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How to explain Einstein's Special theory of Relativity. 
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#37
Dec912, 11:21 PM

P: 52

As I know, SR can be used for two systems with constant relative speed; however, in case of constant relative velocity SR should be correct as well. I mean, in cases of constant relative velocity, should I use LT or SR? Do you have website where I can find the answer of it? Thanks. 


#38
Dec912, 11:29 PM

P: 784

There is a lot in SR. The Lorentz Transformations were a set of coordinate transformations that Lorentz first developed with regards to electromagnetism. It was Einstein who first used them to describe space itself, and the time dilation and length contraction equations come directly from the lorentz transformations.
You keep saying that LT and SR are seemingly two distinct things, which is completely wrong. The Lorentz Transformations are a part of SR. To ask whether to use Special Relativity or the Lorentz Transformations is like to ask whether to use Newtonian Mechanics or Newton's Second Law; the question doesn't make sense. 


#39
Dec912, 11:37 PM

P: 52

Maybe if you gave me an example of what you consider to be an equation of SR and an equation of LT I would better understand your question. 


#40
Dec1012, 12:12 AM

PF Gold
P: 4,087

What difference do you think it makes ? 


#41
Dec1012, 06:14 AM

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#42
Dec1012, 06:47 AM

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#43
Dec1012, 08:04 AM

P: 52

That is the best answer I have received so far. Thanks. Do you mean, only when x'=0 we can use SR, otherwise, we should apply LT?



#44
Dec1012, 08:08 AM

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#45
Dec1012, 08:10 AM

P: 52




#46
Dec1012, 08:16 AM

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#47
Dec1012, 08:20 AM

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You seem to be using "SR" to mean the time dilation formula, which is a special case of the LT (as has been explained). Your nonstandard use of "SR" is creating some confusion. 


#48
Dec1012, 08:36 AM

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In this example, since the events in question all take place at x = 0, you can convert the time between them (Δt) to the moving frame (Δt') using the time dilation formula: Δt' = γΔt. But that's just an application of the LT. What's your point? 


#49
Dec1012, 08:57 AM

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You continue to identify SR with only the time dilation formula. That is simply WRONG. 


#50
Dec1012, 08:59 AM

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I think there is some language barrier. Perhaps this will help: [itex] SR \supset LT \supset time \; dilation [/itex] [itex] SR \neq time \; dilation[/itex] 


#51
Dec1012, 09:25 PM

P: 52

In above example, two systems have constant relative velocity so that the speed of time in the moving system t' and the speed of time in the stationary system t should be decided once we select the point O as the stationary point, and the O' as the moving point. Under this SPECIFIC arrangement, when we talk about a period of time for ONE SPECIFIC EVENT then we should have ONLY ONE event period Δt as recorded in the stationary system and ONLY ONE event period Δt' as recorded in the moving system. Now, what SR claims is Δt' = Δt/γ and what LT claims is Δt' = γΔt for the ABOVE example. Logically speaking, this should not happen UNLESS γ=1, isn't it? How do you explain this logical issue? If you like the event to stay in the moving system, then you may let x'=1. 


#52
Dec1012, 09:36 PM

P: 52




#53
Dec1012, 09:37 PM

P: 784

You are wrong with these equations. In both LT and SR (it seems stupid as I previously mentioned to distinguish between the two like that but I'll cave for argument's sake), ##\Delta t'=\Delta t \gamma##. You may be confusing the time dilation equation with the length contraction equation, which is ##\Delta L'= \frac{\Delta L}{\gamma}##



#54
Dec1012, 09:47 PM

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P: 41,438

Events that happen at x = 0 can be treated similar to a clock at that point that is stationary in the unprimed frame. From the primed frame, that clock is moving and obeys the 'time dilation' formula (which is derived from the LT). You'll get Δt' = γΔt no matter how you slice it. 


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