Question #$4(4$ pts$.)$:

The $1\mathrm{.}5-$foot thick retaining wall in the figure at left has a coefficient of base friction of $0\mathrm{.}49.$ Determine the active earth pressure $($magnitude and location$)$ against the wall, and check the wall for factor of safety against sliding only. Take the unit weight of concrete to be $145pcf.$

Question #$5(3$ pts$.)$:

Determine the required radius $R$ of the circular footing in the figure at right in order to meet a facto of safety of $3.$