$3.($a$).$ State FOUR assumptions in the theory of simple bending

$(2$ Marks$)$

$($b$).$ Fig Q$3$ shows the elevation and section of a loaded beam, determine the maximum allowable load wKN$/$M that can be applied to beam if the bending stresses are limited to $90\backslash (\backslash$mathrm$\{$N$\}/\backslash$mathrm$\{$mm$\}^\{2\}\backslash )$ and $\backslash (150\backslash$mathrm$\{$~N$\}/\backslash$mathrm$\{$mm$\}^\{2\}\backslash )$ in compression and tension respectively.