310105c Pressure 2019 (TF)

Pressure

A measure of force applied over a given area, typically expressed in Pascals (Pa).

Pascal (Pa)

The SI unit of pressure, defined as one newton per square meter (1 N/m²).

Kilopascal (kPa)

A unit of pressure equal to 1000 Pascals.

Gauge Pressure

The pressure relative to atmospheric pressure, calculated as the difference between absolute pressure and atmospheric pressure.

Absolute Pressure

The total pressure measured against a perfect vacuum; calculated as local absolute pressure minus vacuum pressure.

Pascal’s Principle

States that external pressure applied to a fluid increases the pressure throughout the fluid.

Fluid Pressure Formula (P)

Calculated as P = F/A, where P is pressure, F is force, and A is area.

Density (ρ)

Mass per unit volume, usually expressed in kg/m³.

Relative Density (ρr)

The density of a fluid compared to the density of water, expressed as ρ/ρw.

Pressure Conversion

1 atm = 101.325 kPa = 14.696 psi.

Fluid Mechanics

The branch of physics that studies fluids (liquids and gases) in motion and at rest.

Vacuum Pressure

The pressure measured below atmospheric pressure; in a perfect vacuum, this pressure is 0 kPa.

Fluid Compressibility

Gases are compressible under pressure, while liquids are generally incompressible.

Hydrostatic Pressure (P)

The pressure exerted by a fluid at rest, calculated using P = P₀ + ρgh.

Head Pressure

The pressure due to the height of a fluid column, influenced by the fluid's density and the gravitational pull.