1. The problem statement, all variables and given/known data Two tanks are connected via a capillary pipe, with one tank over the other. The speed in which the liquid flows from the upper tank to the lower tank is 3472 cm/min. The height of the liquid inside the upper tank is 30cm from the bottom of the tank. The capillary pipe sticks 3cm down into the liquid of the lower tank, and the length of pipe between the two tanks is 35cm. (total pipe length 35+3=38cm) The density of the liquid is 1000 kg/m3, and the viscosity is 1cP. Find the diameter of the capillary pipe. (Hint: Assume laminar flow in the pipe, f=16/Re, but check that this assumption is correct) 2. Relevant equations Not quite sure. 3. The attempt at a solution I assumed that it was as simple as putting in Bernoulli equation, but I cant seem to solve it that way, and I dont see how I can involve the diameter of the pipe as an unknown... Looking for a push in the right direction here.