Air at standard conditions flows through an 8-in.- diameter, 14.6-ft-long, straight duct with the velocity versus pressure drop data indicated in the following table. Determine the average friction factor over this range of data.
Q35
Water flows through a horizontal 60-mm-diameter galvanized iron pipe at a rate of 0.02 m3 /s. If the pressure drop is 135 kPa per 10 m of pipe, do you think this pipe is
(a) a new pipe,
(b) an old pipe with a somewhat increased roughness due to aging, or
(c) a very old pipe that is partially clogged by deposits? Justify your answer.