4.36 A sand with G₁ = 2.66 and e=0.60 is completely dry. It then becomes wetted by a ris- ing groundwater table. Compute the unit weight (lb/ft3 or kN/m³) under the

following conditions: (a) When the sand is completely dry. (b) When the sand is 40% saturated (S = 40%). (c) When the sand is completely saturated.