PHY 1122 Key Words and Definitions

Fluid

A fluid is any substance that can flow and change the shape of the volume that it occupies (gases and liquids can do this)

Density

The density of a material (fluid or solid) is defined as its mass per volume (volumetric mass density). Symbol is “ρ (rho), and the units are typically kg/m³.

Pascals Law

Pressure applied to an enclosed fluid is transmitted undiminished to every portion of the fluid and the walls of the containing vessel.

Archimedes’s Principle

When a body is completely or partially immersed in a fluid, the fluid exerts an upward force on the body equal to the weight of the fluid displaced by the body.

Buoyant Force

The upward push exerted by a fluid (liquid or gas on an object immersed in it, counteracting gravity and caused by the pressure difference between the object's top and bottom.

Flow Line

The path of an individual particle in a moving fluid.

Steady Flow

Overall flow pattern doesn’t change so every element that passes through a given point follows the same flow line

Laminar Flow

Describes a smooth flow

Turbulent flow

Describes a chaotic or erratic pattern of flow

Volume Flow Rate (Continuity Equation)

The measurement of how much fluid is flowing past a selected point over a length of time.

Bernouilli’s Principle

The relation of density, pressure, flow speed, and height of flow.

Pressure

The force exerted perpendicular to the surface of an object per unit area over which that force is distributed