1. Water at 20C flows through a very long galvanised iron pipe with an internal roughness height of 0.15 mm. (a) The pressure drop along a 75 m long horizontal section of the pipe is 10 kPa. Find the friction factor f, Reynolds number and average speed of the flow in the pipe if the internal diameter of the pipe is 75 mm. Is the pipe flow laminar or turbulent? State any assumptions you use for solving the problems. [15 marks] (b) The flow moves uphill with a change in elevation of 1.5 m across the 100m length of the pipe. The pressure drop along this length of the pipe is 100 kPa and the average velocity in the pipe is 0.8 m/s. Find the pipe diameter. Is the pipe flow laminar or turbulent? State any assumptions you use for solving the problems. [10 marks]