A swimming pool is drained using a hose. The hose has 20 mm internal diameter, a roughness height of 0.2 mm and is 30 m long. The free end of the hose is located 3 m below the elevation of the bottom of the pool. The average velocity at the hose discharge is 1.2 m/s.
(a) Estimate the depth of the water in the swimming pool.
(b) If the flow were inviscid, what would be the velocity of water at the exit of the pipe?