$(30$ points$).$

Scoring criteria

$1$ Calzulate the reaction force at points B and $D$ is points$)$

$4.$ Calcu'ate the pernendicular force units and draw a pirture ai the distribution of the perpendicular force units $($of at the positions B and

C$.$ respacively. $(5$ points$)$

$5$ Calculale the foree unit and draw a picture of the distribution of the stress unit. $(1)$ Calculate the depth of the cros: section at the position of sels $B$ and $C$ respectively $(5$; poinisi$)$