A hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake. She hears the echo 3.7 ss after shouting. The speed of sound in air is 343 m/sm/s. Determine the length of the lake. A sailor strikes the side of his ship just below the waterline. He hears the echo of the sound reflected from the ocean floor directly below 3.2 ss later. How deep is the ocean at this point?