# Net downward force

You are assigned the design of a cylindrical, pressurized water tank for a future colony on Mars, where the acceleration due to gravity is 3.71 \;{\rm m}/{\rm s}^{2}. The pressure at the surface of the water will be 150 kPa and the depth of the water will be 13.5 m. The pressure of the air in the building outside the tank will be 88.0 kPa.

Find the net downward force on the tank's flat bottom, of area 2.25 m^2, exerted by the water and air inside the tank and the air outside the tank.?

im clueless

## Answers and Replies

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What's the static fluid pressure at a given depth beneath the surface of a fluid? When calculating the total pressure above the tank's bottom, don't forget to add the pressure at the surface.

To find the net pressure on the tank bottom, don't forget to consider the pressure of the outside air pushing from below.

Once you have the net pressure, you can figure out the net force, given the area.