1. The problem statement, all variables and given/known data After being produced in a collision between elementary particles, a positive pion must travel down a 1.00 km long tube to reach an experimental area. A positive pion has an average lifetime of to = 2.60*10^(-8)s; the pion we are considering has this lifetime. How fast must the pion travel if it is not to decay before it reaches the end of the tube? (Since u will be very close to c, write u=(1−Δ)c and give your answer in terms of Δ rather than u.) 2. Relevant equations Δt = Δto/(1 - u^2/c^2)^(1/2) 3. The attempt at a solution I don't really know where I'm going with this?