Answer
See explanation.
Work Step by Step
a. The rest mass of the pion is 270(0.511 MeV) = 138 MeV.
The rest mass of the muon is 207(0.511 MeV) = 106 MeV.
The energy released in the decay is the difference, 32 MeV.
b. The muon has less mass than the pion, so a muon can’t decay into a pion because there isn’t enough mass-energy to do so.
