According to Special Relativity, which ones are dependent on the observer speed?
Q. Consider the list of physical properties below. According to Special Relativity, which ones are dependent on the observer speed? Energy Length Time All of the these.
Asked by stephie - Wed Jul 23 10:50:44 2008 - - 4 Answers - 0 Comments

A. all of these
Answered by Andrew B - Thu Jul 24 21:38:34 2008

Why does special relativity say that c is constant?
Q. As I understand it, special relativity says that all the laws of electromagnetism are the same for observers in all reference points. I also know that this is why the speed of light remains the same for all observers. But what law of electromagnetism states, or predicts, that light has to be exactly the speed it is? I think it has something to do with Maxwell's equations, but I've not been able to connect the dots. Can someone explain in a non-technical way why the speed of light specifically is one of the laws that remains the same for all observers?
Asked by Leon M - Mon Jun 2 23:31:57 2008 - - 6 Answers - 0 Comments

A. First: That's special relativity, which deals with non-accelerating inertial reference frames. NOT every reference frame, you need general relativity for that. With that in mind... There's a couple of logical roads to go down here Maxwell's equations imply that the speed of light is c in a vacuum. You generally think of waves as propagating through something, like sound waves propagate through matter. Take away the matter and they don't, hence no sound in the vacuum of space. Maxwell's equations don't say anything about reference frames, basically if you have a changing electric or magnetic field, you get a transverse wave traveling at c. So just from Maxwell's equations alone there are two conclusions. One is that it means c… [cont.]
Answered by Matty - Mon Jun 2 23:42:32 2008

How did Einstein come up with the theory of special relativity based on then current scientific knowledge?
Q. Did he guess or was there some logical technique he used. Did he use the scientific method. I understand that they are just now proving some of his theory with evidence. I am most interested in his thought process. Did he ever describe how he thought up the special relativity?
Asked by M O - Mon Mar 2 20:30:12 2009 - - 2 Answers - 0 Comments

A. Yes Einstein was famous for creating straightforward "thought experiments" or "gedunken experiments". Before Einstein theorized special relativity a scientist named Maxwell proved that electricity and magnetism are actually different formulations of the same force, "sense" this force by electromagnetic radiation (light). Maxwell proved that the speed of light never changed. Einstein considered this a contradiction of modern theory his thought experiment was essentially: If you were on a train and you emitted a beam of light wouldn't the light be moving faster than the accepted "speed of light" to an observer that is stationary since you add the speeds (speed of train+speed of light). You can think of throwing a baseball on a train, to… [cont.]
Answered by Jon - Mon Mar 2 20:43:55 2009

How can special relativity be generalized?
Q. And what whould be an explanation when special relativity is generalized?
Asked by goring - Wed Sep 6 12:14:15 2006 - - 3 Answers - 0 Comments

A. Were you to read an easy to read, short paper "The Problem and Repair of Relativity" at you will understand the basis of relativity concepts. I would post it here, but it is rather too long for that.
Answered by noddarc - Wed Sep 6 12:53:04 2006

If Einstein disproved Aether with Special Relativity, doesn't that contradict with him discovering dark energy?
Q. Einstein disproved Aether with special relativity when he discovered that light waves don't need to propagate through any medium. But, If Aether and "Quintessence" are the same and "Quintessence" is a form of dark energy, How is it that he disproved Aether, when he is said to be the one who 'discovered' dark energy and the accelerating expansion of the universe? And what exactly is the difference between Dark energy and dark matter?
Asked by puffalump - Mon Jul 20 17:37:20 2009 - - 4 Answers - 0 Comments

A. Dark energy is the name given to the missing energy that we can't see or explain which must exist in order for the universe to be expanding at its current rate. It doesn't necessarily exist. But, if we don't find it, it means we have to go back to the drawing board on some rather basic ideas. Dark matter is the matter we can't see or detect that must exist in order for galaxies to have the shape and rotational speed they do without stars flying away, and to account for "missing matter" that big bang models predict. Neither of these really contradicts the lack of aether. Aether wasn't about adding missing energy or mass, but rather providing a medium for the apparent wave action of light. Also, dark matter and energy don't necessarily… [cont.]
Answered by Bill - Mon Jul 20 17:57:00 2009

What is physical basis of Length Contraction in special relativity?
Q. Einstein's theory of special relativity says that the length of an object such as a space ship moving at relativistic speeds undergoes a contraction along the dimension of motion. An observer at rest would observe the moving object to be shorter in length.How this works. What happens to physical properties of the object that it becomes shorter. why it contracts only in context of stationary reference frame and is there any empirical evidence in support of this theory?
Asked by Phil - Tue Sep 15 11:11:27 2009 - - 3 Answers - 0 Comments

A. The length contraction does not reflect any changes at all to the physical properties of the object. At one time (before the theory of relativity was accepted), there was a hypothesis that things contracted due to a physical interaction with the so-called "luminiferous ether" as they traveled through it; but this idea (along with the ether itself) was discarded in favor of relativity. Relativity predicts that time intervals and distance intervals are relative, not absolute; and today we interpret length contraction as simply a manifestation of the relativity of distance measurements. To put it more concretely: Consider how we'd measure the length of a passing space ship. We would record two events: say, "Event 1" is when the ship's… [cont.]
Answered by RickB - Tue Sep 15 11:43:31 2009

Which of the following is a postulate of Special Relativity?
Q. Which of the following is a postulate of Special Relativity? The color of light is the same for all observers. The laws of physics are the same for all observers in uniformly moving frames of reference. The relative speed of two objects is the same for all observers. Physicists can make no measurements in a moving reference frame.
Asked by stephie - Wed Jul 23 10:43:01 2008 - - 3 Answers - 0 Comments

A. The laws of physics are the same for all observers in uniformly moving frames of reference. = TRUE, this is the actual postulate. General relativity goes even further and removes the "uniformly moving" clause. The color of light is the same for all observers. = false: the color of light changes according to the relativistic Doppler effect. The relative speed of two objects is the same for all observers. = false. It's true in Newton's theory, but the formulas of SR say it doesn't hold exactly and ceases to work at all when the speeds get comparable with the speed of light. Physicists can make no measurements in a moving reference frame. = false, an absolute nonsense. How could you then, for example, measure your speed when driving a car?… [cont.]
Answered by Va ek - Wed Jul 23 17:19:31 2008

Could anybody offer a website that fully explains general/special relativity?
Q. I understand matrices/inverse matrices completely, but I'm only in Algebra II so I'm not sure the entire mathematical explanation would be plausible. However, any websites in plain English that would fully explain general/special relativity and other correlating concepts? (: Thank you in advance.
Asked by Caty S - Fri Apr 4 21:54:21 2008 - - 3 Answers - 0 Comments

A. If you've got some time, this is a link to Einstein's own book on the subject, which is the eminent source on the topic, because it is presented from the prospective of a plausibility argument which is then completed with math.
Answered by planck6626 - Fri Apr 4 22:20:38 2008

hard question implications of the postulates of special relativity?
Q. Einstein performed thought experiments to understand the implications of the postulates of special relativity because... he was too poor to afford the necessary experimental apparatus. he could not carry out the experiments alone and no other scientists would work with him. did not know how to build an apparatus that would test his ideas. the speeds involved are too large to easily generate.
Asked by stephie - Tue Jul 29 12:39:58 2008 - - 4 Answers - 0 Comments

A. The last one. Although the second to last is also true I think the last one is a slightly clearer answer.
Answered by Barto S - Tue Jul 29 12:47:12 2008

Original Text of Einsteins Theory of Special Relativity?
Q. Does anyone know of a website that has the original text of Einstein's 1905 paper on Special Relativity?
Asked by Brandon C - Sun Sep 2 15:32:58 2007 - - 1 Answers - 0 Comments

A. Here are some... Enjoy ^_^
Answered by Calculus - Sun Sep 2 15:41:31 2007

how did Einstein come up with the theory of special relativity?
Q. how did eintstein come about the theory of relativity? and can you please simply describe what this is?
Asked by I don't Know - Mon Sep 21 18:55:52 2009 - - 1 Answers - 0 Comments

A. Basically, he got curious. The "Principle of Relativity" is as old as Gallileo. It is the idea that the laws of physics should be the same for all observers (regardless of any relative motion between them). When it was proven that the speed of light is always the same for all observers (regardless of any relative motion between the light source and the observer,) Einstein began to wonder. Are those two ideas really compatible? What would the laws of the Universe be like if they both were true? Special relativity is pure math. He arrived at it by simple deductive reasoning based on the known laws of physics and those two ideas. The resulting theory is too complex for me to describe here, but you can read about it in his own words. … [cont.]
Answered by pzifisssh - Wed Sep 23 11:05:10 2009

Another question about Einstein's theory of special relativity...?
Q. I know that a consequence of relativity is time dilation. I can understand how this works with events and such, since most events relate to light or some process such as electricity. I've heard of experiments where planes have traveled really fast and recorded time dilations with atomic clocks. This makes sense. But I also read that it works with biological processes too. Can someone explain how this works. I don't understand how the biology of the human body is related to light, electromagnetism, gravity, or the physics of special relativity.
Asked by Josh C - Sat May 31 14:48:42 2008 - - 4 Answers - 0 Comments

A. Relativistic length contraction makes the orbits of electrons elliptical and the electrons take longer to go around the nucleus. Therefore, chemical processes are slower, and biology is a matter of chemistry.
Answered by Philip J - Sat May 31 15:33:05 2008

How does special relativity deal with this?
Q. If you have a wheel and axle, and by some means you spin the axle at the speed of light, what would happen to the wheel, whose outer rim is traveling faster? This is all rhetorically, of course-I know there is no way of doing this.
Asked by Quantum_paradox - Wed Mar 5 23:54:07 2008 - - 3 Answers - 0 Comments

A. You already answered the question - special relativity basically deals with it by saying "You can't get there from here". To accelerate the wheel so it's outer edge is moving at the speed of light would require an infinite amount of power, which can't happen. Now, if you want an interesting problem, work out what happens to the wheel when it's *nearly* at the speed of light, due to the different speeds at different radii - at normal speeds, the wheel turns as one piece, but once you get relativistic, you get all sorts of foreshortening issues and so on, so the apparent circumference at one distance out isn't half the circumference twice further out...
Answered by Valdis K - Wed Mar 5 23:59:55 2008

Which of the following assumptions causes the classic relativity to fail and reguires a special relativity?
Q. a. the law of physics is the same for everybody b. the speed of light is te same for everybody c. the sequence of event observed should be in the same order for everybody d. the universe is finite in extent e. all laws are relative, especially for me. I chose B..any other answers?
Asked by Stacey L - Thu Apr 10 19:34:25 2008 - - 1 Answers - 0 Comments

A. B is actually the reason why Einstein (and a few others before him) tried to find a better relativity rule. The 'classical' relativity is also called Newtonian relativity (or even Galilean relativity). Under classical relativity, when you had A's speed relative to B and B's speed relative to C, you simply added to find A's speed relative to C. However, when radio waves were discovered, it was found that radio waves always traveled at the same speed, whether they were sent by a fixed land station or a moving transmitter. It was easy enough to measure the speed of radio waves that even small differences should have been detected. At about the same time, Maxwell showed that light and radio were simply two manifestations of the same thing: [cont.]
Answered by Raymond - Thu Apr 10 19:52:59 2008

Are there any experiments which test special relativity?
Q. I know of the Kennedy Thorndike experiment, but it involves light. I am curious whether a different kind of experiments showing relativistic effects like time dilation or length contraction have been performed (I'm thinking of experiments involving mechanical devices like mechanic clocks, rather than light clocks). If there are none, why should we accept that relativistic effects occur for other kinds of moving devices (like mechanical clocks), besides those using light (like light clocks). I'm not questioning SR, I just don't know the answer.
Asked by quantum - Sat Nov 18 13:09:23 2006 - - 6 Answers - 0 Comments

A. My techer said that scientists had 2 clocks that were accurate to like, nano-second, or more, and put one on a plane and flew it aorund the world and when it landed it was different than the other which didnt move
Answered by koldsauce12 - Sat Nov 18 15:15:28 2006

How special relativity is applied in GPS?
Q. Any information will be greatly appreciated. Also, if you can point any web pages about the subject, extra points.
Asked by Rob - Tue Jan 20 10:02:47 2009 - - 1 Answers - 3 Comments

A. All about the clock synchronizations ; in case of GPS we dealing with long distances and high speeds of satellites(), the time precision needed for position trangulations must be in tact due to high resolution of system... then need to use relativity correction, to calculate signal delays (time/distance dilatations )...
Answered by Paul - Tue Jan 20 10:12:37 2009

According to special relativity, events that are simultaneous in one reference frame?
Q. 1.) Arent simultaneous in other frames of reference 2.) may not be simultaneous in other frames of reference 3.) are simultaneous in other frames of reference
Asked by Liam S - Thu May 1 19:35:16 2008 - - 2 Answers - 0 Comments

A. 2.) may not be simultaneous in other frames of reference Draw a line segment AB connecting the positions of two events A and B that are simultaneous in frame x Consider a frame x1 moving (as viewed in frame x ) along AB from A to B. In frame x1 AB will be viewed as moving with A at the leading end and B at the trailing end. In this frame x1 the trailing event B happens first. Consider a frame x2 moving (as viewed in frame x ) along AB from B to A. In frame x2 AB will be viewed as moving with B at the leading end and A at the trailing end. In this frame x2 the trailing event A happens first. Consider a frame x3 moving (as viewed in frame x )perpendicular to AB at its mid point In frame x3 AB will be viewed as moving toward it… [cont.]
Answered by shawn s - Thu May 1 20:23:12 2008

Can someone explain how this situation works in special relativity?
Q. OK, so let's say there's twin brothers, Al and Bert. Let's say Al goes off in a rocket at .9c away from Bert for two years of Bert's time. When Al comes back, he'll be younger than Bert is. I'm fine with that. But now let's say that Al stays put and Bert shoots off in the opposite direction at .9c for two years of his time. Wouldn't Bert, when he comes back from his trip, be younger than Al? But aren't the two situations exactly the same (since velocity is relative)? Obviously, they can't both be younger than the other brother.
Asked by Kevin S - Fri May 22 14:29:07 2009 - - 3 Answers - 0 Comments

A. ADDED: sorry, I misread your question. The answer is that whoever is travelling will get younger. So Al will be younger than Bert when he gets back, and then Bert goes away and ages less than Al and comes back. their difference in ages will depend on who has travelled further and quicker. If they travelled at the same speed and for the same distance, they'll be the same age again :) ... but are you sure that's what you mean to ask? because there is a very famnous paradox called 'the twin paradox', composed by Einstein, which is based on what you say. imagine Al goes off for his trip and comes back younger. But can't Bert claim, well velocity is relative, so shouldn't Bert also be younger? (There is no second trip involved in the twin… [cont.]
Answered by Dr Octavian - Fri May 22 14:34:52 2009

What are the two predictions of special relativity that have been tested and found to be correct?
Q. What are the two predictions of special relativity that have been tested and found to be correct?
Asked by Alicia - Wed May 6 09:51:26 2009 - - 1 Answers - 0 Comments

A. Time dilation (as we said in the other question): --GPS clocks run a little slower because they are moving (although they also run faster because they are higher up in the gravitational field) --Unstable particles last longer in motion than they do at rest Relativistic relation of energy and speed and mass. E = mc^2 / sqrt (1 - (v/c)^2) --As a particle approaches the speed of light, it's energy goes up towards infinity. We see this in particle accelerators all the time. You can give a particle more and more and more energy, and its speed just gets the tiniest bit closer and closer and closer to c. --A particle at rest has energy which is proportional to its mass. Nuclear physicists use this to keep track of the energy in nuclear… [cont.]
Answered by ( )Mistress Bekki - Wed May 6 09:54:12 2009

According to the special theory of relativity, physical laws are the same in frames of reference which?
Q. According to the special theory of relativity, physical laws are the same in frames of reference which ... accelerate. move at uniform velocity. move in ellipses. move in circles.
Asked by stephie - Tue Jul 29 12:25:03 2008 - - 2 Answers - 0 Comments

A. move at uniform velocity
Answered by bravozulu - Tue Jul 29 12:32:35 2008