Hydrostatic Pressure in Bent Water Pipe · CAP 2009 #2
Physics · fluid-mechanics
Problem
A tap water pipe is bent as shown in the diagram. Sections 1 and 2 of the pipe are horizontal but section 2 is placed higher at a height of H. The diameter of the pipe of section 1 is 1.5 times larger than the diameter of section 2. Indicate which of the following is the most complete answer for the relationship between the hydrostatic pressures measured by the gauges in sections 1 and 2:
(a) P₁ < P₂ because water flows slower in section 1.
(b) P₁ > P₂ because water flows slower in section 1.
(c) P₁ > P₂ because section 1 is lower than section 2.
(d) P₁ > P₂ because water flows slower in section 1, and section 1 is lower than section 2.
(e) For some value of H, P₁ = P₂ because the lower speed of the flowing water in section 1 is compensated by the hydrostatic pressure due to the difference H in the height of the two sections.