1. The problem statement, all variables and given/known data Events A and B are simultaneous in frame F and are 18 km apart on a line that defines the x-axis. A series of spaceships all pass at the same speed in the + x-direction, and they have synchronized their clocks so that together they make up a moving frame F'. They time events A and B to be separated by 0.80 microseconds. What is the speed of the spaceships? How far apart in space do they measure the two events to be? 2. Relevant equations γ = 1/sqrt(1 - (u/c)^2) (1) Δx' = γ(Δx - uΔt) (2) Δt' = γ(Δt - uΔx)/(c^2) 3. The attempt at a solution a. To get the speed, I used Δt = 0, Δt' = 8*10^-7 s, and Δx = 18000m. I plugged these into equation 2 and did a little bit of algebra to get: Δt' = 4*10^6 m/s = c/75 b. To get the distance, I used Δx = 18000m, Δt = 0, and u = c/75, which I plugged into equation 1. When I did this, I got: Δx' = 18001.6m My answer to part a seems plausible, but my answer to part b just looks wrong to me. It seems like Δx' should not be so close to Δx. Are my solutions correct? If not, where did I mess up? Thanks!