A research 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?