3. Consider a rectangular steel plate which is 4 feet long and 5 feet wide (into the page) which is placed in water. The plate is inclined at 30° from horizontal along its length. The top edge of the plate is submerged 3 feet below the water surface. a) Determine the magnitude of the resultant force FR acting on the surface of the plate in pounds. b) Determine the vertical distance in feet from the water surface to the location where the resultant force acts on the plate.

EB and FG are two planes inside a soil element ABCD as shown in Figure 10.50. Stress conditions on the two planes are Plane EB: EB = 25 kN/m2; EB = +10 kN/m2 Plane FG: FG = 10 kN/m2; FG = 5 kN/m2 (Note: Mohrs circle sign conventions for stresses are used above) Given ; = 25, determine: a. The maximum and minimum principal stresses b. The angle between the planes EB and FG c. The external stresses on planes AB and BC that would cause the above internal stresses on planes EB and FG

A 9 ft wide and infinitely long flexible strip load of 800 lb/ft2 is placed on an elastic medium as shown in Figure P8.7. Find the vertical stress increase at points A, B, and C located 3 ft below the surface.