Not really a hw problem, but I'm having a hard time with this section. It's mostly dealing with the horizontal component of the force. This is from my book, Fluid Mechanics by frank m white 5 th ed, "The horizontal component of force on a curved surafce equals the force on the plane area formed by the projection of the curved surafce onto a vertical plane normal to the component." From the book and lecture, I come to the conclusion that I'm looking at the projected area from a top view or looking straight down from above? This idea has worked well with most of my homework problems until i saw this figure: [img=http://img166.imageshack.us/img166/2269/fluidgs5.th.png] For this one i thought the projected area was just a square that was 3m wide and 4m high. The way they did the solution shows that they projected the area to the right as if you are viewing the gate from the left.