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Hydrostatic Pressure

Main formula:

Force due to Hydrostatic Pressure =

Hints and tips:

• Check the units used in the problem carefully. Most commonly, metric units are used for all quantities in the problem, and your answer will be in terms of Newtons, i.e. kg m/s² . Less often, English units will be used and your answer will be in terms of pounds, lb. Either way, the units should multiply and divide just as numbers do, which partially checks that you are doing the arithmetic correctly.

• These are usually fairly complicated word problems. Always read the problem carefully and start by drawing a picture of the surface.

• Usually the depth function D(y) is given by y, y + c, y − c, or c − y where c is some constant. Which one it is depends on how you orient your coordinates in the picture.

• The limits a and b correspond to the highest and lowest levels. Again, this depends on how you orient your coordinates in the picture.

• When it’s feasible, check that your answer makes sense. The amount of force due to hydrostatic pressure should always be positive!