There is no official or widely verified "solucionario" (solutions manual) for the textbook Curso de Física Moderna
Each chapter in the solucionario typically includes: solucionario+de+curso+de+fisica+moderna+virgilio+acosta320
Better: In muon frame, ground approaches at (0.98c), initial distance to ground is (L_0/\gamma = 1990 m). Time for ground to reach muon = (1990 / (0.98c) \approx 6.77 \mu s). Muon lifetime = (2.2 \mu s). Since 6.77 > 2.2, muon decays before ground arrives — so it does NOT reach. But in Earth frame we found travel time 34 μs, lifetime 11 μs — also not reach. I made an error: 11 μs < 34 μs means NOT reach. So consistent: muon does not reach ground. There is no official or widely verified "solucionario"