$[$ANSWER $11-7$A please$]$

$11-7.$ What is the total active earth pressure per foot of

wall for the retaining wall in Problem $11-4,$ with an

angle of wall friction between backfill and wall of

$25,$ using Coulomb theory? answer found: PA $=6862\mathrm{.}5$ lb$/$ft$=6\mathrm{.}9$ k$/$ft$.$

$11-7$a$.$ Assume that the base of the wall is $4$ feet wide, and the

wall is constructed of reinforced concrete $($unit weight

of $150$ pounds per cubic foot$).$ Using the same angle

of friction between the backfill and the wall as the

friction between the bottom of the wall and the

underlying soil $($assume the same soil parameters

shown in Figure $11-39),$ determine the Factor of Safety

of the Retaining Wall for SLIDING and

OVERTURNING.