$($a$)$ If end displacements in the local coordinate system for member $9$ of the truss shown are

u$9=[17\mathrm{.}6,3\mathrm{.}2,33,6]$in calculate the axial force in the member.

$($b$)$If the end displacements in the global coordinate system for member $9$ of thr truss shown are

v$9=[16,-8,30,-15]$mm cakculate the forces for the member in the global coordinate system. Is the member in equilibrium under these forces?

$($c$)$ Solve part $($b$)$ using the member stiffness relationship in rhe global coordinate system, F$=$Kv$.$