2. A venturi meter is used to measure the flow rate through a pipeline. A schematic of the device is given below. The volumetric flow rate is determined from the

pressure difference between a location just infront of the venturi and a location at the throat. (a) Determine the expression of the volumetric flow rate Q as a function of the fluid density p, the pressure difference (Ap = p1 –- p2), and the cross sectional areas A1 and A2 (b) Explain why the pressure difference is taken between 1 and 2, rather than between 2 and 3.Hint:think about the assumptions used to derive the formula for Q.