Help with relativity and time dilation

1. Dec 18, 2005

jaterp

This problem i got for school has been driving me crazy >.<

"As seen by one observer, two firecrackers are set off at the same place but separated by 4 seconds in time. As observerd by a second observer, moving with respect to the first, the two firecrackers detonate at places separated by 3 light-seconds in space. As observed by this second observer, how much time is there between the two detonations?
How fast is this second observer moving with respect to the first?"

So basically for the second observer, he sees the detonation happen at different places coz hes moving right ? but where am i suppose to go from there ? I solved for v with time dilation thinking that second observer sees the time as 3 seconds but when i re-read the question i realised i totally misunderstood it and that it was distance between the detonation. Any sort of help will be really appreciated ^^

2. Dec 18, 2005

Staff: Mentor

Start by writing the Lorentz transformations that relate distance and time measurements made in different frames.