Possible Duplicate:
Double light speed
Someting almost faster than light traveling on something else almost faster than light
Well I've been wondering quite a long time about this problem. If you had let's say 10 rockets, each of them having a length enough to provide space for an acceleration of another rocket inside. Each rocket would accelerate from 0, to 1/10 of speed of light. From the observers point of view, wouldn't the last rocket achieve the speed of light (since the speeds add up).