# Pressure

## Explanation

Pressure is defined as the perpendicular force per unit area of distribution and is measured in N/m2. The SI unit of pressure is pascal (1 Pa = 1 N/m2). As pressure acts normal to the surface over a certain area, it is a type of stress. Pressure can also be interpreted as potential energy per unit volume in some cases. The following is the mathematical expression for pressure.

${\displaystyle p={\frac {F}{A}}}$

Where ${\displaystyle p}$ is the pressure, ${\displaystyle F}$ is the force acting on the surface, and ${\displaystyle A}$ is the area of the surface the force is acting upon.

Apart from solids, fluid can exert pressure too. For example, all the air molecules in our atmosphere exert pressure on the surface of the earth at about 1.01325 × 105 Pa. This is known as the standard atmospheric pressure of the earth. In the same way, if you go swimming deep inside a swimming pool, the water body above you will exert pressure on your body from above in addition to the atmospheric pressure. Adding the two pressures will give you the absolute pressure on your body. If you subtract the atmospheric pressure from your absolute pressure, you get the gauge pressure.