A person is standing in an elevator which is moving down in constant speed. What is the correct relation between contact force, the weight of the person and the net force:

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.