Pressure is defined as force per
unit area. It is usually more convenient to use pressure rather than force to
describe the influences upon fluid behavior. The standard unit for pressure is
the Pascal, which is a Newton per square meter.
For an object sitting on a
surface, the force pressing on the surface is the weight of the object, but in
different orientations it might have a different area in contact with the
surface and therefore exert a different pressure.
