1. The problem statement, all variables and given/known data 5. What is the average distance travelled by a muon with an energy of 5 GeV? 500 GeV? (assume v is approximately c) 2. Relevant equations 3. The attempt at a solution I wasn't really sure where to begin with this. I was under the impression that if in both instances, the velocity is approximately c, they would have the same energy? Where is the extra 495 GeV coming from in this transition? I'm pretty sure the mass hasn't changed? Thanks for any help you can offer!