some questions (1 Viewer)

[clever angel]

hi evryone!

i am really confused on the simultaneity thought experiment- does the observer outside the train see lightning strike the front door of the train before the back door or vice versa?


q2: if a superconductor is above the critical temperature and a magnet is brought close to it wat will happen , is it like lenz law and repelling eddy currents

ne help is appreciated asapppp

 

[batigol]

for ur q2, i dun think anything will happen, say, if its a metal then the magnet will attract to it, if its made of ceramic then it will have no effect. u mentioned lenz law, the meissner effect is a result of lenz law, thats why eddy currents are induced to repel the external magnetic field.

 

[serge]

if a superconductor is above the critical temperature

It has to be BELOW the critical temperature
to show superconducting properties, like
Meissner effect, 0 resistance...

 

[serge]

i am really confused on the simultaneity thought experiment- does the observer outside the train see lightning strike the front door of the train before the back door or vice versa?

you brought up a really specific example

My example is two flashes going off simultaneously for a stationary person
equidistant from both flashes... this is simultaneous to them because
the speed of light is constant

however for an alien in a realitavistic spaceship, travelling from 1 flash to the other (lets just say he's half way when they go off)
the flash that he has already passed takes longer to reach him, than the flash
that he's travelling towards, hence for the moving observer the event
is NOT simultaneous

I hope this can apply to your train gedanken

 

[LostAuzzie]

My example is two flashes going off simultaneously for a stationary person
equidistant from both flashes... this is simultaneous to them because
the speed of light is constant
I hope this can apply to your train gedanken

Its essentially the same anyway, just replace the spaceship with a train and the flashes with lightning strikes.

I think Einstein's thought experiment on simultaneity used lightning strikes and a train, Einstein loved his trains

 

[helper]

It depends on the starting position of the train and motion of the train in your though experiment.

Have a look at this link
http://www.phys.unsw.edu.au/einsteinlight/jw/module4_time_dilation.htm#simultaneity

 

[sunjet]

q1. observer outside see's it at the same time
q2. meissner effect, the magnet above the superconductor creates eddy currents on the surface of the superconductor, which creates magnetic field which balances out the external magnetic field (lenz's law), thus allowing the magnet to hover above the superconductor as long as it stays below its critical temperature.

 

[helper]

The observer outside will not see it as simultaneous, that is why it is called the relativity of simualtaneity. Two simultaneous events observed in one frame will not be observed to be simulataneous in all other frames.