Question

Two- and three-force members are two particular types of members that occur frequently in structures. Two- and three-force members play an important role insimplifying the analysis of structures in equilibrium.

• Two-Force Members: A two-force member is an object in equilibrium on which forces act at exactly two points. Because the object is inforce equilibrium, the resultant forces acting at the two points must have equal magnitudes and opposite directions. And because the object is in momentequilibrium, the two resultant forces must be collinear (i.e., they act along the same line of action).

• Three-Force Members: A three-force member is an object in equilibrium on which forces act at exactly three points. For the object to bein moment equilibrium, the three resultant forces acting at the three points must be either concurrent or parallel.

Identify the two- and three-force members in the following figure. Consider only the members labeled AB and assume that is the load's magnitude.

(Each case should be either labeled as Two-Force Member, Three-Force Member, or Neither)

Answer 1

d,e= two force members
f,b,a= three force members
c= neither