we take the potential to be $$V=\frac{1}{2} m^2 \phi^2$$ Is the mass term ...
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1answer
106 views

Is presuming that any linear uniform motion is transformed into another one sufficient to assume that Lorentz transformation must be linear?

I've read this condition in a script: The Lorentz transformation must be linear because any uniform motion must be a uniform motion in any inertial frame. All other proofs that I've read so far need ...
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1answer
63 views

Metric of an accelerated reference frame (without gravitation)

If we look at a flat Minkowski space-time (without any gravitation) an choose an accelerated frame of reference, what happens to the metric tensor is it still in Minkowski coordinates or will he be ...
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51 views

A Magnetic Vortex in a Magnetic Vortex

This is not to scale. Can a magnetic vortex be compressed into a flat disk using magnetic entrapment? Can a magnetic vortex happen inside another magnetic vortex?
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4answers
120 views

What if a light clock travels perpendicular to mirrors that make up the clock?

I'm guessing you're all familiar with the classic intuitive way of explaining time dilation: with a light clock traveling at velocity v directed at a parallel direction to the mirrors that make up the ...
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38 views

Magnetic field of a circular particle accelerator

Suppose there's a $500 \ GeV$ proton beam ($q=1.6 \times 10^{-19} C$) inside a circular particle accelerator, what would be the magnetic field intensity $B$ in Teslas required to keep it stable at a ...
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1answer
169 views

Why does an electromagnet attract iron according to Special Relativity?

I saw a video of Veritasium on "How Special Relativity Makes Magnets Work" and came up with a question. So please watch the video first before answering my question as it is related to the video. 1) ...
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1answer
114 views

Take advantage of time dilation or create a warp drive? [closed]

It is my understanding that time dilation slows down perceived time relative to the outside of a given vessel as it approaches the speed of light. Does that not mean that the inhabitants of said ...
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Why is special relativity still in use, if general relativity is more broad?

I always thought special relativity is only there because it is the building block for "The General theory of Relativity", until recently I encountered a text from my course book given below. A ...
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Einstein's famous equation $E = mc^2$

A fellow engineering student told me many years ago, that $E = mc^2$ means is that as an object of mass $m$ approaches $c$, the speed of light, it's mass increases and, at the speed of light, becomes ...
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3answers
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If electric fields can't pass through a grounded shield, how can a magnetic force be generated on moving charges outside a wire? [duplicate]

Say an electron outside a wire is moving with the same velocity as the electrons inside, then due to Lorentz contraction, an electric field would be generated in the outside electron's frame of ...
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1answer
58 views

Speed of a point on a concentric disk setup

I have been really solving this question that my friend and I had thought of while discussing about speed of light. Imagine there is a set-up where there is a light source that is surrounded by a ...
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488 views

“Warp-drive” thought experiment

Why wouldn't this "warp-drive" work? Assuming we can build a flywheel that can survive near light speed and have an onboard power storage or beamed energy that can spin it up to that speed and back ...
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What the common examples of $E=mc^2$? [duplicate]

this theory say's mass convert into energy and energy convert in to mass Whats he example of energy convert into mass?
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Twin paradox in special relativity [duplicate]

The Twin Paradox involves 2 observers, usually twins. Let them be named A and B. A remains at rest in the same reference frame as Earth while B is in a separate reference frame moving at velocity v, ...
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1answer
48 views

Coordinate Time and Proper Time/Simultaneity [closed]

At close to the speed of light, clock A is running slower than "stationary" clock B. Does clock A enter the future time reference of clock B as it slows down? Trying to understand where the forward ...
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1answer
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Relativity: easy spaceship scenario. easy questions [duplicate]

Your spaceship is traveling at 1/2*c and you approach Bob's spaceship going -1/2*c in the opposite direction. Relative to you, Bob is going the speed of light, and of course he has a giant ticking ...
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3answers
165 views

Derivation of $E=pc$ for a massless particle?

In classical mechanics, massless particles don't exist because for $m=0$, $p=0$. The relativistic relation between energy, mass and spatial momentum is: $E^2= (pc)^2 + (mc^2)^2$ . So it is said that ...
2
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1answer
68 views

How can parity be meaningful in an affine space?

I've recently begun a course in QFT (within a Physics Master's), and despite (admittedly limited) reading I can't get my head round the idea of parity. Here's what I think I understand: the Minkowski ...
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246 views

What is the correct relativistic distribution function?

General Statement and Questions I am trying to figure out the proper way to model a velocity/momentum distribution function that is correct in the relativistic limit. I would like to determine/know ...
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1answer
47 views

Range of a mediating particle

My book describes the derivation of the formula $R\approx\hbar/2mc$ by: $$(\Delta E)(\Delta t)\geq\hbar/2$$ The violation of energy conservation is $\Delta E=mc^2$ to create the particle’s mass. Also, ...
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4answers
144 views

Why light moves sideways?

Greatings! I'm trying to understand special relativity and have one question bugging me. In almost every book or video about the subject there is a thought experiment with moving light clock. I hope ...
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1answer
66 views

Special relativity, calculate velocity

Lets assume that a spaceship travels to a star 8 light-years away, in a time its crew considers to be 8 years. How do we calculate the speed of the ship? Is at as simple as saying: since the star is 8 ...
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1answer
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Integral Represation of Four Current with proper time

I have a question about the four current in covariant representation. the four current is defined as $$ J^{\alpha} = \binom{c\rho}{\vec{j}} $$ and i'm having a point charge, ...
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90 views

How can magnetic fields pass through a grounded shield?

Suppose an electron outside a wire is moving with the same velocity as the electrons inside, then due to length contraction, there would be excess positive charges per unit area causing attraction of ...
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How to spatially rotate the frame of reference Faraday Tensor? Special Relativity and Galilei Transforms

Hey I'm currently just starting out doing special relativity and I stumbled upon following problem: If I have the faraday antisymmetric tensor $F^{\alpha \beta}$ and I perform a spatial rotation of ...