Water at 20 degrees flows at a velocity of (V =) 2 m/s in a (D =) 250-mm diameter horizontal ductile iron pipe. Estimate the friction factor f in the pipe, and state whether the pipe is hydraulically smooth or rough. Compare the friction factors derived from (a) the Moody diagram and (b) the Colebrook equation. Estimate the change in pressure over (L =) 100 m of pipeline. How would the friction factor and pressure change be affected if the pipe is not horizontal but 1 m lower at the downstream section?