Imagine a Rip van Winkle type who lives in the mountains. Just before going to sleep, he yells, “WAKE UP,” and the sound echoes off the nearest mountain and returns 8 hours later. Show that the distance between Rip and the imaginary mountain is nearly 5000 km (about the distance from New York to San Francisco).

Solution 6P We know the that velocity of sound is v = 330 m/s. Distance covered in 8 hours is given by s = v × t s = 330 × 8 × 3600 s = 9504000 m Then the distance of imaginary mountain is s/2 = 9504000/2 = 4752000 m 4752 km ~ 5000 km