Water flows with a flow rate of 0.5 cumecs through a pipe AB of length 12 m having a uniform cross-section. The end B of the pipe is above the end A and the pipe makes an angle of 30° to the horizontal. For a pressure of 20 kN / m2 at the end B, the corresponding pressure at the end A (in kN / m2 units) is:
1
137.7
2
38.9
3
78.9
4
71