FACULTY OF SCIENCE, WINTER 2008
PHYS 126 LEC B3 : Fluids, Fields and Radiation (Instructor: Marc de Montigny)
Walker, Physics, Chapter 15: Fluids
- Section 15-1: Density
- P. 477, Eq. 15-1, Density: ρ = M/V [SI Units: kg/m3]
- P. 477, Table 15-1Densities of Common Substances
- Section 15-2: Pressure
- P. 477, Eq. 15-2, Pressure: P = F/A [SI Units: 1 Pascal (Pa) = 1 Ng/m2]
- P. 480, Eq. 15-5, Gauge Pressure: Pg = P - Patm.
- P. 479, Eq. 15-3, Patm = 101 kPa. In British units, Patm = 14.7 lb/in2.
- P. 508, Problem 8
- Section 15-3: Static Equilibrium in Fluids, Pressure and Depth
- P. 481, Eq. 15-7, Dependence of Pressure on Depth: P2 = P1 - ρgh
- P. 481, Figure 15-2 Pressure Variation with Depth
- P. 483, Figure 15-4 Simple Barometer
- P. 508, Problem 24
- Questions related to the Titanic's wreck
- P. 485, Pascal's Principle: An external pressure applied to an enclosed fluid is transmitted unchanged to every point within the fluid.
- P. 485, Figure 15-7 Hydraulic Lift
- P. 508, Problem 16
- P. 508, Problem 23
- Section 15-4: Archimedes' Principle and Buoyancy
- P. 487, Archimedes' Principle: An object immersed in a fluid experiences an upward buoyant force equal in magnitude to the weight of fluid displaced by the object.
- P. 486, Figure 15-8 Buoyant force due to a fluid
- P. 487, Eq. 15-9, Buoyant Force: Fb = ρfluid g Vdisplaced
- P. 487, Figure 15-9 Buoyant force = weight of displaced fluid. See also this web site
- P. 510, Problem 34
- P. 512, Problem 78
- Section 15-5: Application of Archimedes' Principle
- P. 492, Eq. 15-10, The submerged volume Vsub for a solid of volume Vs and density ρs floating in a fluid of density ρf is given by Vsub = Vs (ρs/ρf)
- P. 510, Problem 38 (Assignment problem; not discussed in class)
- P. 513, Problem 86
- P. 513, Problem 91
- P. 513, Problem 88
- Section 15-6: Fluid Flow and Continuity
- P. 494, Eq. 15-11, Equation of Continuity (General): ρ1 A1 v1 = ρ2 A2 v2
- P. 493, Figure 15-14 Fluid through a pipe of varying diameter
- P. 494, Eq. 15-12, Equation of Continuity (Incompressible Fluids, i.e. uniform densities): A1 v1 = A2 v2
- Section 15-7: Bernouilli's Equation
- P. 495, Figure 15-15 Work done on an element of fluid
- P. 497, Eq. 15-16, Bernouilli's Equation: P1 + ½ρv12 + ρgy1 = P2 + ½ρv22 + ρgy2
- Proof in P. 495 - 495. However, here is a more accurate explanation for the appearance of P. This figure shows the forces (due to different fluid pressures) that are acting of both sides of a fluid element. The magnitude of the net force pushing the fluid element up the pipe is ΔF = (ΔP) A. While this fluid element flows through its own length s, the work done by the surrounding fluid is ΔW = (ΔP) As = (ΔP) V. Then the total work done by the surrounding fluid on this fluid element is W = ∑ΔW = V ∑ΔP = (P1 - P2) V.
- P. 496, Figure 15-16 Fluid pressure in a pipe of varying elevation
- P. 510, Problem 51
- P. 512, Problem 81
- P. 513, Problem 94
- Section 15-8: Applications of Bernouilli's Equation
- P. 498, Figure 15-17 Bernouilli effect on a sheet of paper
- P. 498, Figure 15-18 Airflow and lift in an airplane lift
- P. 499, Figure 15-21 Atomizer
- P. 500, Figure 15-22 Torricelli's Law
- P. 500, Figure 15-23 Maximum height of a stream of water
- Section 15-9: Viscosity [Surface Tension not included]
- P. 501, Eq. 15-18, Coefficient of viscosity (η): P1 - P2 = 8πηvL/A. [Units: 1 poise = 0.1 N•s/m2]
- P. 501, Figure 15-24 Viscosity
- P. 502, Table 15-3 contains viscosities of various fluids
- P. 503, Eq. 15-19, Poiseuille's Equation: ΔV/Δt = (P1 - P2)πr4/8ηL
- P. 502, Example 15-10
- P. 511, Problem 61
- Surface Tension (below) not covered in exams.
- P. 503, Surface Tension: A fluid tends to pull inward on its surface, resulting in a surface of minimum area. The surface of the fluid behaves much like an elastic membrane enclosing the fluid.
- P. 503, Figure 15-25 Surface tension