Problem $1$: Determine $($a$)$ the moment of inertia of the beam's cross$-$section about the horizontal centroidal axis, and $($b$)$ the first moment of the cross$-$section about that axis. Hints: $Q\frac{?}{b}=ar(y{)}^{\text{'}}{A}^{\text{'}},I=b\frac{h^3}{12},I=I_c+A{d}^2$