Two relativistic rockets move toward each other. As seen by an observer on earth, rocket A, of proper length 500m, travels with a speed of .8c while rocket B, of proper length 1000m travels with a speed of .6c.
a) What is the speed of the rockets relative to each other?
b) the earthbound observer sets her clock to t=0 when the two noses of the rockets just pass each other. What will the observers cock read when the tails of the rockets just pass each other?