Torque (of a couple) refers to the rotational force or moment that is produced when two equal and opposite forces act on a body but do not intersect with each other. It is a measure of the tendency of a force to rotate an object around a fixed axis.
Torque is calculated by multiplying the magnitude of one of the forces by the perpendicular distance between the two forces. The unit of torque is newton-meter (Nm) in the International System of Units (SI).
The centre of gravity is the point at which the entire weight of an object can be considered to act. It is the point where all the gravitational forces are balanced, and the object will remain in equilibrium if suspended from this point.
The lower the centre of gravity of an object, the more stable it is. This is because the lower the centre of gravity, the smaller the distance between the centre of gravity and the base of support, reducing the chances of the object toppling over.
In a couple, the two equal and opposite forces acting on a body produce a torque that rotates the object around its centre of gravity. The distance between the two forces determines the magnitude of the torque, and the centre of gravity determines the point around which the object will rotate.