Pressure ?

Pressure is defined as a normal force exerted by a fluid per unit area. We speak of pressure when we deal with a fluid or gas. The counterpart of pressure in a solid is normal stress.


The actual pressure at spesific point is called absolute pressure, it is measured relative to absolute zero pressure. Unfortunately, most pressure measuring device is calibrated to read zero pressure in atmospheric pressure, so they indicate the difference between the absulte pressure and the atmospheric pressure. The difference is called the gage pressure. The pressure below atmospheric pressure is called vacuum pressure.



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