I haven't taken physics in a while, and most of this is physics related. My professor's lectures have not helped me understand the material, so I have questions on my homework. I would like to learn how to approach this problem and solve it. The figure shows a vertical dam holding back a reservoir of depth h. The lower half of the reservoir consists of a sludge whose density is twice that of water, and the upper half of the reservoir's volume consists of pure water. a. Determine how pressure depends on altitude z in the water and sludge. b. Let w be the dam's width, and determine the horizontal component of force on the dam. Thank you in advance.