1. The problem statement, all variables and given/known data See attached image: 2. Relevant equations p/ρg + V^2/2g + z = constant head loss (major) = f * l/D * V^2/2g 3. The attempt at a solution To use the energy equation while incorporating head loss, I need to determine the velocity in each section of pipe. The problem is I don't know how! I do know that the pressure drop from the tank to the atmosphere is equal to the pressure in the tank.