Will there be a collision?

[mntb]

A very thin steel plate with a circular hole one meter in diameter centered on the y axis lies parallel to the xz plane in frame S and moves in the +y direction at constant speed v, a mterstick lying on the x axis moves in the x directoin with v/c.The steel plate arrives at the y=0 plane at the same instant teh center of the meterstick reaches the origin of S. Will there be a collision?

 

[HallsofIvy]

Not all that paradoxical. The steel plate (more specifically, the hole) moves in the y-direction so there is no relativistic change in the diameter of the hole. The meter stick is moving in the x direction so there is contraction. By the way, (although it doesn't affect the answer) are you sure about that "with v/c"? Was that "with speed v/c"? In that case, what are the units?

 

[mntb]

yeah, but if you see it in the meter stick' coordinate, then the steel plate does have a relativisic change: it moves in the x direction