When a single force can be replaced by two equal and opposite forces separated by a distance, the system is called a

When a single force can be replaced by two equal and opposite forces separated by a distance, the system is called a

• A. Resultant
• B. Composition
• C. Couple
• D. Graphical

Answer: (C)

A force couple is formed when two equal and opposite forces act parallel to each other and are separated by a distance. This arrangement creates a pure moment (torque) that causes rotation without any net translational force, because the forces cancel each other out. The moment of a couple is the product of the force magnitude and the perpendicular distance between their lines of action, and this moment is the same no matter where you consider the origin. That’s why this system is specifically called a couple: it produces rotation with zero resultant force. Other terms don’t capture this situation as precisely. A resultant describes the net force, which would be zero here and doesn’t convey the rotational effect. Composition is a general idea of combining forces without describing the special effect of a couple. Graphical isn’t a standard term for this concept.

A force couple is formed when two equal and opposite forces act parallel to each other and are separated by a distance. This arrangement creates a pure moment (torque) that causes rotation without any net translational force, because the forces cancel each other out. The moment of a couple is the product of the force magnitude and the perpendicular distance between their lines of action, and this moment is the same no matter where you consider the origin. That’s why this system is specifically called a couple: it produces rotation with zero resultant force.

Other terms don’t capture this situation as precisely. A resultant describes the net force, which would be zero here and doesn’t convey the rotational effect. Composition is a general idea of combining forces without describing the special effect of a couple. Graphical isn’t a standard term for this concept.