University Physics Volume 1

# Key Terms

### Key Terms

absolute pressure
sum of gauge pressure and atmospheric pressure
Archimedes’ principle
buoyant force on an object equals the weight of the fluid it displaces
Bernoulli’s equation
equation resulting from applying conservation of energy to an incompressible frictionless fluid: $p+12ρv2+ρgh=constant,p+12ρv2+ρgh=constant,$ throughout the fluid
Bernoulli’s principle
Bernoulli’s equation applied at constant depth:
$p1+12ρv12=p2+12ρv22p1+12ρv12=p2+12ρv22$
buoyant force
net upward force on any object in any fluid due to the pressure difference at different depths
density
mass per unit volume of a substance or object
flow rate
abbreviated Q, it is the volume V that flows past a particular point during a time t, or $Q=dV/dtQ=dV/dt$
fluids
liquids and gases; a fluid is a state of matter that yields to shearing forces
gauge pressure
pressure relative to atmospheric pressure
hydraulic jack
simple machine that uses cylinders of different diameters to distribute force
hydrostatic equilibrium
state at which water is not flowing, or is static
ideal fluid
fluid with negligible viscosity
laminar flow
type of fluid flow in which layers do not mix
Pascal’s principle
change in pressure applied to an enclosed fluid is transmitted undiminished to all portions of the fluid and to the walls of its container
Poiseuille’s law
rate of laminar flow of an incompressible fluid in a tube: $Q=(p2−p1)πr48ηl.Q=(p2−p1)πr48ηl.$
Poiseuille’s law for resistance
resistance to laminar flow of an incompressible fluid in a tube: $R=8ηlπr4R=8ηlπr4$
pressure
force per unit area exerted perpendicular to the area over which the force acts
Reynolds number
dimensionless parameter that can reveal whether a particular flow is laminar or turbulent
specific gravity
ratio of the density of an object to a fluid (usually water)
turbulence
fluid flow in which layers mix together via eddies and swirls
turbulent flow
type of fluid flow in which layers mix together via eddies and swirls
viscosity
measure of the internal friction in a fluid