1. The problem statement, all variables and given/known data a) Event A = [ct(A)=1, x(A)=5, y(A)=0, z(A)=0] precedes event B = [ct(B)=2, x(B)=1, y(B)=0, z(B)=0]. What is the nature of the interval (HAVE DONE THIS). Then, it is desired to transform to another inertial sysyem O', moving at velocity, vi, relative to O, where the temporal order of the two events are reversed ie t'(B)[tex]\leq[/tex]t'(A). What condition on v does this requirement impose? 2. Relevant equations N/A for second part I assume! 3. The attempt at a solution Have worked out that the nature of the interval is "Spacelike". Also I know that to transform to another inertial system, the velocity normally becomes -vi. However, I don't know if the temporal order will mean that something different happens, and it just being negative seems too easy an answer! Any help would be appreciated.