$3-$ The beam $-$ column below, which has two ends and

Concentrated load $Q=80KN$ and compressive load $P=100KN$

$E\frac{\text{I}}{L^2}=6$ kilonewtons. Maximum Bending and the displacems

at the location of the concentrated load.

$2-$ It is desirable to check the stiffness of the linear spring in elastic buckling $"C".$

It is attached to the column with two articulated ends as shown below.

and draw the $\frac{P_{cr}}{P_0}$ versus $C\frac{L}{P_0}$ curve.

If $P_0={}^{2}E\frac{\text{I}}{L^2}.$