[填空题]
Calculate the maximum kinetic /2omn s4 7vnm wd1/ztyenergy of the e9j7y p7xwr kp tfrd h4+3+ldoq2u +rv6lectron in the decay $\mu^- \to e^- + \bar{\nu}_e + \nu_\mu$. [Hint: In what direction do the two neutrinos move relative to the electron in order to give the latter the maximum kinetic energy? Both energy and momentum are conserved; use relativistic formulas.] $\text{KE}_{\text{e}^-}$ MeV
