Physics 207: Lecture 22, Pg 1Physics 207,Physics 207, Lecture 22, NovLecture 22, Nov 18 18 ‘‘0909TODAY:TODAY:Static FluidsStatic FluidsPascalPascal’’s Principle (Pressure s Principle (Pressure vs vs depth)depth)ArchimedesArchimedes’’ Principle (Buoyancy) Principle (Buoyancy)Dynamic FluidsDynamic Fluids Ideal Fluids Continuity Equation Bernoulli’s Equation, Venturi Effect Streamlines Turbulence ViscosityWavesWavesASSIGNMENTS:ASSIGNMENTS:Read Chapter 20.1 - 20.6 Read Chapter 20.1 - 20.6 Travelling Travelling WavesWavesRead Read Chaper Chaper 21.1 - 21.421.1 - 21.4 SuperpositionSuperpositionHonors LectureHonors Lecture Friday 8:50 AMFriday 8:50 AMProf. Tom Yin, Prof. Tom Yin, ““The Physics of HearingThe Physics of Hearing””Physics 207: Lecture 22, Pg 2BuoyancyBuoyancyWhen an object (or portion of an object) is immersed in afluid, it displaces fluid. The displaced fluid’s volumeequals the volume of the portion of the object that isimmersed in the fluid.Suppose the fluid has density ρf and the object displacesvolume Vf of fluid. Archimedes’ principle in equation formisPhysics 207: Lecture 22, Pg 3Physics 207: Lecture 22, Pg 7Buoyancy and FishBuoyancy and FishFish adjust their ρfish=ρwater and FB=Wfish("neutrally buoyant"). How?Teleost Fish use a Swim Bladder:- flexible, membrane-enclosed bag of gas- fish secretes gas into bag, changing Vfish and ρfish.Physics 207: Lecture 22, Pg 15Static FluidsStatic FluidsPascalPascal’’s Principle (Pressure s Principle (Pressure vs vs depth)depth)ArchimedeArchimede’’s s Principle (Buoyancy)Principle (Buoyancy)Dynamic FluidsDynamic FluidsIdeal FluidsContinuity EquationBernoulli’s Equation, Venturi EffectStreamlinesTurbulenceViscosityWavesWavesPhysics 207: Lecture 22, Pg 16Physics 207: Lecture 22, Pg 17Continuity Equation EXAMPLE: Gasoline through a pipeContinuity Equation EXAMPLE: Gasoline through a pipeEstimate the speed of gasoline flowing through thegas pump nozzle when you fill your car with gas.A. 0.1 m/s B. 1 m/s C. 10 m/s D. 100 m/sPhysics 207: Lecture 22, Pg 19Bernoulli’s EquationYou’ll derive this in HW 10 and in Discussion this week!Energy ConservationPhysics 207: Lecture 22, Pg 20The Venturi Effect: A Special Case of Bernoulli’s EquationPhysics 207: Lecture 22, Pg 21The Venturi Effect: A Special Case of Bernoulli’s Equationv1v2h1h2A. h1 = h2B. h1 > h2C. h1 < h2Physics 207: Lecture 22, Pg 24BernoulliBernoulli’’s Equation EXAMPLEs Equation EXAMPLEA large tank of water has a small holea distance h below the surface. Whatis the speed of the water flowing out?Physics 207: Lecture 22, Pg 25Physics 207: Lecture 22, Pg 29Static FluidsStatic FluidsPascalPascal’’s Principle (Pressure s Principle (Pressure vs vs depth)depth)ArchimedesArchimedes’’ Principle (Buoyancy) Principle (Buoyancy)Dynamic FluidsDynamic FluidsIdeal FluidsContinuity EquationBernoulli’s Equation, Venturi EffectStreamlinesTurbulenceViscosityWavesWavesPhysics 207: Lecture 22, Pg 30Physics 207: Lecture 22, Pg 31Physics 207: Lecture 22, Pg 32The speed v of a wave on a stretched string or wire depends on thewire tension FT and the wire's mass per unit length µ.From dimensional analysis, what must be the relation between v, FT,and µ?A. v FT/µB. v (FT/µ)1/2C. v µ/FTD. v
View Full Document