Aresearch vessel is mapping the bottom of the ocean using sonar. it emits a short sound pulse called "ping" downward. the frequency of the sound is 5600 hz. in water sound propagates at a speed of 1474 m/s. the sound pulse is then reflected back from the bottom of the ocean and it is detected by the vessel 8.88 s after it was emitted. how deep is the ocean just below the vessel?