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active transport : the process in which a living membrane expends energy to move substances across
https://openstax.org/books/college-physics-2e/pages/12-glossary
Bernoulli’s equation : the equation resulting from applying conservation of energy to an incompressible frictionless fluid:P+ 1/2pv2+pgh= constant , through the fluid
https://openstax.org/books/college-physics-2e/pages/12-glossary
Bernoulli’s principle : Bernoulli’s equation applied at constant depth:P1+ 1/2pv12=P2+ 1/2pv22
https://openstax.org/books/college-physics-2e/pages/12-glossary
dialysis : the transport of any molecule other than water through a semipermeable membrane from a region of high concentration to one of low concentration
https://openstax.org/books/college-physics-2e/pages/12-glossary
diffusion : the movement of substances due to random thermal molecular motion
https://openstax.org/books/college-physics-2e/pages/12-glossary
flow rate : abbreviatedQ, it is the volumeVthat flows past a particular point during a timet, orQ = V/t
https://openstax.org/books/college-physics-2e/pages/12-glossary
fluid dynamics : the physics of fluids in motion
https://openstax.org/books/college-physics-2e/pages/12-glossary
laminar : a type of fluid flow in which layers do not mix
https://openstax.org/books/college-physics-2e/pages/12-glossary
liter : a unit of volume, equal to 10−3m3
https://openstax.org/books/college-physics-2e/pages/12-glossary
osmosis : the transport of water through a semipermeable membrane from a region of high concentration to one of low concentration
https://openstax.org/books/college-physics-2e/pages/12-glossary
osmotic pressure : the back pressure which stops the osmotic process if one solution is pure water
https://openstax.org/books/college-physics-2e/pages/12-glossary
Poiseuille’s law : the rate of laminar flow of an incompressible fluid in a tube:Q= (P2−P1)πr4/8ηl
https://openstax.org/books/college-physics-2e/pages/12-glossary
Poiseuille’s law for resistance : the resistance to laminar flow of an incompressible fluid in a tube:R= 8ηl/πr4
https://openstax.org/books/college-physics-2e/pages/12-glossary
relative osmotic pressure : the back pressure which stops the osmotic process if neither solution is pure water
https://openstax.org/books/college-physics-2e/pages/12-glossary
reverse dialysis : the process that occurs when back pressure is sufficient to reverse the normal direction of dialysis through membranes
https://openstax.org/books/college-physics-2e/pages/12-glossary
reverse osmosis : the process that occurs when back pressure is sufficient to reverse the normal direction of osmosis through membranes
https://openstax.org/books/college-physics-2e/pages/12-glossary
Reynolds number : a dimensionless parameter that can reveal whether a particular flow is laminar or turbulent
https://openstax.org/books/college-physics-2e/pages/12-glossary
semipermeable : a type of membrane that allows only certain small molecules to pass through
https://openstax.org/books/college-physics-2e/pages/12-glossary
terminal speed : the speed at which the viscous drag of an object falling in a viscous fluid is equal to the other forces acting on the object (such as gravity), so that the acceleration of the object is zero
https://openstax.org/books/college-physics-2e/pages/12-glossary
turbulence : fluid flow in which layers mix together via eddies and swirls
https://openstax.org/books/college-physics-2e/pages/12-glossary
viscosity : the friction in a fluid, defined in terms of the friction between layers
https://openstax.org/books/college-physics-2e/pages/12-glossary
viscous drag : a resistance force exerted on a moving object, with a nontrivial dependence on velocity
https://openstax.org/books/college-physics-2e/pages/12-glossary
Flow rateQQis defined to be the volumeVVflowing past a point in timett, orQ=VtQ=VtwhereVVis volume andttis time.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
The SI unit of volume ism3m3.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Another common unit is the liter (L), which is10−3m310−3m3.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Flow rate and velocity are related byQ=Av¯Q=Av¯whereAAis the cross-sectional area of the flow andv¯v¯is its average velocity.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
For incompressible fluids, flow rate at various points is constant. That is,Q1=Q2A1v¯1=A2v¯2n1A1v¯1=n2A2v¯2.Q1=Q2A1v¯1=A2v¯2n1A1v¯1=n2A2v¯2.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Bernoulli’s equation states that the sum on each side of the following equation is constant, or the same at any two points in an incompressible frictionless fluid:P1+12ρv12+ρgh1=P2+12ρv22+ρgh2.P1+12ρv12+ρgh1=P2+12ρv22+ρgh2.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Bernoulli’s principle is Bernoulli’s equation applied to situations in which depth is constant. The terms involving depth (or heighth) subtract out, yieldingP1+12ρv12=P2+12ρv22.P1+12ρv12=P2+12ρv22.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Bernoulli’s principle has many applications, including entrainment, wings and sails, and velocity measurement.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Power in fluid flow is given by the equationP1+12ρv2+ρghQ=power,P1+12ρv2+ρghQ=power,where the first term is power associated with pressure, the second is power associated with velocity, and the third is power associated with height.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Laminar flow is characterized by smooth flow of the fluid in layers that do not mix.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Turbulence is characterized by eddies and swirls that mix layers of fluid together.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Fluid viscosityηηis due to friction within a fluid. Representative values are given inTable 12.1. Viscosity has units of(N/m2)s(N/m2)sorPaâ‹sPaâ‹s.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Flow is proportional to pressure difference and inversely proportional to resistance:Q=P2−P1R.Q=P2−P1R.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
For laminar flow in a tube, Poiseuille’s law for resistance states thatR=8ηlπr4.R=8ηlπr4.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Poiseuille’s law for flow in a tube isQ=(P2−P1)πr48ηl.Q=(P2−P1)πr48ηl.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
The pressure drop caused by flow and resistance is given byP2−P1=RQ.P2−P1=RQ.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
The Reynolds numberNRNRcan reveal whether flow is laminar or turbulent. It isNR=2ρvrη.NR=2ρvrη.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
ForNRNRbelow about 2000, flow is laminar. ForNRNRabove about 3000, flow is turbulent. For values ofNRNRbetween 2000 and 3000, it may be either or both.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
When an object moves in a fluid, there is a different form of the Reynolds numberNR′=ρvLη(object in fluid),NR′=ρvLη(object in fluid),which indicates whether flow is laminar or turbulent.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
ForNR′NR′less than about one, flow is laminar.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
ForNR′NR′greater than106106, flow is entirely turbulent.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Diffusion is the movement of substances due to random thermal molecular motion.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
The average distancexrmsxrmsa molecule travels by diffusion in a given amount of time is given byxrms=2Dt,xrms=2Dt,whereDDis the diffusion constant, representative values of which are found inTable 12.2.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
whereDDis the diffusion constant, representative values of which are found inTable 12.2.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Osmosis is a process by which molecules of a solvent pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus, equalizing the solute concentrations on each side of the membrane.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Dialysis is the transport of any other molecule through a semipermeable membrane due to its concentration difference.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Both processes can be reversed by back pressure.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
Active transport is a process in which a living membrane expends energy to move substances across it.
https://openstax.org/books/college-physics-2e/pages/12-section-summary
absolute zero : the lowest possible temperature; the temperature at which all molecular motion ceases
https://openstax.org/books/college-physics-2e/pages/13-glossary
Avogadro’s number : NANA, the number of molecules or atoms in one mole of a substance;NA=6.02×1023NA=6.02×1023particles/mole
https://openstax.org/books/college-physics-2e/pages/13-glossary
Boltzmann constant : kk, a physical constant that relates energy to temperature;k=1.38×10–23J/Kk=1.38×10–23J/K
https://openstax.org/books/college-physics-2e/pages/13-glossary
Celsius scale : temperature scale in which the freezing point of water is0ºC0ºCand the boiling point of water is100ºC100ºC
https://openstax.org/books/college-physics-2e/pages/13-glossary
coefficient of linear expansion : αα, the change in length, per unit length, per1ºC1ºCchange in temperature; a constant used in the calculation of linear expansion; the coefficient of linear expansion depends on the material and to some degree on the temperature of the material
https://openstax.org/books/college-physics-2e/pages/13-glossary
coefficient of volume expansion : ββ, the change in volume, per unit volume, per1ºC1ºCchange in temperature
https://openstax.org/books/college-physics-2e/pages/13-glossary
critical point : the temperature above which a liquid cannot exist
https://openstax.org/books/college-physics-2e/pages/13-glossary
critical pressure : the minimum pressure needed for a liquid to exist at the critical temperature
https://openstax.org/books/college-physics-2e/pages/13-glossary
critical temperature : the temperature above which a liquid cannot exist
https://openstax.org/books/college-physics-2e/pages/13-glossary
Dalton’s law of partial pressures : the physical law that states that the total pressure of a gas is the sum of partial pressures of the component gases
https://openstax.org/books/college-physics-2e/pages/13-glossary
degree Celsius : unit on the Celsius temperature scale
https://openstax.org/books/college-physics-2e/pages/13-glossary
degree Fahrenheit : unit on the Fahrenheit temperature scale
https://openstax.org/books/college-physics-2e/pages/13-glossary
dew point : the temperature at which relative humidity is 100%; the temperature at which water starts to condense out of the air
https://openstax.org/books/college-physics-2e/pages/13-glossary
Fahrenheit scale : temperature scale in which the freezing point of water is32ºF32ºFand the boiling point of water is212ºF212ºF
https://openstax.org/books/college-physics-2e/pages/13-glossary
ideal gas law : the physical law that relates the pressure and volume of a gas to the number of gas molecules or number of moles of gas and the temperature of the gas
https://openstax.org/books/college-physics-2e/pages/13-glossary
Kelvin scale : temperature scale in which 0 K is the lowest possible temperature, representing absolute zero
https://openstax.org/books/college-physics-2e/pages/13-glossary
mole : the quantity of a substance whose mass (in grams) is equal to its molecular mass
https://openstax.org/books/college-physics-2e/pages/13-glossary
partial pressure : the pressure a gas would create if it occupied the total volume of space available
https://openstax.org/books/college-physics-2e/pages/13-glossary
percent relative humidity : the ratio of vapor density to saturation vapor density
https://openstax.org/books/college-physics-2e/pages/13-glossary
phase diagram : a graph of pressure vs. temperature of a particular substance, showing at which pressures and temperatures the three phases of the substance occur
https://openstax.org/books/college-physics-2e/pages/13-glossary
PVdiagram : a graph of pressure vs. volume
https://openstax.org/books/college-physics-2e/pages/13-glossary
relative humidity : the amount of water in the air relative to the maximum amount the air can hold
https://openstax.org/books/college-physics-2e/pages/13-glossary
saturation : the condition of 100% relative humidity
https://openstax.org/books/college-physics-2e/pages/13-glossary
sublimation : the phase change from solid to gas
https://openstax.org/books/college-physics-2e/pages/13-glossary
temperature : the quantity measured by a thermometer
https://openstax.org/books/college-physics-2e/pages/13-glossary
thermal energy : KE¯KE¯, the average translational kinetic energy of a molecule
https://openstax.org/books/college-physics-2e/pages/13-glossary
thermal equilibrium : the condition in which heat no longer flows between two objects that are in contact; the two objects have the same temperature
https://openstax.org/books/college-physics-2e/pages/13-glossary
thermal expansion : the change in size or volume of an object with change in temperature
https://openstax.org/books/college-physics-2e/pages/13-glossary
thermal stress : stress caused by thermal expansion or contraction
https://openstax.org/books/college-physics-2e/pages/13-glossary
triple point : the pressure and temperature at which a substance exists in equilibrium as a solid, liquid, and gas
https://openstax.org/books/college-physics-2e/pages/13-glossary
vapor : a gas at a temperature below the boiling temperature
https://openstax.org/books/college-physics-2e/pages/13-glossary
vapor pressure : the pressure at which a gas coexists with its solid or liquid phase
https://openstax.org/books/college-physics-2e/pages/13-glossary
zeroth law of thermodynamics : law that states that if two objects are in thermal equilibrium, and a third object is in thermal equilibrium with one of those objects, it is also in thermal equilibrium with the other object
https://openstax.org/books/college-physics-2e/pages/13-glossary
Temperature is the quantity measured by a thermometer.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Temperature is related to the average kinetic energy of atoms and molecules in a system.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Absolute zero is the temperature at which there is no molecular motion.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
There are three main temperature scales: Celsius, Fahrenheit, and Kelvin.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Temperatures on one scale can be converted to temperatures on another scale using the following equations:TºF=95TºC+32TºF=95TºC+32TºC=59TºF−32TºC=59TºF−32TK=TºC+273.15TK=TºC+273.15TºC=TK−273.15TºC=TK−273.15
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Systems are in thermal equilibrium when they have the same temperature.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Thermal equilibrium occurs when two bodies are in contact with each other and can freely exchange energy.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
The zeroth law of thermodynamics states that when two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Thermal expansion is the increase, or decrease, of the size (length, area, or volume) of a body due to a change in temperature.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Thermal expansion is large for gases, and relatively small, but not negligible, for liquids and solids.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
Linear thermal expansion isΔL=αLΔT,ΔL=αLΔT,whereΔLΔLis the change in lengthLL,ΔTΔTis the change in temperature, andααis the coefficient of linear expansion, which varies slightly with temperature.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
The change in area due to thermal expansion isΔA=2αAΔT,ΔA=2αAΔT,whereΔAΔAis the change in area.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
The change in volume due to thermal expansion isΔV=βVΔT,ΔV=βVΔT,whereββis the coefficient of volume expansion andβ≈3αβ≈3α. Thermal stress is created when thermal expansion is constrained.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
The ideal gas law relates the pressure and volume of a gas to the number of gas molecules and the temperature of the gas.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
The ideal gas law can be written in terms of the number of molecules of gas:PV=NkT,PV=NkT,wherePPis pressure,VVis volume,TTis temperature,NNis number of molecules, andkkis the Boltzmann constantk=1.38×10–23J/K.k=1.38×10–23J/K.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
A mole is the number of atoms in a 12-g sample of carbon-12.
https://openstax.org/books/college-physics-2e/pages/13-section-summary
The number of molecules in a mole is called Avogadro’s numberNANA,NA=6.02×1023mol−1.NA=6.02×1023mol−1.
https://openstax.org/books/college-physics-2e/pages/13-section-summary