Consider the flow through an orifice or opening in a large tank. The flow is slightly unsteady because the water level in the tank decreases with time, but assume that this effect is small if the tank area is large as compared to the orifice area. Viscous effects are negligible away from the walls of the tank, and all of the streamlines can be traced back to the free surface of the tank. (a) Find an expression for the velocity of the jet at section C-C. (b) Assume that the area of the jet is Ac at section C-C, and find the mass flow rate at this point. (c) If the tank's dimensions are 1m7m1.5m (such that the area of the free surface is 1m7m and the water depth h to the orifice is 1m) and the diameter of the (round) orifice is 5cm, how long will it take to lower the free surface by 20cm