The linkage is made using two A$992$ steel rods, each having a solid circular cross section. If each rod has a diameter of $2$ in$.,$ determine the largest load it can support without causing any rod to buckle if the factor of safety against buckling is $1\mathrm{.}8.$ Assume that the rods are pin connected at their ends.

Answer: limitation on P due to rod AB : $8\mathrm{.}634$ kip; limitation on P due to rod BC : $7\mathrm{.}369$ kip; overall limitation on P: $7\mathrm{.}369$ kip $6.($adapted from Hibbeler $\backslash (10^\{\backslash$text $\{$th $\}\}\backslash )$ ed$.$ prob. $13-102)$

A rectangular wooden column has the cross section shown. If $\backslash ($ a$=3\backslash )$ in$.,$ determine the maximum column length allowable under the NFPA formulas for each of the following load and end support combinations.

a$.9-$kip centric load, one end fixed, one end free

b$.15-$kip centric load, one end fixed, one end pinned

c$.21-$kip centric load, both ends fixed

Answers: $($a$.)4\mathrm{.}108$ ft ; $($b$.)8\mathrm{.}890$ ft ; $($c$.)5\mathrm{.}500$ ft