Physics
posted by zahra .
Suppose you have a perfectly spherical water tank with an inside diameter of 8.6 metres. If the drain at the bottom of the tank can't handle a hydrostatic pressure of more than 50 kilopascals, what is the maximum volume of water, in litres, that can be contained in the tank? Assume that gravitational acceleration is exactly 9.81 m/s2.

Height of water makes the pressure. So solve for height.
50kpa/101.3=H/.76m
Now, solve for H. That would be the height of mercury in the tank, but the tank holds water, so multiply H by 13.2. Now you have the depth of the water, use geometry (or calculus) to find the volume.
The author probably had a different technique in mind..