My solution is wrong. Use the Navier Stoke equation, the Euler equation, or the Bernoulli equation to find out the answer to the blank. Since you are learning hydrodynamics in college, you assume laminar flow, steady state, and incompressible fluids. I understand that other assumptions are insufficient. Still, I hope you can find out the answer while looking at my solution. And while I was asking this question again and again, everyone only explained the answer in writing, so I hope you can explain each and every one of the solutions in detail. If you don't mind, I$\text{'}$d like a hand$-$by$-$hand solution rather than typing. I$\text{'}$m really desperate because the exam is just around the corner. I hope you make ceaseless efforts. Thank you.