Background. An important problem in structural engineering is that of finding the forces
and reactions associated with a statically determinate truss. Figure 12.4 shows an example
of such a truss.
The forces (F) represent either tension or compression on the members of the truss. External
reactions (H2, V2, and V3) are forces that characterize how the truss interacts with the
supporting surface. The hinge at node 2 can transmit both horizontal and vertical forces to the
surface, whereas the roller at node 3 transmits only vertical forces. It is observed that the effect
of the external loading of 1000 lb is distributed among the various members of the truss.