OUESTION $3(16$ marks$)$

A beam with a cross$-$section shown in Figure $2$ resists a maximum positive bending

moment of $18kNm.$

a$)$ Determine whether the section is over$-$stressed or under$-$stressed if the allowable

bending stresses are $80\frac{N}{m}{m}^2$ in tension and $75\frac{N}{m}{m}^2$ in compression.

b$)$ Determine the maximum moment that the beam can carry so that it is not

overstressed.