Concept:A couple consists of two equal, parallel forces acting in opposite directions along different lines of action.
These forces cancel each other's translational effect, so their resultant force is zero.
Explanation:Consider the two forces that form a couple: they have equal magnitudes, say
F1 and
F2, but act in opposite directions.
Because they are equal and opposite, their vector sum is
F1−F2=0.
This means the forces do not produce any net pull or push on the body.
Therefore, the resultant force of the couple is zero.
It is important to note that although the resultant force is zero, the couple still produces a turning effect.
This turning effect is the moment of the couple, calculated as the product of one force and the perpendicular distance between the two forces.
The moment is nonzero, but the resultant force itself remains zero.
Hence, among the given options, the correct choice is the one indicating zero.
Answer:The resultant force of a couple is Zero, so the correct option is B.