A timber post square in section has $150$ mm sides has two steel plates $150$ mm

x $6$ mm bolted to it on opposite sides along the entire length. If E for steel is

$205$ kN$/$mm$2$ and E for timber $8200$ N$/$mm$2,$ calculate:

a$)$ The stresses in the timber and steel due to a vertical axial load of $350$

kN$.$

b$)$ If the post is $3$ m high calculate the amount of shortening$$under$$the$$load