Question

Define couple and give 2 examples

Answer 1

A couple consists of two parallel forces that are equal in magnitude, opposite in sense and do not share a line of action. ... For example, the forces that two hands apply to turn a steering wheel are often (or should be) a couple. Each hand grips the wheel at points on opposite sides of the shaft.

Answer 2

Two equal and opposite parallel forces not acting along the same line, form a couple. A couple is always needed to produce the rotation.

For example, turning a key in a lock and turning a steering wheel.