During a test dive in 1939, prior to being accepted by the U.S. Navy, the submarine Squalus sank at a point where the depth of water was 70.0m . The temperature at the surface was 24.0 c and at the bottom it was 7.0 c . The density of seawater is 1020kg/m^3 .

Part A:

A diving bell was used to rescue 33 trapped crewmen from the Squalus. The diving bell was in the form of a circular cylinder 2.30m high, open at the bottom and closed at the top. When the diving bell was lowered to the bottom of the sea, to what height did water rise within the diving bell? (Hint: You may ignore the relatively small variation in water pressure between the bottom of the bell and the surface of the water within the bell.)

Part B:

At what gauge pressure must compressed air have been supplied to the bell while on the bottom to expel all the water from it?