State four properties of couple
Answers
In mechanics, a couple refers to two parallel forces that are equal in magnitude, opposite in sense and do not share a line of action.
A better term is force couple or pure moment. Its effect is to create rotation without translation, or more generally without any acceleration of the centre of mass. In rigid body mechanics, force couples are free vectors, meaning their effects on a body are independent of the point of application.
The resultant moment of a couple is called a torque. This is not to be confused with the term torque as it is used in physics, where it is merely a synonym of moment.[1] Instead, torque is a special case of moment. Torque has special properties that moment does not have, in particular the property of being independent of reference point