Insights Introducing Relativity on Rotated Graph Paper: A Graphical Motivation

robphy
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(based on https://www.physicsforums.com/threads/teaching-sr-without-simultaneity.1011051/post-6588952 and https://physics.stackexchange.com/a/689291/148184 )

In my earlier Insight Spacetime Diagrams of Light Clocks,
I stated without proof that the areas of all light-clock diamonds are equal.
In my article, “Relativity on Rotated Graph Paper”, Am. J. Phys. 84, 344 (2016)
I provided algebraic proof.

In the penultimate draft, I had a non-algebraic motivating argument (which also motivates time dilation and length contraction)
that had to be left out because the article was already too long.
This argument now appears in Introducing relativity on rotated graph paper...

Continue reading...
 

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So, to calculate a proper time of a worldline in SR using an inertial frame is quite easy. But I struggled a bit using a "rotating frame metric" and now I'm not sure whether I'll do it right. Couls someone point me in the right direction? "What have you tried?" Well, trying to help truly absolute layppl with some variation of a "Circular Twin Paradox" not using an inertial frame of reference for whatevere reason. I thought it would be a bit of a challenge so I made a derivation or...
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