Problem $2.$ A gravity retaining wall is shown in Figure $2.$ Calculate the factor of safety with respect to overturning and sliding, given the following data $($Use Coulomb's active earth pressure in your calculation and letting ${}^{\text{'}}=\frac{2}{3}{}_1^{\text{'}})$:

Wall dimensions: $H=6m,x_1=0\mathrm{.}6m,x_2=2m,x_3=2m,x_4=0\mathrm{.}5m,x_5=0\mathrm{.}75m,x_6=0\mathrm{.}8m,D=1\mathrm{.}5m$

Soil properties: ${}_1=16\mathrm{.}5k\frac{N}{m^3},\frac{O}{{?}_1^{\text{'}}}=32,{}_2=18k\frac{N}{m^3},\frac{O}{{?}_2^{\text{'}}}=22,c_2^{\text{'}}=40k\frac{N}{m^2}$

Figure $2$

${?}^{**}$ For both questions, use ${}_{\text{c}\text{o}\text{n}\text{c}\text{r}\text{e}\text{t}\text{e}}=23\mathrm{.}58k\frac{N}{m^3},k_1=k_2=\frac{2}{3},$ and $P_P=0$ as needed.