Fluid Statics:

If one of your friends claims that she/he can lift an elephant, you will think she/he is joking. Actually, your friend is not joking: a person can indeed lift an elephant by his/her own body weight by standing on the platform of a hydraulic lift. A hydraulic lift is a machine which is based on the mechanical properties of a fluid in hydrostatic equilibrium. The study of the properties of a fluid in hydrostatic equilibrium is called fluid statics.

You may ask : What is hydrostatic equilibrium? This means that in a given volume of a fluid at rest, the individual fluid molecules may move continuously but the mass of the fluid as a whole has zero velocity and zero acceleration. In this section, we wish to study the behaviour of such fluids by asking ourselves : What happens when force/pressure is applied on a fluid at rest? Or, does fluids at rest exert pressure on a body immersed in it? Answers to these questions were discovered by Pascal and Archimedes. Before we discuss the Pascal's law and the Archimedes principle, it is essential to recapitulate the concept of pressure.