Example $1$:

A two$-$bar mechanism where a tool is attached on point $B$ is such that the approaching direction $($x$)$ of the tool is aligned with the axial direction of the binary bar $AB.$ The positions and lengths of the bars under the global coordinate system $($O$-$XY$)$ are given as $L_1=4in,{}_1=30$ and $L_2=3in,{}_1=60.$ Find the global stiffness matrix of the system in the global coordinate system $($O$,$XY$).$