Me podrían ayudar es de física?

Need asap ‼️ 20 pts which gravitational force field diagram is drawn correctly? (answers in pictures below)

Use the profile illustrated for problem (1). assume that the layer of silty sand fill (sm) is placed over the entire site. estimate the thickness of the fill (h - in feet) that will cause the effective vertical stress at the center of the clay layer to increase by 517.5 pounds per square foot.

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.