A beam with width, $b=10,h={24}^{\text{'}\text{'}},d={21\mathrm{.}5}^{\text{'}\text{'}},$ is monolithically constructed with the column that supports it$.$ The loads are applied on the top of beam as uniformly distributed downward load. The critical section for shear design of the beam is taken at a distance $$ ft from the face of the face of the support. Explain the reason for the chosen location of critical section. please solve correctly