PROBLEM $4(20$ marks$)$

Truss system consists of straight members joined together with pins, and all supported

with a hinge $($left$)$ and a roller support $($right$).$ The truss system loaded with forces at

the nodes as shown in Figure $4.($a$)$ Calculate the internal forces in the members AB$,$ IJ

and HI$?($b$)$ State which of those members are in tension, and which are in

compression?

Figure $4$: Truss system with external forces at the pinned ends.