Cross$-$Section

The figure shows a simple supported beam. Please do the following:

a$)$ Draw a Free$-$Body Diagram.

b$)$ Find reactions.

c$)$ Draw the internal shear and bending moment diagrams.

d$)$ Propose the dimensions of the cross$-$section such that the critical $($maximum in

absolute value$)$ shear and normal stresses are less than $210$ MPa $.$

Hint: You can assume the dimensions of the cross$-$section to compute the normal and

shear stresses. If those stresses are lower than $210$ MPa $,$ your design is OK; otherwise,

you need to increase the assumed dimensions of your cross$-$section and recompute the

stresses. Try to select a cross$-$section that gives you stresses closer to $210$ MPa $.$