There are 2 identical 1m rulers (same rest length), and one if going past the other at some velocity. Each ruler has a clock every 10 cm. According to the fixed clock, the moving ruler's clocks will appear to be moving slow, and out of sync. (if t=0 when the rulers pass each other, then the front of the moving ruler will have t' equal to some negative time, the clock at the back of the moving ruler will read some positive t', and the clock in the middle will read t' = 0 when the fixed ruler's clock reads t=0. My question is, how do we apply time dilation (or lorentz transformations) to this problem in order to find out exactly how far ahead in time the back of the ruler is, and how far in time behind the front of the ruler is.