The figure shows the free body diagram of the tube near the free end B. The load on top of the tube is P which equals 30 kilo newtons directed vertically downwards. The reaction force on member 2 is F subscript 2 directed vertically downwards. The reaction force at the base of the tube is F subscript 1 directed vertically downwards.

Two equations have been derived for the axial structure:

Fy=-F1-F2-30 kN=0

and

F1L1A1E1=F2L2A2E2

With two equations in terms of the two unknowns F1 and F2, these equations can be solved simultaneously to determine the internal forces in tube (1) and core (2).