Question
A tank with a square base of area $1.0 \mathrm{~m}^2$ is divided by a vertical partition in the middle. The bottom of the partition has a small-hinged door of area $20 \mathrm{~cm}^2$. The tank is filled with water in one compartment, and an acid (of relative density 1.7 ) in the other, both to a height of 4.0 m . compute the force necessary to keep the door close.