[问答题]
A pi meson of rest m*ahagof h/5,( cz5obd o83bnnaq2ib47 bp 4oj ass $m_\pi$ decays at rest into a muon (rest mass $m_\mu$) and a neutrino of negligible or zero rest mass. Show that the kinetic energy of the muon is $KE_\mu = \frac{(m_\pi - m_\mu)^2 c^2}{2m_\pi}$.
