Fluids Flashcards
density units
kg/m^3
density equation
m/v
are fluids described in intensive properties or extensive
intensive
what does changing the amount of a substance do to the density
does not change the density
specific gravity
is the density of that substance compared to the density of water. density of substance/density of water
how is specific gravity compared to water
if it is less than 1 it is less dense than water
if it is equal to 1 then it is equally as heavy as water
if it is greater than one it indicates a substance heavier than water
density of water
1000kg/m^3
1g/cm^3
impulse equation
the force of the collisions multiplied by the duration of collision (Fchange in time)
average magnitude of force created by the collisions
force of the collisions multiplied by the duration of the collisions/ time over which the collisions occur
pressure equation
P=F/A
S.I. unit of pressure
Pascal (Pa)
gauge pressure
is the pressure compared to the atmospheric pressure
Fluids at rest pressure
P=rhogy (y is the depth of the fluid) g is the gravitational constant
any fluid pressure open to the atmosphere can be found by
P=rhogy+Patm
Pressure atmosphere equals
101,000 Pa
Pascal’s principle
states that pressure applied anywhere to an enclosed incompressible fluid will be distributed undiminished throughout the fluid
as you go higher in the atmosphere there is less
air pressure up there and fewer molecules above you which means less weight and lower pressure
pressure measured relative to a vacuum is called
absolute pressure
Pabsolute=
Pgauge+ Patm (requires a closed container)
difference between gases and liquids as fluids
gases are compressible while liquids are incompressible
a standing fluid exerts a forces called what on any object floating submerged or sunk in the fluid
buoyant force
magnitude of the buoyant force experienced by an object whether floating, submerged, or sunk is
directly proportional to the volume of the fluid displaced
Fb=rhofluidVfluidg
archimedes principle
shows that the upward buoyant force is equal in magnitude to the weight of the displaced fluid
a sunk object displaces a volume of fluid equal
to its own volume
floating object displaces Vfluid
with mass equal to its own mass
Submerged object displaces Vfluid
with mass equal to its own mass and equal to its own volume
Sunk objects displaces Vfluid
equal to its own volume
molecules in fluids have two types of motion
random translational motion(pressure)
uniform tranlational motion
viscosity is the measure
of the fluids willingness to flow
ideal fluids lack turbulence and this is means that they experience
laminar flow (steady flow) means that any fluid flowing through one point has the same velocity
continuity equation
Q=Av
closer streamlines are to one another the
greater the velocity
assuming constant height as velocity increases
pressure decreases
venturi flow is used to
determine the velocity of a fluid flowing within it
venturi effect is
when you decrease the cross-sectional area this leads to an increase in velocity in which there is a decrease in the pressure
in a pipe where does the fluid have the biggest velocity
in the center
pouseuille’s law describes
flow rate of real fluids
water droplets are formed by
intermolecular forces pulling inward minimizing the surface area by creating a more spherical shape
if the cohesive intermolecular forces are stronger in a tube with water
convex surface is formed as the fluid is pulled upward
if the adhesive forces are stronger
concave surface is formed
how does the body prevent alveolar collapse
surfactant
