Can someone please explain to me how it is that member FG is a zero force member? Isn't the only way for a member to be zero force if 1. Two non collinear members form a joint and no force is being exerted on this joint. or 2. When three members form a truss joint for which 1 member is joined at an angle with two collinear members and no force is exerted on this joint. Member FG does not satisfy either of these.