How to use the moment-of-momentum equation for water flowing through a pipe?

Question

I am having a lot trouble understanding this problem, I don't even know where to begin or how to articulate my difficulties, but I will try my best.

1. Is the question asking to find the torque developed at the part in the picture where it says "Pipe supported by wall"?
2. What is meant by the "Horizontal section" of the pipe? In the solution it says that it's going 24 in. into the paper. Okay, so what? Is water flowing through there? I thought it was flowing through the pipe supported by the wall. Or is it flowing through both the pipe support by the wall AND the pipe section that's going 24 in. into the paper?
3. In the solution, I don't understand how the moment arm for the inlet flow is zero and the moment arm for the outlet flow is 24 in. Where is this being measured from? I thought it was being measured from the "Pipe supported by wall"? Where is the force being applied?

I apologize for my extreme confusion. I will be extremely thankful for any help that I can get.

Answer 1

This pipe's bends and the flow of water in it create two reactions:

1- momentum on the wall support created by the first 90 degree elbow, which is not asked for in the question.

2- torque created by the out flow downward which is being asked and answered by the question.