Dolphins and sound?

Question

Will humans be able to hear a sound that has a wavelenth of 26.314 m (57 Hz, 1500 m/s)? Explain?

If a dolphin sends out an ultrasound underwater toward a boat and the sound returns in 1 second, how far away is the boat?

Answer 1

Most people can hear sounds with frequencies as low as 16 Hz.  On a diatonic scale with middle C = 256 Hz, 57 Hz is a B-flat 2 octaves below middle C, a note you can play on any piano, possibly reachable by a true basso-profundo. On a scale with A = 440 Hz, 57 Hz is a "flat" B-flat (not quite up to pitch).

If a dolphin sends out an ultrasound underwater toward a boat and the sound returns in 1 second, how far away is the boat?

The sound takes 0.5 s to reach the boat, and 0.5 s to return, so the boat is

(1,500 m/s)(0.5 s) = 750 m away.