The Effects of Relativity on a Bulb Setup

[anantchowdhary]

The following diagram is of a setup consisting of
A bulb
A pair of wires...making an angle theta with the place the bulb lies in


now if the setup is seen by an observer moving at a speed 'v' relative

the angle the wires make with the plane changes to phi>theta(i can provide the equations to prove this if needed...i might hav gone wrong...but I've cheked it so far..)

Now to the observer moving relative to the setup...the wires make a different angle...so what does that observer see?


does he see the bulb giving off light..if he does..then from his point of view...there is no energy being provided ..so how does the bulb provide light...

http://www.freeimagehosting.net/uploads/fcf29f98a3.jpg

 

[cesiumfrog]

Those equations should also show that the bulb is now closer to the battery..

 

[anantchowdhary]

Even though..theyr closer...wouldnt the width of the cavity containing the battry also contract...slo it wudnt make a difference...also the bulb's width would contract..

 

[anantchowdhary]

please help!

 

[Doc Al]

All linear dimensions along the direction of motion will "appear" contracted from the moving frame. Why do you think that that somehow implies that contact will be broken?

 

[JesseM]

If you draw a right triangle with the wires as the hypotenuse, only the horizontal side of the triangle (the base) will be shrunk by length contraction, and it will be shrunk by exactly the same factor as the distance from the battery to the base of the bulb, so naturally the wires will still be in contact with the bulb. Different reference frames never disagree on local physical facts like whether two objects touch!

 

[anantchowdhary]

but what about the change in the angle theta?

 

[Doc Al]

but what about the change in the angle theta?

What about it? Think of a ladder leaning against a wall at some angle. "Viewed" from a moving frame, the distance between the bottom of the ladder and the wall will be contracted. Of course it also appears to have a different angle with respect to the wall. (It better!)

Everything (triangles included) "appears" narrower along the direction of motion.

 

[anantchowdhary]

hmm...thnx..im getting it...

thnx a lot