The force acting normally on (at right angles to) a unit area of surface, or the ratio of force to area. The SI unit of pressure is the pascal (Pa = newton/meter2) but several other pressure units, including the atmosphere (101.325 kPa), the bar (100 kPa), and the millimeter of mercury (mmHg = 133.322 Pa), are in common use.
If a weight of 20 newtons (N) acts at right angles to on an area of 2 m2, the pressure it exerts is calculated as follows:
According to the kinetic theory of gases, the pressure in a closed container of gas arises from the bombardment of the container walls by the molecules: it is proportional to the temperature and inversely proportional to the volume of the gas.
Related category• CLASSICAL MECHANICS
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