A pair of equal and opposite forces that cause rotation of a body is known as?

A pair of equal and opposite forces that cause rotation of a body is best described as a couple. In mechanics, a couple consists of two forces that are equal in magnitude, opposite in direction, and not collinear. This specific arrangement generates a turning effect or torque about an axis, resulting in rotation of the object. The forces do not create any net translational motion because they are balanced; instead, their effect is to produce a rotational movement.

Understanding couples is crucial in mechanical design because they are often used to analyze systems that need to rotate, such as gears, levers, and various machines. The concept emphasizes the importance of force application points and distances between them, which influence the torque generated—a critical factor for determining the efficiency and function of rotational systems.

The other options do not represent this concept appropriately. Centroid refers to the geometric center of a shape; equilibrium denotes a state where forces are balanced without causing motion, and vector refers to a mathematical quantity that has both magnitude and direction. Each of these terms relates to aspects of physics and engineering, but they do not specifically describe the phenomenon of rotational motion caused by a pair of forces like a couple does.