# Hydrostatics: Fluids at Rest

The Hydrostatics is the science of fluids with no motion. A fluid is defined as a substance that continually flows under an applied shear stress regardless of how small the applied stress. All liquids and all gases are fluids. The term fluid is usually mistaken as liquid, but it actually covers a lot of the phases of matter (liquids, gases, plasmas and others).

## Basic Concepts

Studying the science of Hydrostatics, we are forced to realize a number of basic concepts of physics are as follows. The density (designated by the script Greek "${\displaystyle \rho \,}$", said "rho"), which is equal to the mass divided over the volume of an object. Density is measured in kilograms per cubic meter (${\displaystyle kg/m^{3}}$).

${\displaystyle \rho \,={\frac {m}{V}}}$

Pressure (P), which is the strength over the area and is measured in N/m (Pa.) (${\displaystyle N/m^{2}}$).

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

## Pascal's law

Pascal, in his law, states that at equilibrium state of rest, the pressure acting on every single point in the fluid, excluding the pressure due to gravitational force, will be constant. It states that the pressure applied in an enclosed fluid is proportional to the total pressure in the enclosure.

## Buoyancy

The buoyancy of an object is the relationship between the object's density to the density of the fluid in which it is submerged.