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- Thread starter NiallBucks
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In summary: I did not memorize a single formulae. I just used the invariance of the interval. You can do the same.In summary, the conversation discusses the use of Lorentz transformations and Time dilation and Length contraction equations in solving problems related to special relativity. While some suggest using only the Lorentz transformation, others argue that using both methods can provide a better understanding of relativity. It is also mentioned that the relativity of simultaneity cannot be solved using time dilation and length contraction alone. Finally, one person claims to have solved all problems using only time dilation and length contraction, even in their studies of general relativity.

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A rocket passes the Earth at v=0.6c and both the rocket and Earth agree it's 12:00. At t'=13:00 the rocket passes a space station. Show that the rocket passes the space station at 13:15 in the Earth's frame.

Here γ=5/4

Which would I use here? Is it correct to say T=γTo so then if you sub To as 1 you'll get 1.25 which is an hour and a quarter (ie 13:15) or am I misunderstanding something?

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NiallBucks said:

Why not do both? Two different solutions to a problem that agree are better than one!

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NiallBucks said:

A rocket passes the Earth at v=0.6c and both the rocket and Earth agree it's 12:00. At t'=13:00 the rocket passes a space station. Show that the rocket passes the space station at 13:15 in the Earth's frame.

Here γ=5/4

Which would I use here? Is it correct to say T=γTo so then if you sub To as 1 you'll get 1.25 which is an hour and a quarter (ie 13:15) or am I misunderstanding something?

The perfect example! Do it both ways and check you get the same answer.

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No, not at all. The Lorentz transformation is more fundamental in SR than time dilation and length contraction. You will only run into conceptual issues if you think otherwise.MachPrincipe said:If you do so, you will gain a much deeper understanding of relativity.

It might seem easy to work your way through some problems without using the full Lorentz transformation, but you'll most definitely run into hot water if you try solving anything different from those "standard" relativity questions using the TD and LC formulae only.MachPrincipe said:With practice either method will be as easy as the other.

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I completely disagree with this. Time dilation and length contraction alone cannot be used to solve problems involving the relativity of simultaneity. If your physics 101 course did not include exercises on the relativity of simultaneity then it was not enough of a curriculum to even be considered an introduction to relativity.MachPrincipe said:

That is an indication of a deficiency in the course, not an indication of the sufficiency of length contraction and time dilation.

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The course was relativdly good :) It was me who didn't want to use the Lorentz transf. after understanding them. The problems included the barn and pole apparent paradox, and I solved with time dilation and length contraction alone. As said, you only need to take into account the travel time of light rays, which is the faster way of communicating events, and what lies beneath the reason of the relativity of simultaneity (Einstein original paper).DaleSpam said:I completely disagree with this. Time dilation and length contraction alone cannot be used to solve problems involving the relativity of simultaneity. If your physics 101 course did not include exercises on the relativity of simultaneity then it was not enough of a curriculum to even be considered an introduction to relativity.

That is an indication of a deficiency in the course, not an indication of the sufficiency of length contraction and time dilation.

I have studied GR at the faculty, and no need of using Lorentz transform. never in my life. Why the academical books insist on this historical and rather artificial approach is beyond my understanding.

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I doubt it.MachPrincipe said:I have studied GR at the faculty, and no need of using Lorentz transform

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You can take my word. As for special relativity, think of a problem and send me a message or post it here. I will use time dilation and length contraction formulaae alone. It is funny. Even with cuadrivector p_i , E... I solved by this method though they wefe a little harder.PWiz said:I doubt it.

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Does your knowledge of SR extend to 4-vectors and energy/momentum transformations?MachPrincipe said:You can take my word. As for special relativity, think of a problem and send me a message or post it here. I will use time dilation and length contraction formulaae alone. It is funny. Even with cuadrivector p_i , E... I solved by this method though they wefe a little harder.

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PeroK said:Does your knowledge of SR extend to 4-vectors and energy/momentum transformations?

PeroK said:Does your knowledge of SR extend to 4-vectors and energy/momentum transformations?

Physcis 101,-introduction to. SR.

Quantum physics - SR with attention to particle physics, matter-antimatter aniquilation, Compton effect, Thomas precession.

General Relativity as a semester included in Astrophysics subject.

Analytical Mechanics and Relativity.

And yes, I solved (E,pc) problems by using time dilation and length contraction relationships. Very funny and very useful to understand relativity.

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Physcis 101,-introduction to. SR.PeroK said:Does your knowledge of SR extend to 4-vectors and energy/momentum transformations?

Quantum physics - SR with attention to particle physics, matter-antimatter annihilation, Compton effect, Thomas precession.

General Relativity as a semester included in Astrophysics subject.

Analytical Mechanics and Relativity.

And yes, I solved (E,pc) problems by using time dilation and length contraction relationships. Very funny and very useful to understand relativity.

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MachPrincipe said:The problems included the barn and pole apparent paradox, and I solved with time dilation and length contraction alone. As said, you only need to take into account the travel time of light rays, which is the faster way of communicating events, and what lies beneath the reason of the relativity of simultaneity (Einstein original paper).

This just sounds wrong.

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That would be energy dilation and momentum contraction then!MachPrincipe said:Physcis 101,-introduction to. SR.

Quantum physics - SR with attention to particle physics, matter-antimatter aniquilation, Compton effect, Thomas precession.

General Relativity as a semester included in Astrophysics subject.

Analytical Mechanics and Relativity.

And yes, I solved (E,pc) problems by using time dilation and length contraction relationships. Very funny and very useful to understand relativity.

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Haha... Nobel prize for me, then. :)PeroK said:That would be energy dilation and momentum contraction then!

You can make p = mv. E = mc^2. m=m_0 * gamma.

Now you just get the v' for a particle and you are done. For v' you could use velocity transfor. formulae, but I didn't myself to use Lorentz, can be done

.with v=x/t alone for constant speed. Just think a little: it is just «low level Relativity».

s

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I'm curious as to how you can use that formula without acknowledging the fact that you're utilizing the Lorentz transformation.MachPrincipe said:you could use velocity transfor. formulae,

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Keep reading til the end of my sentence: just because I din't allow myself to use Lorentz, I did use v=e/t or the differential relationship.PWiz said:I'm curious as to how you can use that formula without acknowledging the fact that you're utilizing the Lorentz transformation.

Just choose any SR problem, send it to me, and allow for aboutp 24 hours so I s

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More importantly for the purposes of this forum,MachPrincipe said:Just choose any SR problem,

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http://scitation.aip.org/content/aapt/journal/ajp/51/12/10.1119/1.13322DaleSpam said:More importantly for the purposes of this forum,please provide a professional referencethat supports/explains your claim because the way you are explaining it does not make any sense.

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This citation does NOT support anything even remotely like what you have suggested. It does not use length contraction and time dilation in place of the Lorentz transform as you have proposed above. It also makes no claim that the method is applicable to all problems.MachPrincipe said:

Lorentz Transformations are mathematical equations used in special relativity to describe the relationship between space and time in different reference frames. They were first developed by Dutch physicist Hendrik Lorentz in the late 19th century.

Time dilation is a phenomenon in which time appears to pass slower for objects moving at high speeds. This is a consequence of the theory of special relativity, which states that time is relative and can be affected by the speed of an object.

Length contraction is the phenomenon in which an object appears shorter when it is moving at high speeds. This is due to the fact that space and time are interconnected and can be affected by an object's velocity.

Lorentz Transformations have many practical applications, such as in GPS technology, particle accelerators, and the study of high-speed particles. They are also essential in understanding the effects of time and space in special relativity.

Lorentz Transformations are a more accurate and comprehensive mathematical model than Galilean Transformations. They take into account the effects of relativity, while Galilean Transformations assume that time and space are absolute and independent of an observer's frame of reference.

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