Given a simply supported rectangular frame made of slender beams with a distributed load acting in the vertical direction on the horizontal beam $CD$ with constant intensity $p.$ The beams are linear elastic with constant bending stiffness El$.$ The dimensions of the frame are given in terms of $a$ as shown in the figure.

Use the force method to determine the internal moment in the upper left joint C$.(5$p$)$

Determine the reactions. $(1$p$)$

Determine and draw the moment distribution and the magnitude and location of the maximum moment. $(2$p$)$

Determine and draw the distribution of the normal and shear forces. $(2$p$)$