- #1
Waxbear
- 42
- 0
I have two metal bars positioned in space so that, when viewed in the xy-plane, they intersect each other at some point P.
One of the rods are parallel with the x-axis and at rest, while i move the other rod downwards, in the -y direction, with a speed u. The speed of the point P, called U_P, should then be u/Tan(Theta). Since i can choose Theta to be as small as i like, i can make P move at a speed greater than light, and thus having made U_P > c.
I then stand at one end of the rod at rest and manipulate the rods like mentioned above, and my friend is standing on the other end of the rod at rest and sees the intersection arrive. Now consider that, before the experiment, i told my friend that when he sees the intersection arrive, it means "go!". Haven't i then sent the go-code to him at a speed faster than light, and thus transmitted an information carrying signal at a speed faster than light?
Of course i know that i haven't because SR doesn't allow this. But what part of the thought experiment is wrong?
One of the rods are parallel with the x-axis and at rest, while i move the other rod downwards, in the -y direction, with a speed u. The speed of the point P, called U_P, should then be u/Tan(Theta). Since i can choose Theta to be as small as i like, i can make P move at a speed greater than light, and thus having made U_P > c.
I then stand at one end of the rod at rest and manipulate the rods like mentioned above, and my friend is standing on the other end of the rod at rest and sees the intersection arrive. Now consider that, before the experiment, i told my friend that when he sees the intersection arrive, it means "go!". Haven't i then sent the go-code to him at a speed faster than light, and thus transmitted an information carrying signal at a speed faster than light?
Of course i know that i haven't because SR doesn't allow this. But what part of the thought experiment is wrong?