6) Two open reservoirs are connected by three galvanized iron pipes in series:

L1=300m,D1=200mm; L2=400m, D2=300mm; L3=1200m, D3=450 mm. If the flow is 400

m³/h of water (u=1 cP, p= 1000 kg/m³), determine the difference in elevation of the reservoirs. Neglect any minor friction losses. Use the Moody diagram to solve this

problem.