A research submersible rated for a maximum allowable absolute pressure of 2.40×105Pa operates in two environments.
• Environment A: a mountain lake located 3000m above sea level, where the atmospheric pressure is 7.00×104Pa. The lake water has density 1000kgm−3.
• Environment B: the open ocean at sea level, where the atmospheric pressure is 1.01×105Pa and the seawater density is 1025kgm−3.
Take g=9.80ms−2 in both environments.
(a) Determine the maximum depth to which the submersible can descend in Environment A without exceeding its pressure rating.
(b) Determine the maximum depth for Environment B under the same constraint.
(c) Compare the two depths by calculating hB−hA and explain, using physical reasoning, why the difference has that sign and magnitude.
(d) The lake’s maximum depth is 150m. If the submersible descends to the lake bottom, calculate the absolute pressure it experiences and evaluate whether this depth is within the safety margin implied by its rating.