1. What is the speed of a beam of pions if their average lifetime is measured to be 4.34×10-8s? At rest, their lifetime is 2.60×10-8s. - Would I use velocity= distance/time? 4.34/2.6=velocity 2. A certain star is 70.6 light-years away. How many years would it take a spacecraft traveling 0.910c to reach that star from Earth, as measured by observers on Earth? How many years would it take to reach that star from Earth, as measured by observers on the spacecraft? - For the first part, would it be 70.6/sqrt(1-.910)? -For the second part, would it be the answer from part 1 divided by sqrt(1-.910)?