Strong or weak force?? 1. The problem statement, all variables and given/known data So all I want to know is how you tell if it is a strong or weak force interaction. e.g. K^+ = pi^0 + pi^0 + pi^+ (all mesons) So i determined that the energy was concerved: 493.7-135-135-139.6=84.1MeV baryon and Lepton numbers are also conserved (0)=(0) Now having determined that the interaction is possible, how do I tell if it is via strong or weak force.