Problem $2.$ Determine the force in the two cables for the plate given below, as well as all reactions at $C,D$ and $E.$ The cables go from $A$ to $C$ and $B$ to $C.$ Coordinates for the points and $z$ are $A(10,0,4),B(10,0,-4),C(-5,3,0),D(0,0,3),E(0,0,-3),$ in feet units. Hinges are provided at $D$ and $E,$ allowing free rotation about the $z$ axis. The applied loading of $500psf($pounds per square foot$)$ is evenly distributed over the whole plate area. Tensile stress in a cable is the tension force divided by the cross$-$sectional area. If the allowed tensile stress of the steel cables is $70$ ksi $($kips per square inch$),$ what cross$-$sectional area is to be used for each cable? If point $C$ is moved up to $y=8$ feet determine the new cable areas and, again, if $C$ is moved down to $y=0\mathrm{.}5$ feet.