For the same propped cantilever shown below, when a distributed load $w=\frac{P}{L}$ is applied instead, the bending moment $M_A$ will be smaller. Use reaction at $B$ as the redundant force to show $M_A=w\frac{L^2}{8}=P\frac{L}{8}.$

For full credits, follow the steps below:

Find DSI, $DS{I}_e,$ and $DS{I}_i.$

Choose $R_B$ as the redundant force.

Draw the primary structure.