～～ＦＲＩＣＴＩＯＮ～～

The mechanism of friction is rather complex. In simple terms, when a body is at rest, there exists strong adhesive force between molecules of the object and molecules of the rough plane on their contact surfaces . The object and the plane can be considered in the sense as somewhat [fused] together. Thus a stronger force is needed to break the [fused surfaces] on starting the object in motion.

When the object is moving, [fusion] of the surfaces is not easy. That is, the interaction of the adhesive force between molecules of the object and plane on the point contact is not as strong as when the object is at rest. Thus this gives rise to a smaller kinetic frictional force.