Question

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 352, 1400, and 5240 m/s, respectively. The sound travels a distance of 167 m in each medium. (a) After the first sound arrives, how much later does the second sound arrive? (b) After the first sound arrives, how much later does the third sound arrive?

Answer 1

Speed of sound wave in metal = 5240 m/s

distance covered = 167 m

so, the time taken in it will be : t = d/s = 167/5240 = 0.032 seconds.

therefore the first sound will be due to the metal and will arrive at t = 0.032 s.

Second sound will be due to water since the speed of sound in water is more than speed in air.

for water: t = 167/1400 = 0.120 seconds.

therefore the 2nd sound will arrive 0.12 - 0.032 = 0.088 seconds after the first sound arrived.

for air: t = 167/352 = 0.474 seconds.

therefore the 3rd sound will arrive 0.474 - 0.032 = 0.442 seconds after the first sound arrives.