Master Special Relativity with Expert Help and Solutions

Recent questions in Special Relativity
Landyn Allison 2023-03-25

What makes the planets rotate around the sun.

Heddertyk1j 2023-02-16

What is the distance from the Earth's center to a point in space where the gravitational acceleration due to the Earth is 1/24 of its value at the Earth's surface.

l1voyax 2023-02-11

What is proper motion.

powerinojSs 2022-11-22

In order to calculate the cross-section of an interaction process the following formula is often used for first approximations:$\sigma =\frac{2\pi }{\hslash \phantom{\rule{thinmathspace}{0ex}}{v}_{i}}{|{M}_{fi}|}^{2}\varrho \left({E}_{f}\right)\phantom{\rule{thinmathspace}{0ex}}V$${M}_{fi}=⟨{\psi }_{f}|{H}_{int}|{\psi }_{i}⟩$${M}_{fi}=⟨{\psi }_{f}|{H}_{int}|{\psi }_{i}⟩$$\varrho \left({E}_{f}\right)=\frac{\mathrm{d}n\left({E}_{f}\right)}{\mathrm{d}{E}_{f}}=\frac{4\pi {{p}_{f}}^{2}}{{\left(2\pi \hslash \right)}^{3}}\frac{V}{{v}_{f}}$The derivation of this equation in the context of the non relativistic Schrödinger equation. Use this formula in the relativistic limit: ${v}_{i},{v}_{f}\to c\phantom{\rule{thinmathspace}{0ex}},\phantom{\rule{1em}{0ex}}{p}_{f}\approx {E}_{f}/c$Very often books simply use this equation with matrix element derived from some relativistic theory, e.g. coupling factors and propagators from the Dirac equation or Electroweak interaction. How is this justified?

Bailee Richards 2022-11-22

Why does the azimuthal angle, $\varphi$, remain unchanged between reference frames in special relativity?I think this comes from the aberration formula, showing dependence only on the polar angle, $\theta$. The aberration formula is:$\mathrm{tan}\theta =\frac{{u}_{\perp }}{{u}_{||}}=\frac{{u}^{\prime }\mathrm{sin}{\theta }^{\prime }}{\gamma \left({u}^{\prime }\mathrm{cos}{\theta }^{\prime }+v\right)}$where ' indicates a property of the moving frame.

Hanna Webster 2022-11-13

If time in systems moving with different speed goes differently, does speed of entropy change differ in these systems?

bruinhemd3ji 2022-11-08

The mass of a body on the surface of the Moon is greater than that on Earthaccording to the equation $E=m{c}^{2}$

Amy Bright 2022-11-04

Is time travel possible?Time travel - often featured in movies, books, or facetiously in conversation. There are also theories treating time as simply another dimension, which to the layperson might imply forward and backward movement is possible at will. But what do we know scientifically with respect to the possibility or impossibility of controlled time travel? Are there any testable theories on the horizon that may support or eliminate controlled time travel as a possibility?

Alvin Parks 2022-11-03

We know that$d{s}^{2}={g}_{\mu \nu }d{x}^{\mu }d{x}^{\nu },$How to calculate $ds$?

cousinhaui 2022-11-01

On a relativistic train a kitchen timer is set to give a signal after 4.95 minutes. You are standing next to the rail road tracks. In your reference frame it takes 8.95 minutes for the kitchen timer to signal. What is the speed of the train?

Chloe Arnold 2022-10-29

If there were a vast lever floating in free space, a rigid body with length greater than the width of a galaxy, made of a hypothetical material that could endure unlimited internal stress, and this lever began to rotate about its middle like a propeller so that a person looking at the universe would simply see it spinning at a gentle pace like a windmill, would not its ends be moving many, many times the speed of light?

Kamila Frye 2022-10-29

Why does Lorentz factor not hold for relativistic mass when we apply it to photons?We know that the photon itself is massless particle ${m}_{0}=0$. But we also know, that the mass of the objects does increase with their energy. And we know that under certain circumstances (gravity, collision with objects) the light does behave like a beam of particles that do have a mass.Now, this is the equation to get the (relativistic) mass of the object with certain speed:$m=\frac{{m}_{0}}{\sqrt{1-{v}^{2}/{c}^{2}}}$We already do know some things: ${m}_{0}=0$, $v=c$.$m=\frac{0}{\sqrt{1-{c}^{2}/{c}^{2}}}$$m=\frac{0}{0}$Expression $\frac{0}{0}$ is not equal to 0. So what is this?

Raiden Barr 2022-10-22

Since time slows down and length contracts, when we travel almost at speed of light, if the speed of light (or EM waves) remains same and the wavelength of light remains same, do we measure the wavelength more than it actually is?

raapjeqp 2022-10-22

Dark energy physically can be interpreted as either a fluid with positive mass but pressure the negative of its density (pressure has units of energy/volume, and energy is mass), or a property of space. If it's a fluid, it should add to the mass of black holes like any form of energy (no hair), and the black hole should grow? However, if dark energy is a property of space, then this won't happen. Is my reasoning correct that we can differentiate (in theory) by looking at black hole's growth rate?

caschaillo7 2022-10-21