Question $4$: Continuous cable ADB runs over a small

frictionless pulley at $D$ to support beam OABC that

is part of an entrance canopy for a building as

shown in the figure. Assume that the canopy

segment weights $1850$ lb $.$

a$)$ Find the required cross$-$sectional area of

cable ADB if the allowable stress is $25$ ksi $.$

b$)$ Determine the required diameter of the

pins at $O,A,$ and $BD$ if the allowable stress

in shear is $12$ ksi $.$ Assume that all pins are in

double shear.