1. The problem statement, all variables and given/known data Water (η = 1.00E-3 Pa·s) is flowing through a horizontal pipe with a volume flow rate of 0.0125 m3/s. As the drawing below shows, there are two vertical tubes that project from the pipe. Assume that H = 0.0458 m and L = 0.738 m. Calculate the radius of the horizontal pipe. 3. The attempt at a solution I've seen this problem posted on this website before, but the solution there didn't work for me. I know you should use Poiseuille's Law, but what do you do about the pressures?