Dolphins emit clicks of sound for communication and echolocation. a marine biologist is monitoring a dolphin swimming in seawater where the speed of sound is 1517 m/s. when the dolphin is swimming directly away at 6.8 m/s, the marine biologist measures the number of clicks occuring per second to be at a frequency of 2810 hz. what is the difference (in hz) between this frequency and the number of clicks per second actually emitted by the dolphin?