Prob. $3$

Find the maximum allowable value of $P$ in $MN$ for the given

column. The cross$-$sectional areas and working stresses are shown

in the figure.

$4.$ The homogeneous $7200-Ib$ bar ABC is supported by a pin at $C$ and a

cable that runs from $A$ to $B$ around the frictionless pulley at D$.$ Find the

stress in ksi of the cable if its diameter is $0\mathrm{.}9in.$

$5.$ The $1300-kg$ uniform bar $AB$ is suspended from two

cables $AC$ and $BD$; each with a cross$-$sectional area of

$405m{m}^2.$ Find the location $x$ in $cm$ of the largest

additional vertical force that can be applied to the

bar. The stresses in $AC$ and BD are limited to $0\mathrm{.}1$GPa

and $50,000$KPa, respectively.

$6.$ The column consists of a wooden post and a

concrete footing, separated by a steel bearing plate.

Find the maximum safe value of the axial load $P$ in kip,

if the working stresses are $1\mathrm{.}10$Ksi for wood and

$0\mathrm{.}450$Ksi for concrete. please ans: $4,5,6$