# Questions tagged [special-relativity]

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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### Is the defintion of *inertial reference frame* given by Blandford and Thorne acceptable?

Edit to add: A simple explanation of my objection to Blandford and Thorne's definition of inertial reference frame (which they use synonymously with inertial frame) is that, if I'm in free float, ...
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### Wifi near the speed of light

I have a hypothetical question that hopefully makes sense considering only the rudimentary amount of knowledge I have on Relativity. Assume I am in a spaceship orbiting around a spherical satellite, ...
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### Dirac spinor and Lorentz group

How does the reducibility of lorentz group ensures that there exist two types of particle i.e left-handed and right-handed (weyl spinors)?
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### Apparent rotation in connection with observation of Lorentz contracted objects

My question is related to the so called invisibility of Lorentz contraction, but I am essentially concerned with part related to the apparent rotation often mentioned in explanation of the phenomenon. ...
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### Can you derive the Dirac equation from the Dirac-von Neumann axioms?

The Dirac von Neumann axioms say nothing about relativistic QM, can I invoke relativistic effects and derive the Dirac equation from the Dirac von Neumann axioms? If so, how does one go about it? If ...
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### Relativistic observers moving on equilateral triangle

In the laboratory frame two observers A and B are moving along sides of na equilatera; triangle with equal sides, as shown in the figure below. What is velocity of B with respect to A?
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### Maximum exhaust speed of relativistic rocket?

In this document "a transparent derivation of rocket equation", the author writes (on the last page): These are the classical and relativistic rocket equations. For the relativistic case, there ...
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### Lorentz transformation of Interaction therm in Weinberg book

In Weinberg book The quantum theory of fields he says that one condition for the $S$ matrix to be Lorentz invariant invariant is that the interactions therm takes the form $$V(t)=\int dx^3H(x,t)$$ ...
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### Lorentz Transformations and Reversing Boost Order to Give A Different Transformation

[Question] Find the matrix for Lorentz transformation consisting of a boost of speed $v$ in the $x$-direction followed by a boost of speed $w$ in the $y'$ direction. Show that the boosts performed in ...
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### Does the conservation of 3 and 4-momentum implies the conservation of relativistic energy?

In special relativity, we require 3-momentum, 4-momentum and energy to be conserved. This gives three equations. However, after solving some exercises on relativistic dynamics, I find that I usually ...
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### Problems on special theory of relativity [on hold]

From an observational post E on the Earth, two ballistic missiles, each of rest length l from nose-tip to tail-end, are observed to fly past each other, with the same uniform relativistic speed c/...
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### Distance a muon travels in a pion rest frame

I have a question regarding a pion at rest (with a mean life time of $2.5\times 10^{-8}$ s) which decays into a muon (of mean lifetime $2.2\times 10^{-6}$ s), and a neutrino. I've found the velocity ...
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### Momentum conservation in special relativity

In my textbook Kleppner, this question is given in the problem bank. We define momentum 4-vector in Kleppner as: ...
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### Can the centrifugal inertial force, acting on ultrarelativistic electron in a circular orbit, be expressed in terms of its kinetic energy?

From classical mechanics we know that centrifugal inertial force, acting on an electron in a circular orbit of radius $R$ in relatively slow motion ($v \ll c$), can be expressed in terms of its ...
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### Relativistic Computer Processing Power

Modern computers generally perform one step at a time at a given frequency (I know, an over-simplification). However, if one had a computer program, and wanted to speed it up, one could get on a ship ...
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### How do permanant magnets work (In terms of electric charge and relativity)

I've been reading about magnetism from the point of view of reference frames and relativity. The concept of a test charge moving next to a wire (and how the choice of reference frame will cause ...
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### Is there an ambiguity between the motion of an aircraft propeller and time dilation in special relativity?

We know that the faster a propeller rotates, the faster the attached vehicle (airplane, submarine, etc.) moves. (Assume that the propeller is normal to the motion direction.) On the other hand, ...
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### Tensor indices from Ramond

I'm working through Pierre Ramond's "Field Theory: A Modern Primer". I can't connect the steps in I.2. Eq 2.6 (p. 7) gives a property of two linear transformations in relation to the Minkowski metric,...
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### Confusion regarding length contraction [duplicate]

I understand that length contraction is a consequence of the relativity of simultaneity. I found this spacetime diagram online: Here it's clear that what constitutes a rod for one observer, is a ...
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### What is the relativistic form of the dynamic pressure of a fluid? Is it a Lorentz-invariant quantity?

If one moves a plate through the air at a uniform velocity $v$, the pressure exerted on the area $A$ of the plate is: $$p=\frac{1}{2}\rho_{air}v^2 \space .$$ This pressure is measured by the ...
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