Fluids (liquids and gases) flow because they cannot withstand shearing stress. Pressure = Normal Force / Area.
Pressure applied to an enclosed fluid is transmitted undiminished to every portion of the fluid and the walls of the containing vessel. (Applications: Hydraulic lift, hydraulic brakes).
Pressure due to a fluid column: P = hρg (where h is depth, ρ is density, g is gravity).
When a body is partially or fully immersed in a fluid, it experiences an upward buoyant force equal to the weight of the fluid displaced by it.
Equation of Continuity: For steady, incompressible flow, the mass flow rate is constant. A₁v₁ = A₂v₂ (Av = constant).
States that for a streamlined flow of an ideal fluid, the sum of pressure energy, kinetic energy, and potential energy per unit volume is constant. (Applications: Venturi-meter, aerodynamic lift of an airplane).
Viscosity is the internal friction between fluid layers. According to Stokes' Law, the viscous drag force on a spherical body falling through a fluid is F = 6πηrv.
The property of a liquid surface to shrink to the minimum possible surface area. Causes spherical drops.
Capillary Action: The rise or fall of a liquid in a narrow tube. Ascent formula: h = (2T cosθ) / (rρg).