Pressure as a physical quantity:
pressure = force per unit area.
SI unit:
pascal 1 pascal(pa) = N/m^2
somtimes measured in bars or tonnes per square inch.
Pressure in a
liquid: p=h
pg where h is the
height of the liquid column (in
metres),
p is the
density of the liquid and g is the acceleration due to
gravity, usually 9.81 metres per
second squared.
Pressure is measured using various types of
manometers. Atmospheric pressure is measured using a
barometer.