$9-5.$ A square footing with a size of $8$ ft by $8$ ft is to carry a total load of $40$ kips $.$ The depth of the footing is $5$ ft below the ground surface, and groundwater is located at the ground surface. The subsoil consists of a uniform deposit of soft clay, the cohesion of which is $500l\frac{b}{f}{t}^2.$ The soil's unit weight is $110l\frac{b}{f}{t}^3.$ Compute the factor of safety against bearing capacity failure.