1. The problem statement, all variables and given/known data I have correctly figured out part a but am stuck on part b. Thanks for your help in advance. An unstable particle called the pion has a mean lifetime of 25 ns in its own rest frame. A beam of pions travels through the laboratory at a speed of 0.587c. (a) What is the mean lifetime of the pions as measured in the laboratory frame? 30.75 ns (b) How far does a pion travel (as measured by laboratory observers) during this time? m 2. Relevant equations [ Delta t x c (speed of light) ] / 2 3. The attempt at a solution using the answer from part a and converting to meters: [(3.075E-8)(3E8)] / 2 = 4.6125 I've checked for errors and always come up with this number--which according to the web program is incorrect. What am I not doing/understanding?