1. The problem statement, all variables and given/known data Suppose a rod measured in the S frame has a gradient of M. The S' frame travels at v (along x-axis) relative to S. What is the gradient of the rod in the S' frame? 2. Relevant equations Lorentz tranformations 3. The attempt at a solution y'=y x' = [itex]\gamma[/itex](x-vt) so that m = y'/[itex]\gamma[/itex](x-vt) This seems straightforward enough, which is why I'm worried. I'm not used to problems in relativity being this easy. Have I missed anything?