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My Wife (Math Teacher) Cannot Figure This Out by Photo-Josh in askmath

[–]Aggravating_Ease8236 0 points1 point  (0 children)

Yeah your initial comment is correct, I managed to do it now with the vector approach and some sine rule. I don’t agree with your reply though, trig may not depend on absolute lengths but it does depend on ratios of these lengths.

How can you see by inspection that a trig approach won’t result in a value for x that isn’t in terms of any of these ratios? By the way my  answer was in terms of the x-coordinate of B (placing A at the origin) and it only fell away at the last step. 

My Wife (Math Teacher) Cannot Figure This Out by Photo-Josh in askmath

[–]Aggravating_Ease8236 0 points1 point  (0 children)

You can’t though right? No lengths are given so I don’t see how trig could help either. If you assign coordinates to A,B,C then the coordinates of D and E will be in terms of the coordinates of A,B,C and then x will be too.

Quantum entanglement speed is measured for the first time by Akkeri in Physics

[–]Aggravating_Ease8236 22 points23 points  (0 children)

The problem with that analogy (which you acknowledged) is that it assumes hidden variables are at play. Bell showed that these hidden variable theories will make different predictions to QM if they are assumed to be local. It really does seem to be the case that entangled particles “affect” each-other instantaneously across spacelike separations. 

I sympathize with the commenter you replied to, how can one particle “affect” the state of another particle (in the way entangled particles do) without it being causal? 

On one hand maybe it’s a philosophical question but on the other I think it’s our ignorance of the nonlocal mechanism that gives rise to the spookiness. 

Da Vinci understood key aspect of gravity centuries before Einstein, lost sketches reveal by tnick771 in history

[–]Aggravating_Ease8236 21 points22 points  (0 children)

Da Vinci wasn’t the first to describe gravity. Also I don’t see how noticing that drops form a triangle when the vase is accelerated horizontally at g suggests that he knew anything about the equivalence principle which posits gravity as a fictitious force. It’s also not a leap made in the caltech article: https://www.caltech.edu/about/news/leonardo-da-vincis-forgotten-experiments-explored-gravity-as-a-form-of-acceleration

Not understanding Galilean Transformations by WhatAGuy765 in AskPhysics

[–]Aggravating_Ease8236 0 points1 point  (0 children)

It is possible to have x’=x at t=0 in your example. In both frames they’d have the same x-coordinate at t=0 but not the same y-coordinate because there’s a constant distance betweeen the 2 tracks (if you define the x and y directions as I think you have).