Current Attempt in Progress

A freeway sign measuring $14$ ft by $5$ ft is supported by the single mast as shown. The sign, supporting framework, and mast together

weigh $690$ lb $,$ with center of gravity $13$ ft away from the vertical centerline of the mast. When the sign is subjected to the direct blast of

a $90-m\frac{i}{h}r$ wind, an average pressure difference of $20\mathrm{.}5l\frac{b}{f}{t}^2$ is developed between the front and back sides of the sign, with the

resultant of the wind$-$pressure forces acting at the center of the sign. Determine the magnitudes of the force and moment reactions at

the base of the mast. Such results would be instrumental in the design of the base.

Assume $a=14ft,b=6ft,c=5ft,$ and $d=12ft.$