The beam shown below is subjected to vertical loading that leads to moment about the horizontal axis. Use $f_c=3000$ psi and $f_y=60,000$ psi. Do the following:

a$.$ Verify that the steel centroid is located at $6\mathrm{.}21$ "from the left side of the bream stem if the bars are spaced equally at $\frac{11}{4}($clear spacing$),$ #$4$ stirrups are used and $\frac{11}{2}$ clear cover is provided.

b$.$ Determine the location $($ X and Y values$)$ of Whitney equivalent block $($yellow shaded area.

c$.$ Explain why the line joining the centroids of the compressive and tensile forces must be vertical.

d$.$ Compute the moment capacity of the section.

e$.$ Check if steel yields.