A scientific vessel in the polar region sends a sound pulse downward into the sea. An echo from the flat underside of an iceberg returns to the ship after 0.40s. A later echo from the sea-bed below the iceberg returns 2.4s after the pulse was emitted. Take the speed of sound in the sea water at that time to be 1450m/s.
(i) Calculate the depth of the bottom surface of the iceberg below the ship.
(ii) Calculate the depth of the sea-bed below the ship.
(iii) Hence find the thickness of the water layer between the bottom of the iceberg and the sea-bed.
(iv) Later, a fall in water temperature reduces the speed of sound to 1400m/s. If the distances remain the same, determine the revised time that will elapse before the sea-bed echo is received.