An ocean fishing boat is drifting just above a school of tuna on a foggy day. Without warning, an engine backfire occurs on another boat 1.55 km away (Fig. 12–33). How much time elapses before the backfire is heard

VIDEO TRANSCRIPT

This is Giancoli Answers with Mr. Dychko. The time it takes for the sound to travel from the backfiring engine to the fish or the fisherman is going to be the distance divided by the speed of sound. So, the distance to the fisherman and to the fish is the same because we're told the boat is just above the school of tuna. And so that means that they're really close and the distances to this backfiring ship are the same so, the times it takes to the sound to get to the fish is the distance divided by the speed of sound going through sea water. And so that's 1.55 times 10 to the 3 meters divided by 1560 meters per second, and you get that sea water speed by looking at table 12-1 on page 329, and that's 0.994 seconds. And the time it takes to get to the fishermen is the same distance divided by the speed of sound in air, 343 meters per second. So, it takes significantly longer for the fishermen to hear that sound, and they will hear it after 4.52 seconds.