In the figure I show a small segement
of a larger truss leaving out completely how many members are attached
to the joints labelled 1,3, and 4. All members connected to joint 2 are shown
The two features to look out for are :
In such a case the third member (here member 24) is a zero-force member, that
- a joint with only three members attached (here the joint 2 ).
- two of the members are aligned (here member 12 and 23).
The reason ? Well, look at the sum of the force on joint 2 in the direction
perpendicular to the two aligned members 12 and 23.
Last revised: Aug 7, 1997