QUESTION $1$:

For the sections shown above, calculate the following cross$-$sectional properties:

i$.$ Area,

ii$.$ Centroid,

iii. moment of inertia about the centroid.

$A=105mm$

$B=285mm$

$C=850mm$

$D=950mm$

QUESTION $2$:

If each of these sections is loaded with a moment of $150kN.$m$,$ find the stresses at the top and

bottom fibers.

QUESTION $3$:

Find the moment that will cause cracking at the bottom fiber of each of these sections.

Assume a cracking stress of $1\mathrm{.}5$MPa.