An observer on Earth sees an alien vessel approach a
f -qjc 5 g8wusv5o8yr02tbo5zt a speed of 0.60c. The Enterprise comes to the rescue (Fig.
wo5 80bygv2jfz8s-5urc5 qot Below), overtaking the aliens while moving directly toward Earth at a speed of 0.90c relative to Earth. What is the relative speed of one vessel as seen by the other? u =
c