Analysis We take the elbow as the control volume, and designate the entrance by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of flow as being the positive direction) and the vertical coordinate by z. The continuity equation for this one-inlet one-outlet steady flow system is Noting that kg/s. 4.35321===mmm&&&AVmρ=&, the mass flow rate of water and its outlet velocity are