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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What exactly is different about the slice of space and lightcone concept in special relativity?
In Sean Carroll's book on GR, in the very first chapter about SR, he mentions how the difference between Newtonian concepts of space and time, and the view put forward in SR is how there is an "...
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Where is the increased mass reserved based on Einstein's mass-energy equation?
Assume a huge parallel-plate capacitor with plates located at an infinite distance away from each other. If we tend to move a positively charged object ($+q$) with a rest mass of $m$ against the ...
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Experimental verifications of relativity “in the classical limit”? [closed]
Note: This question is pretty basic and therefore probably has been asked before in another form -- please let me know which question this is a duplicate of in that case. (I couldn't find it myself.)
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Why can't only time dilation alone take place in special relativity, without length contraction? [closed]
In Einstein's special relativity, why can't just time dilation alone take place(without length contraction)? I mean if we slow down the time of the moving object/person, isn't it/or the person already ...
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In the Twin Paradox, can one twin travel backwards in time?
In the Twin Paradox, if the travelling twin, Betty, instead of returning to her brother Albert at home, continues her journey after a period of rest, why is causality not violated due to her brother, ...
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Does the linearity of transformations between inertial coordinate frames follow from the standard postulates of special relativity?
There are often multiple equivalent ways to formalize a physical theory, which may disagree on which propositions are fundamental axioms and which are derived theorems, but which (hopefully!) agree on ...
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Entanglement and light cones
Please consider the following thought experiment. The conclusion surprises me, I don't know if it is correct.
A and B are particles with entangled spin: Measure the up-down spin of A and B then the ...
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Positive values of Mandelstam variable $t$
Is it possible for the Mandelstam variable $t$ to reach positive values in the quasielastic charged current neutrino-neutron scattering?:
$$\nu_{\mu} + n \rightarrow \mu^- + p$$
(don't assume that ...
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A question on the nonrelativistic limit of special relativity [closed]
In special relativity, one typically works in the spacetime manifold with the Minkowski metric:
$$ds^2=-c^2dt^2+d\vec x^2.$$
However, I find it intuitive that in the nonrelativistic limit, if one also ...
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Equivalence principle and principle of relativity
If equivalence principle was not true could we have almost inertial reference frames near the earth? Specially, is it was possible for a person in a train to know that if it is standing still or it is ...
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Is modified mass of special relativity inertial or gravitational? [duplicate]
Is modified mass of special relativity
$$m= \frac{m_0}{\sqrt{1-(v/c)^2}}$$
inertial mass or gravitational mass?
I hope $m$ be both of them: we know accelerating massive particles to speed of light is ...
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Is it correct that you can change light's velocity but not its speed? [closed]
A laser is shone down the center of a vacuum corridor 1 light-year in length. The corridor has a lateral motion (perpendicular to the laser) of 10mph. Does the light hit the center of the far end, or ...
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Is there any formula for momentum which works for both particles with or without mass?
The formula
$$p=\gamma mv$$
can give us momentum for only the particles with mass. In case of massless particles(photons), it turns to $0/0$ indeterminate form. So it just tells that momentum can have ...
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The twin paradox: a paradox in the paradox
I have a problem with the twin paradox: the $AB'C$ path is longer then $ABC$ path.
But the legend under the picture says that $ABC$ will age more then $AB'C$ which is longer than $ABC$!
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Time dilation will not determine whether the speed of light is isotropic or anisotropic [duplicate]
It is well known that one can create an alternate form of special relativity where the speed of light is different in different directions and yet make all the same predictions of orthodox special ...
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Why does the Lorentz transformation preserve the speed of light specifically under the Minkowski metric but not under alternative quadratic forms?
I know that Lorentz transformations are defined as the linear transformations preserving the Minkowski metric $s^2 = c^2t^2 - x^2 - y^2 - z^2$. But suppose we consider an alternate metric $s^{′2} = c^...
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Special theory of relativity paradox (buoyancy)
We have a submarine (sub) in a frictionless liquid and the average sub density is equal to the density of a liquid. Sub is fully submerged not touching the bottom.
Now the sub moves at near speed of ...
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How can we define total energy and rest energy in relativistic energy equation?
I have learned that, derivation of mass-energy equivalence leads to $K=\gamma mc^2 -mc^2$, and it means that $\gamma mc^2$ is the total energy and $mc^2$ is the rest energy. But doesn't this equation ...
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An object cannot travel faster than the speed of light, but what about the relative motion of two object traveling in opposing vectors? [duplicate]
If mass m1 is traveling along vector v1 approaching the speed of light.
and mass m2 is traveling in a directly opposite vector v2 approaching the speed of light,
considering only contemporary ...
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A problem with a current-carrying sheet's magnetic field as viewed by an observer moving perpendicular to the current direction (Part I)
In my previous question, entitled a problem with a current-carrying wire's magnetic field as viewed by an observer moving perpendicular to it, @Dale answered that:
so indeed, as you mentioned, in ...
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Is the magnetic field produced by a wire current $I$ on a moving train observer the same for a stationary observer?
Well, this question really doesn’t aim to be about relativity but the behavior of electromagnetic fields in a scenario. However, if the answer is due to relativity, please tell me.
Suppose there is an ...
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Does the inertia of a body depend on its energy content?
The question title is taken from Einstein's 1905 paper which shows that the rest energy is $E_0 = mc^2$. In other words, an object's inertia -- the tendency to resist changes in motion -- is dictated ...
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Why does temperature increase mass?
We learn that $E_0=mc^2$, that is, internal energy is a form of mass. Also, kinetic energy does not relate to mass at all, and the complete relativistic energy momentum equation is
$$
E^2=(mc^2)^2+(pc)...
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If differentiation and integration are defined via limits, does that mean physics is describing the real world only approximately? [closed]
The derivative of a function $f(x)$:
$$
f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}
$$
For example $f(x) = x^2$:
$$
f'(x) = \lim_{h \to 0} \frac{(x+h)^2 - x^2}{h} = 2x + h
$$
which is never ...
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Did Maxwell's mechanical model for $E$ and $B$ account for causality and finite propagation of disturbances even before he derived EM waves equations? [closed]
I have studied that Maxwell got intuition for EM waves after his discovery of "displacement current" as change in one field will generate another field (like- time varying E gives B) and the ...
