A U-shaped irrigation canal is dug into the ground such that the bottom of the channel has a semi-circular cross section with a diameter of 2.0 m. A sluice gate having an overall height of 5 m can be lowered vertically into the channel to block the flow of water. Water partially fills the channel up to the horizontal line B-B. Determine the moment exerted by the water about the line A-A at the upper edge of the sluice gate. Problem