# Homework Help: Relativity , R. Shaw paradox

1. Sep 11, 2008

### briteliner

1. The problem statement, all variables and given/known data

A very thin steel plate with a circular hole m

1 in diameter centered
on the y axis lies parallel to the xz plane in frame S and moves in the +y
direction at a constant speed y
v (as illustrated in Figure 1-44 of the text).
A meterstick lying on the x axis moves in the +x direction with c
v/
=
β .
The steel plate arrives at the 0
=
y plane at the same instant that the
center of the meterstick reaches the origin of S. Since the meterstick is
observed by observers in S to be contracted, it passes through the m

1
hole in the plate with no problem. A paradox appears to arise when one
considers that an observer in S′, the rest system of the meterstick,
measures the diameter of the hole in the plate to be contracted in the x
dimension and, hence, becomes too small to pass the meterstick,
resulting in a collision. Resolve the paradox. Will there be a collision?