Length contraction Definition and 477 Threads

A spaceship with an arbitrarily large quantity of fuel cells departs Earth and accelerates away from it with a fixed trajectory until it reaches .9c. It continues to accelerate, but never reaches c because that is impossible for any object with mass. From the frame of reference of the crew...

If I am moving through space at a velocity that is a significant fraction of c, are all objects ahead of me in my path contracted in the direction of my travel for an infinite distance? In other words, are planets and stars from right in front of me to the edge of the known universe contracted...

Hi, I have attempted the following questions but I am unsure of my answers/method. Could you guys please help me through? A super fast spacecraft is moving at a speed of 0.80c with respect to the observers on Earth. The spacecraft leaves Earth in May 2004 on its way to a distant solar...

U is the universal rest frame. A and B space ships pass U at t=0, moving at v. Both experience equal length contraction in the x direction. If length contraction is a result of em deformation in response to acceleration, then length expansion should be the response to deceleration. If the B...

Suppose you've just established the existence of time dilation using Einstein's 1905 postulates and the light clock. Is there any nice, easy way to go on and prove length contraction? Here are a couple of incorrect arguments that I've been guilty of using in the past: Symmetry: The Lorentz...

why does space time not contract uniformly in every direction around a fast moving object?

Homework Statement Two momentarily coincident observers approach a small and distant object. One measures the object to be twice as large as the other's measurement. Find their relative velocity. Homework Equations Lorentz Transforms L/L_0 = \sqrt(1 - \beta^2) The Attempt at...

Homework Statement A spaceship moves past you at speed v. You measure the ship to be 300 m long, whereas an astronaut on the ship measures a length of 356 m. Find v. Homework Equations L=L1sqrt(1-v^2/c^2) The Attempt at a Solution I have tried this by using the above formula. I...

Preparing for a classical prelim by going over previous exams. Homework Statement A relativistic meter stick moves with speed v in the lab. It collides head on with an impenetrable wall completely inelastically, thereby coming to rest in the lab frame. What is the maximum length of the stick...

In this thread in another forum, I calculated the coordinate speed of light as measured by a distant observer. As far as I understand it, the length contraction in GR is only in the radial direction, right? None tangent, correct? The time delay of light found, though, trying different examples...

If two clocks with observers attach to them move away from each with symmetrical acceleration, they will experience symmetrical time dilation, meaning they both see the rate of each other's clocks slow down relative to their own. However, if the acceleration is asymmetrical, the time dilation...

1: Does an observer, standing on the moon, see a brick, that is falling straight down, to contract? 2: Does an observer, standing on the moon, see a light pulse, that is falling straight down, to contract?

OK, I've found a great explanation of the derivation of the Lorentz transformation, with x' = γ [ x - v t ] t' = γ [ t - ( v / c2 ) x ] so if I take the other term as 0, there is x'( t = 0 ) = γ x t'( x = 0 ) = γ t but the problem is that the time dilation & length...

Homework Statement Two spaceships having rest length 100 m pass each other traveling opposite directions with a relative speed of 0.901 c As the front of the spaceships just cross, each pilot sets off a small flare at the back of her own ship, synchronized to the same instant (t=0 in her own...

Homework Statement Show that the length contraction deforms a sphere in motion to an oblate rotational ellipsoid whose volume decreases by a factor of γ (gamma) Homework Equations x=x'/γ v=4∏r^3/3 (volume for sphere) v=4∏(a^2)b/3 (volume for prolate and oblate spheroid) The...

hi sorry about my english. i am from france. i have a few questions about the image i have found in my schoolbook that i attached to this post. there is a light signal moving up and down and each time it reaches the upper mirror this is somehow detected. there are also two observers: one...

Can one detect length contraction due to general relativity? I.e does length/width/height change with distance to a gravitational centre? If so does the object get longer or shorter? I know this is the case with increasing speed in special relativity, but what about GR... If i went into...

An observer on Earth sees a meteor approaching rapidly, heading directly for the Earth's surface. At a certain instant, the Earth observer sees the meteor at 650m altitude. If the meteor is traveling at 0.92c, as recorded by an Earth radar, what would be the altitude as measured by the alien...

I have been wondering why the universe should behave in such a way. There is no obvious reason why gravity or speed should change the rate you travel through time or the relative distances, 1 second should be 1 second and 1 metre 1 metre whatever the strength of gravity or speed. The only...

Consider two observers in relative motion.At x'=0, t'=0, x=0, t=0. There's a box at distance x metres in the unprimed frame. Since the primed frame moves with a relative velocity v, he observes the length x to be contracted by a factor gamma. Does this imply that when the obsever in the unprimed...

Lets say I have 2 charged spheres that are connected by a spring and they are a distance d apart. The spring is made of a material that will not allow the charge to evenly distribute. And each sphere has the same charge q on it. Now I move with respect to this object and I should see the spring...

A space traveler is very happy to discover that after a long period of 1 g acceleration the measured distance to his destination has contracted substantially. At some point he begins to plan for reversing thrust... It come to him that if he reduces the relative speed between his craft and...

Homework Statement Hello, I have a question about length contraction transformation. In my textbook it looks like this: x_1=γ(x_1'+ut'), x_2=γ(x_2'+ut') If the coordinates of the two events are (x_1,t_1), (x_2, t_2) , why is t used instead of t_1and t_2? The second problem I have is with...

I have read somewhere about the phenomenon called gravitational length contraction.Was gravitational length contraction predicted by general theory of relativity?

Homework Statement Λ particle has a proper life-time τ = 2×10−10 s. After being born in the cloud chamber (a device to track energetic particles) of physics laboratory it left there a a 300cm long trail. Find the speed of this particle in the laboratory frame. Homework Equations...

This link is confusing me. http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/muon.html In this link, with non-relativistic method, half life is calculated as 21.8. But with relativistic method half life is calculated as 4.36. We calculate half life considering time dilation for muon...

A google search revealed an often asked question (including a locked thread here) about two ships approaching with closing speed > c, say each going .75c. And there's always multiple answers from the experts about relative frames and Lorentz this and that and you have to use the special formula...

The title isn't quite clear, because the question was a little too long. Here it is in full: How to apply length contraction and time dilation to a moving observer to measure the speed of light of a light beam moving parallel to their reference frame. Imagery and familiarity are my...

Hello, Suppose, There is two points [t_{a1}, x_{a1}] and [t_{a2}, x_{a2}] stationary in my frame A. I say L_a=x_{a2}-x_{a1}. If I want to find x component of co-ordinates in other frame B which is moving relative to me with constant speed v. I have to use the equation 1...

Is there any potential energy associated with length contraction? If I start with a rod at rest, and accelerate it to a relavsitic kinetic energy, the rod also length contracts, at least as viewed from the ground frame watching the rod go by. When the rod decelerates and comes to rest, it will...

Suppose there exists an absolute frame. The observer is at rest. an object moves with velocity v. Suppose it contracts as expected. Does this imply automatically that time dilation occurred?

To understand length contraction better, would an precise instrument where width, height and length must be exact equal for working when standing still in frame A, still working in its rest frame B at a higher speed in frame A with length contraction ? With other words, is length contraction...

It is my understanding that an astronaut could get from Earth to the far edge of the Milky Way within the length of a human lifetime if she were traveling close enough to the speed of light. From earth’s perspective, time would pass very slowly for her as she moved across the galaxy. From the...

Homework Statement An electron travels in an accelerator tube at a speed of 0.997 c relative to the Earth. In the frame of the electron, the length of the tube is 1.20 m. A. What is the length of the tube relative to Earth? B. Relative to Earth, how long does it take for the electron to...

For the explanation of the Lorentz derivation in Wiki with the known triangle, 2 rest frames are considered in 1 view, so that's not forbidden. So I do too. To explain time dilation is easier to understand if you see it by length contraction. That could be explained somehow in the future...

I've been told several times that length contraction is not "real" in the sense of material or its space actually contracting. How does modern physics (by that I mean what is being taught currently) view Bell's spaceship paradox. Will the string break? Why, if length contraction is not real...

There is a train(think of having only two boggie for a claer visualization ) in which two rod which are attached to the front and rear end of the train(say, the length between these rod is the length of the train). These are lowered by a single lever to touch the ground. These rods are at...

Homework Statement A rod of length L_0 moves with a speed v along the horizontal direction. The rod makes an angle of θ_0 with respect to the x'-axis. a. Show that the length of the rod as measured by a stationary observer is given by L = L_o [1 - (v^2 / c^2) cos^2 (θ_o) ]^(.5)...

Homework Statement Two events are observed by inertial observer Stampy to occur a spatial distance of 15 c·s apart with the spatial coordinate of the second larger than the spatial coordinate of the first. Stampy also determines that the second event occurred 17 s after the first. According...

The way I've been reading it, elliptic geometries are due to a positive Gaussian curvature, while hyperbolic geometries are due to a negative Gaussian curvature. Do local saddle curvatures mean local time dilation and length contraction, or do they mean local time acceleration and length...

How can relativistic length contraction be measured at the quantum scale? Since a Planck length by definition cannot be divided, how can something that is 1 Planck length, traveling near the speed of light, contract with respect to an observer? In other words, how can an observer possibly...

In this video: Special Relativity: Length contraction in more detail http://www.youtube.com/watch?v=s3ZqBt8KWVQ&feature=mfu_in_order&list=UL for the derivation of Lorentz contraction equation at 2.48 the guy says, "I won't bore you with the details". I'd appreciate is someone would...

Are these really just two ways of explaining the same thing?

This question is in regard to special relativity. From my rudimentary understanding, concerning the twin paradox, if one twin leaves traveling near the speed of light and returns, he will find himself younger than his twin who stayed behind. Hence, the effect of time dilation is permanent...

1 does length contraction occur in gravitational fields 2 what is the equation of gravitational length contraction 3 what are the units of measuring mass not weight

We all know the definition of a rope between two identical accelerating spaceships and how that rope will break assuming they both accelerate with the identical same velocity (as defined from a observer on Earth for example). And it makes sense, thinking of stress. But how do I define a Lorentz...

Homework Statement The dimensions of your friend’s spaceship are 100 meters in length, with a cabin width of 20 meters (i.e., you could approximate the main body of the ship as a cylinder with length 100 meters and diameter 20 meters). However, since your friend’s spaceship is speeding past...

Homework Statement A rod of proper length L0 oriented parallel to the x-axis moves with speed u along the x-axis in S. What is the length measured by an observer in S'? Homework Equations Relativistic relative velocity: For an object moving with speed u in S, its speed u' in S' = (u - v)/(1...

A clock falling towards the event horizon of a black hole would appear slowed down to the point of being frozen in time (or almost). But I'd like to understand properly what happens to the length contraction experienced by an observer falling together with that clock. Would he experience...

I'll try to be as specific as possible with my question. From my reading of SR I understand that an object that is moving relative to me will be contracted in the direction of its motion. I have no issue with that and I accept it as a fact. Would I be right in thinking that there is also length...