1. The problem statement, all variables and given/known data Known/Given Water flows through a Venturi meter (mercury [density=13.6E3 kg/m^3] in the manometer). Pipe size: 10.0cm diameter Constriction size: 5.6cm diameter Height difference of mercury: 2.3cm Unknown - Flow Rate (L/s) 2. Relevant equations Bernoulli's - P1 + (1/2)*d*V1^2 = P2 + (1/2)*d*(V2)^2 Flow Rate - I = A1*V1 = A2 * V2 Pressure drop - the book has this exact example, and says that P1 - P2 = (D_fluid [water] - D_liquid [mercury])*g*H However, I don't understand why the pressure drop isn't just: D_mercury*g*H 3. The attempt at a solution Using the book's guided steps: V2 = (A1/A2)*V1 P1 - P2 = (1/2)*D_water*((A1/A2)^2-1)*V1^2 (1/2)*D_water*((A1/A2)^2-1)*V1^2 = (D_water - D_mercury)*g*H v1 = 0.7875m/s v1 = 78.75cm/s Flow = 78.75 * pi * (10cm/2)^2 = 6185 cm^3/s 6185 cm^3/s * ([1 L/s] / [1000^3 cm^3/s]) = .03825 L/s This is off everyone's favorite online homework system, WebAssign, and I have used 5/6 submissions I'm terribly sorry for the awful formatting, but I don't have access to a good typesetting program as of yet (downloading TeX as we speak [well... as I type]).