Hi, I am a first year studying mechanical engineering and I am having trouble understanding bernoulli equation. This is the first question in the tutorial and I can't seem to get the right answer. Water flows through the pipe contraction shown in the figure below. For the given 0.2 m difference in manometer level, determine the flowrate as a function of the diameter of the small pipe, D. (Ans: 1.56D2 m3/s) From the solution given by my lecturer, it says that z1 = z2 .. this will probably sound really stupid but what height does z actually represent? I know that there is a stagnation point at the pitot tube coming from the manometre so this means that v1 = 0 .. is that correct? The solutions also say that p1 = [itex]\gamma[/itex]h1 .. how can this be? I thought that pressure = Force x Area? If someone could explain the answer to me it would really help a lot. Thanks!