The centrifugal pump impeller in the figure has backward-curved vanes with outlet angle β_{2} = 30° (measured from the backward tangent, as in the velocity triangle). Water enters radially. The outlet diameter, outlet width, speed, discharge and manometric head are marked on the figure; neglect vane thickness. Determine (a) the work done by the impeller per kg of water (answer in J/kg), (b) the theoretical (Euler) head (answer in m) and (c) the manometric efficiency (answer in %).