Length contraction Definition and 474 Threads

Hi! I have been pondering a scenario involving a paradox with length contraction. I brought it up with my physics professor, and I somewhat understand what is supposed to happen, but I'm still somewhat confused, so I was wondering if you could help me figure out what is going on. In this...

I understand why an object in a moving frame would be longer, but not why one in a stationary frame would be shorter. Wouldn't one in a stationary frame be the same as the object would be in the rest one? I understand the time dilation behind it, it's just that the rest of the reasoning makes no...

I am trying to get another insight in what I think is currently for me a contradiction. I have searched the forums, and the web but come to the following assertion: The coordinate distance is the computation of the proper distance times the gamma-factor, while the "coordinate" length is a...

Let's suppose that we have a rod which is 2 meters long in its rest frame. Its rest length can be defined as a set of points which do not occupy the same place, measured in a frame which is at rest with the rod as a whole. Now if we travel relative to the rod, it gets length contracted, I...

Since many authors call simultaneity between events a convention, and that under the specific set of rules we may choose a convention or a coordinate system relative to an IRF (or non-inertial) to describe space time, I wonder what's the relation between this and the effects of length...

Homework Statement A relativistic conveyor belt is moving at speed 0.5c relative to frame S.Two observers standing beside the belt, 10 ft apart as measured in S, arrange that each will paint a mark on the belt at exactly the same instant (as measured in S). How far apart will the marks...

The three main effects of SR occur in inertial frames and change the description of space-time relative to a particular observer. My question here is how do these effects occur on Earth, since we know that motion on Earth is non-inertial. I know that we travel at small speeds and that we can't...

What should it be, {sin(ωt-\frac{k}{n}x)} or {sin(ωt-nkx)}? I am contemplating this with respect to the proper waveform in a medium, following specific rules, particularly when it comes to the dispersion relation and ultimately what this would mean in the context of the Lorentz transformations...

Hi all, I tried searching for this but failed to find an answer to my question. I am having an issue with properly interpreting the equations for time dilation and length contraction. Let's assume that I am standing still and a train is passing by next to me (moving with uniform velocity). Let...

Homework Statement Show that the experiment depicted in Figure 2.11 and discussed in the text leads directly to the derivation of length contraction. Figure 2.11: Homework Equations d=v*t Requested result: L=L0\sqrt{1-\frac{v^2}{c^2}} The Attempt at a Solution In K the...

I had a quick question about Time Dilation and Length Contraction. Are the two just different ways of measuring/describing the same effect? Or rather they both follow as a consequence from one another? i.e. I can find how much a length is contracted by finding the dilated time interval and...

I found a funny video on youtube, but I am not totally convinced by the argument. It says that a pure magnetic field caused by a current in a wire can lead to a combined electric + magnetic field in a moving frame. It explains more or less convincingly that this can be understood as a...

Imagine two asteroids which are separed by 1Ly distance. They are in uniform velocity (.9c) with respect to an observe in space. So from the observers point of view (rest frame), does the distance between the asteroids (ie. 1Ly) appear contracted?

Length Contraction:Does the object or travel distance shrink? I had always thought that length contraction meant that the object itself shrunk but I stumbled across an article where they said "Because of length contraction the photon doesn't travel any distance at all. Which is it? Any help...

Consider two iron rods of about 10 metres separated by 10 metre. They are in series position and not connected in anyway. If the rods are passing nearby an observe with a velocity of 90% speed of light, then what would he observe? 1) does the separation between the rods (ie 10m) undergo length...

Suppose I'm standing on Earth and i see an iron rod accelerating through space with a rate of 1m/s^2. Will it undergo length contraction after reaching a speed nearly to the c? Will there be any deformations to a spinning disk?

Hi, As is well known, Relativity claims that a rod of a given proper length will appear length contracted when measured by a moving observer. Now consider a rod of length L and observer initially at rest relatively to it, with one end of the rod at the observer's coordinate x1(0) and the...

The problem has been shown in the picture. Because of relativity, both the guys on the ground and on the vehicle would observe length contraction. So the destination of the guy on the vehicle---the galaxy, would be more closed to him. If the vehicle is replaced with the light, which means the...

Hello All, I like to think that I have a decent background in physics and related material, but I confuse myself quite easily on, well, everything. I guess I think about it too much, really. So feel free to give complex answers and I will do my best to follow along accordingly. Anyways, here...

Suppose I am in a stationary frame of reference S and there is a lamp post at a distance X from my origin in the positive X direction. Say you move at a velocity V along that axis and the distance of the lamp post in your frame of reference S' is X'. Then by Lorentz transformation equation X'...

Can anyone help me with this thought experiment. I have a spaceship moving at very close to the speed of light. Inside are the captain and two crew members. The captain is positioned at the front of the spaceship with a clock and a light. One crew member is positioned at the back of the...

Say we have two inertial observers Bob and Alice moving relative to each other at a significant fraction of the speed of light c (say 0.5c). Bob is moving to the left relative to Alice and Alice to the right relative to Bob. When their origins cross, a pulse of light is emitted to the right...

can both time dilation and length contraction occur for the same observer? i don't think it is possible since then c=reduced length/increased time which is impossible(since c is constant)... Am i wrong?

Okay because my previous post of similar kind was I guess rather too full of thought experiments and ideas that nobody actually responded to it except for one user then I will try to explain the same thing here only much simpler. A few situations. so there is this site...

I've been trying for a long time to get an answer to the question, "What is the physics or mechanical explanation of contracting physical objects and the distances between them?" I understand that the phenomenon is theorized to depend on different observations from different frames of reference...

Hello, I am a bit confused about the length contraction formula. The formula is : l=lo*sqrt(1-u^2/c^2), where lo is the distance measured in a frame at rest with the moving object. Now I was looking at a problem where a spacecraft just as it touches the finish line (event 1) a message from...

If an object were to approach the speed of light, its length, as measured by an observer, would become shorter and shorter. But what about the view of the speeding object? If the object is approaching the speed light, then would the world surrounding it appear to be shorter as well? I say...

Can someone please clarify for me whether length contraction in special relativity is considered a physical effect (a contraction of a cohesive material) or a kinematic effect (applied to the space the material occupies)? I've been thinking about Bell's Spaceship Paradox this week and realized...

As I've just recently started studying relativity, I need some help with these basic concepts. So this thread is about length contraction. Can somebody explain the effects of it, since I've already found out some things, like the existence of the invariant proper lenght, the fact that...

well,i found this article and i find it simple to understand. But is this article totally correct? Here is the link:http://m.sparknotes.com/physics/specialrelativity/kinematics/section2.rhtml

Homework Statement Two space ships, each a hundred metres long when measured at rest, travel toward each other with a speed of 0.85c relative to the Earth. Homework Equations λ = 1 / √1 - (v2/c2) x' = λ(x - vt) L' = L / λ The Attempt at a Solution Well to be honest i may be...

Hi all, Page 94 of Special relativity by AP French has a worked out example that puzzled me. This is the example: Frame S’ has a speed v=0.6c relative to S. Clocks are adjusted so that t=t’=0 at x=x’=0. Two events occur. Event 1 occurs at x1=10m, t1=2E-7s (y1=0, z1=0). Event 2 occurs...

I've recently been thinking more about special relativity, and while I understand the Lorentz factor and how to apply it to find correct solutions, I'm still stuck on the link between the effects of length contraction and time dilation, are they permutation of the same thing from different...

I've recently been thinking more about special relativity, and while I understand the Lorentz factor and how to apply it to find correct solutions, I'm still stuck on the link between the effects of length contraction and time dilation, are they permutation of the same thing from different...

I understand the concepts of time dilation and length contraction in SR. I also understand the concept of time dilation in a gravitational field. But what about length contraction in a gravitational field? Is there such a thing and can it be derived from the Schwarzschild metric?

If I am moving through space, things in front of me contract in the direction parallel to my movement. Does this also occur to objects behind me? For example, I look behind me, would things be contracted? As always, thanks.

Lets say we have an infinite charged wire with a line charge \lambda on it. Now when I move with respect to this wire the E field will increase do to length contraction. And there will also be a B field that we could calculate with ampere's law. But the increased E would make it seem...

Mach's principle is considered falls by many because mass anisotropy would not be consistent with the Huges-Drever experiments, which showed the isotropy of nuclear resonance. However, anisotropy appears as well in GR in the form of radial length contraction, which can be interpreted as increase...

My understanding is that as I move, from my FoR all objects and space itself (according to Einstein) contract along the direction of my movement. This length contraction occurs for all space and objects in front of me for an infinite distance. Furthermore, relative motion is relative, and the...

I am confused about these two concupiscences of the consistency of light. One of my books/notes says that time dilation and length contraction do not happen at the same time because they are 'the same thing' which kind of makes sense but the other says "when we reach relativistic velocities both...

http://https://www.physicsforums.com/attachment.php?attachmentid=56297&stc=1&d=1362318192 problem:- The situation is shown in attachment. the right angled frame of rods (in stationary ) is moving at speed v perpendicular to its hypotenuse. according to length contraction the corresponding...

according to special relativity theory, any object that has relative velocity also has lorenz- contraction L' = L0 *sqrt (1-(v/c^2)) it sounds odd that this is only kind of length contraction known to exist. why there are no other kind of length expansions or contractions, or are them...

Homework Statement Hey All; I am trying to follow along with the following example in my book, but I am getting lost somewhere. "We can perform another gedanken experiment to arrive at the same result (showing that length contraction is described as L=Lo/γ; this time we lay the meterstick...

This is a very common topic especially regarding the apparent slowing down of time, the twins paradox etc. I have come across the figures for a muon and the relativistic effects that allow it to reach the Earth's surface despite its very short life. The relevant transforms show length...

Consider observer A at rest, seeing observer B traveling in a rocket at high speed towards a star C. Star C is at rest w.r.t. A. A in his frame sees B's rocket to be length contracted. B considers his distance to C to be shorter than (contracted) compared to what A sees. I seem to be...

Hello, in my other topic members on the forum helped me to understand time dilation by using Minkowski spacetime diagram. Now i would also need some assistance with explaining length contraction in Minkowski spacetime diagram. I have observer Žiga in his frame ##x,ct## and observer Ranja...

I am on a spacecraft as it makes a journey between two planets. I use a lightpulse to measure the distance before I set off, I then accelerate to a speed that is close to the speed of light and measure the distance again. I find that the distance when I am stationary (relative to the planets)...

Hi Consider a spaceship at rest in space, this ship is equipped with a bomb connected to two rings. Once the rings connected to each other, the bomb explodes making the ship also explodes. The proper distance between the rings is one meter. Now consider a conducting rod of proper length one...

Inspired by Aziza's question i came up with a similar, seemingly puzzling question. Imagine a space-platform with a big cylinder on it. The cylinder has a hole drilled in, with a bomb-button at the end of the hole, which would trigger a bomb destroying the whole galaxy. A terrorist is on that...

Length Contraction "Ether wind" Homework Statement Due to the ether wind, anything that moves along it is "contracted". The Attempt at a Solution Taking L1 to be contracted length, (L1)2 = (L1x)2 + (L1Y)2 = (L10,X/γ)2 + (L10,Y)2But what they wrote is the opposite..