what are a matter that continuously changes shape when subjected to shear force (tangential force?
Fluids
What are not fluids as they resist shape changes, when their shape is changed they maintain that changed shape
Solid
With FLUIDS the stress is proportional to the what?? in r/t to hydrostactics
Rate of change
with SOLIDS stress is proportional to the what? in r/t hydrostatics?
change in shape
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Are liquids and gasses both fluids?
Yes
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what is the big difference between fluids (liq/gas) and solids?
Solids don't change
what is perpendicular forces (normal forces)?
force applied perpendicular to surface
fluids are matter that respond in one of two ways to normal forces (perpendicular forces).
how do liquids respond?
how do gasses respons?
liquids- resistance to compression , minimal volume changes.
Gasses- compressible and easily expandable
equation for force?
F=ma
force= mass X acceleration
what are the 3 forces associated with fluids
-
gravity
-
pressure
-
friction
pressure forces are the result of differences in pressure from one point to another. this is also called the what?
Pressure Gradient
friction is proportional to what?
viscosity
what is the physical property of a fluid that relates shear stress to rate of strain?
viscosity
what is the measure of resistance to flow?
viscosity
what is the quanity of a fluid passing a point per unit of time?
flow
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equation for flow.
give example of how flow is written
F=Q/t
F= mean flow
Q= Quanity
t= time
eg- L/min
mL/hr
etc
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what type of flow is smooth flow free of eddies or turbulance, streamlined
Laminar flow
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with laminar flow, the flow _______________ is the greatest being about twice the mean flow.
in the center
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with laminar flow the flow along the walls of the tube is near what?
zero
just to listen for a basic understanding about flow
your on a boat on the sSt. johns river and just cruising along,(lamina the tide is moving and your just cruisin along, thn you get to down town, and the river narrows (by main street bridge) the watr is jst churning little whirl pools and etc. that is now turbulent
this a picture of laminar flow notice that the flow in the center is the greatest
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laminar (streamlined) flow is described mathmatically by who's law?
Pouiseuille's law
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what is the formula for Pouiseuille's law
π=pie 3.14
r= radius
xP= pressure gradient
n= viscosity
l= length
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With Pouiseuille's law, what 2 thigs are directly proportional
radius4
pressure gradient
with Pouiseuille's law F is directly proportional to the fourth power of the radius. what does this mean in laymen terms
flow through a larger bore needle is faster than a small one
With Pouiseuille's law F is directly proportional to the hydrostatic pressure gradient, what does this mean in laymen terms?
raising the IV pole increases hydrostatic pressure in fluid delivered to a pt by gravity, flow iincreases proportionally
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with Pouiseuille's law what 2 things are inverly proportional to flow
fluid viscosity
length
With Pouiseuille's law give an example of how viscosity is inversly proportional to flow
polycythemic pts have higher blood viscosity, flow reduced
Anemic pt's have low viscosity, so flow increased
With Pouiseuille's law give an example in laymen terms how length is inversly proportional to flow
reducing the length of a needle inclreases flow from an IV bag
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With Pouiseuille's law which factor is the most sensitive to change that will effect flow the most!!!!!
and why?
this will be a test question
Radius
double the radius= increase in flow x 16
Half the radius= decrease flow t0 1/16th
ex 24=16
14= 1
