Recent content by john t

Then this disqualifies me from using the forum. I am legally blind, and use of LaTex is beyond my ability. (I installed it on my mac, and see that it is beyond me.) The keystrokes are just too difficult. I am able to use MathType, but you guys do not recognize that apparently. Maybe I can...

Thanks Nugatory. I understand, and I do not think you are quibbling, and your analogy with the Lorenz situation makes the point clear. Can one say that my logic shows the consistency of the specific with the general equation, given the acceptance (naieve?) of relativistic mass?

Thanks, Nugatory. I would like to know what math or physics principle was broken. There is a derivation of E=gamma mc^2 based on thought experiments and that admittedly requires the assumption of non-zero mass. Is the objection that my approach goes from a specific to a general equation? In...

The way I rationalize it requires recognition of relativistic mass and thus momentum and starts with E=gamma mc^2. My algebra is attached as a screenshot.

Thanks, Kurman, Ibix et. al. Once I gathered the t^2 and x^2 terms I got to the result. Instead of 3 steps it took me about 9 - guess that's why I am a chemist and not a physicist.

Thanks. The identity you wrote is an obvious one, but it does not help me understand the path to the last equation. If the full article would help you do so here is the url - https://web.stanford.edu/~oas/SI/SRGR/notes/srHarris.pdf I am just a 76 year old legally blind guy trying to fill in...

In Phillip Harris' (U. Sussex) post on special relativity he includes on p. 45 an algebraic proof of invariance of spacetime intervals. He starts with the definition S^2 =c^t^2 - x^2 -y^2 -z^2, he inserts the Lorentz transform expressions fot t and x, and he does some algebra to show that one...

Thank you very much vanhees71. The matrix inversion will do it.

Thanks Ibix. Yes I know how to solve simultaneous equations, but I am still having difficulty. What 2 equations do you refer to? The original 2 equations do not both have x' in them, so I cannot see how one eliminates it. I guess the common-sense answer to my question is to consider that...

I attached my efforts as a pdf of my work in the mac program called Notes. At the top I show the transforms giving x' and t' on the left (the derivations of whch I understand) and the desired inversions on the right. Under the line on the left I show my work, which then shifts over to the...

Thanks, but LaTex is not working as its instructions say, and I downloading of mactex was disallowed on my mac. Could I put my work in a word document using MathType for eqns and paste the doc in reply. I have severe glaucoma and have trouble sorting these things out on my mac.

How are the Lorentz transforms inverted from x' = gamma(x -vt) and t' =gamma(t - vx/c^2) to the equations x =gamma(x'+vt') and t = gamma(t'+ vx'/c^2) ? The closest explanation I have seen on line is to change the non-primes to primes and reverse the direction of v). But what is the algebra...

I posted this earlier, but the thread has been closed. String theorists frame much of their studies in the context of Planck length. The theories are meant to fold together QM and general relativity. The equation for Planck length includes the gravitational constant, G. It seems to me the...

Brian Greene, in his book "The Elegant Universe" couches all the arguments around the Planck Length. He is a physicist/mathematician at Columbia U.

String theorists frame much of their studies in the context of Planck length. The theories are meant to fold together QM and general relativity. The equation for Planck length includes the gravitational constant, G. It seems to me the theorists are assuming the gravitational laws extend to...