A masonry wall with vertical back has a backfill 5 m behind it. The ground level is horizontal at the top and the ground water table is at ground level. Measured the horizontal pressure on the wall using Coulomb's earth pressure theory. Suppose the unit weight of saturated soil is 15.3 kN/m3. Cohesion = 0. φ = 30°. Friction between wall and earth = 20°