1. The problem statement, all variables and given/known data A beam of pions ([tex]\pi[/tex]-mesons, with rest energy m[tex]\pi[/tex] c2=140 MeV) consisting of 1010 pions/cm^2s moves with speed such that the total energy of each pion is 10^5 MeV. What is the pressure the beam exerts on a surface that absorbs it and brings it to rest? Please note: For some reason my pi's are showing up strangly. The first one is supposed to say pi-mesons and the second one is supposed to be a subscript. Thanks. 2. Relevant equations 3. The attempt at a solution I am not sure where to start. Any help would be appreciated.