$5\mathrm{.}12-7$ A palm tree weighing $5kN$ is inclined at

an angle of $60($see figure$).$ The weight of the tree

may be resolved into two resultant forces: a force

$P_1=4\mathrm{.}5kN$ acting at a point $3\mathrm{.}6m$ from the base

and a force $P_2=500N$ acting at the top of the tree,

which is $9m$ long. The diameter at the base of the

tree is $350mm.$

Calculate the maximum tensile and compressive

stresses ${}_t$ and ${}_c,$ respectively, at the base of the tree

due to its weight.

PROBLEM $5\mathrm{.}12-7$