An explosion occurs at the end of a pier. The sound reaches the other end of the pier by traveling through three media: air, fresh water, and a slender metal handrail. The speeds of sound in air, water, and the handrail are 343, 1482, and 5040 m/s, respectively. The sound travels a distance of 125 m in each medium.
(a) Through which medium does the sound arrive first, second, and third?
(b) After the first sound arrives, how much later do the second and third sounds arrive?