be in equilibrium

always reduce to a resultant force

always reduce to a couple

both (a) and (c)

that polygon of forces must close

that resultant couple must be zero

both that polygon of forces must close and that resultant couple must be zero

none of the above

howe truss

king post truss

fink truss

warren truss

only the closure of force polygon is sufficient

only the closure of funicular polygon is sufficient

both force polygon and funicular polygon must close

none of the above

the resultant force and resultant couple are always zero

the resultant force is zero but resultant couple is not zero

the resultant force is zero but resultant couple may not be zero

the resultant force and resultant couple both may not be zero