[填空题]
An astronaut on a spaceship traveling at 0.75c nblkzg9: s(yfcp:3 ;irelative to )f sdx3jya 4 5ki*tf2qEarth measures his ship to be 25 m long. On the ship, he eats his lunch in5aifk*2 j4qtfd x3sy) 23 min.
(a) What length is the spaceship according to observers on Earth? L = m
(b) How long does the astronaut's lunch take to eat according to observers on Earth? $\Delta t$ = min
