Cosmic ray muons are produced high in the atmosphere (at 8000 m say) and travel toward the earth at very nearly the speed of light (0.998c, say). a given the lifetime of the muon (2.2 x 10-6s) how far would it go before disintegrating, according to pre-relativistic physics? would the muons make it to ground level? b now answer the same question using relativistic physics. (because of time dilation the muons last longer, so they travel farther.) c pions are also produced in the upper atmosphere. in fact, the sequence is proton (from outer space) hits proton (in atmosphere): p+p+pions. the pions then decay into muons: 1 + u +vu; nt + ut + vy. but, the lifetime of the pion is much shorter (2.6 x 10-8s). assuming the pions have the same speed (0.998c) will they reach ground level?