Question $2$: Consider an axially loaded elastic beam$-$column as shown in the figure below. It

has constant flexural rigidity of $EI$ and length of $L.$ This beam$-$column is fixed at one end and

its rotation and translation are restrained at the other end. Determine the buckling load $P_{cr}$ by

using the equilibrium method $($hint: the left half of the beam$-$column can be isolated to establish

a moment equilibrium equation$).$