Water drains from a catch basin (with negligible water depth) through a 20-cm diameter, 40 m long concrete pipe flowing full with a surface roughness of 1.2 mm and a downward slope of 2o. Determine the flow rate (volume flow rate) of water from the catch basin. Assume the pressure at the pipe inlet is atmospheric pressure.
(Hint: Start by solving the energy equation for velocity, assume a friction factor, and calculate your initial guess for velocity.)