What and how does the friction force depend?
With some movement of one body on the surface of another, the so-called friction force arises. A special feature is the direction – it is always the same, in the opposite direction from the direction of movement. This force depends on the surface of the material, on its properties, as well as on the electromagnetic interaction between the contacting bodies.
Friction can be both external and internal. External is when two bodies move relative to each other (rigid bodies). Internal friction occurs when parts of a gas or liquid move from one part to another. Also, friction is divided into dry and liquid. The first occurs when solids interact and when there is no lubrication. Liquid or in other words viscous – the friction of a solid and a gas or liquid medium. Mixed friction is also distinguished – there are surface areas of both dry and liquid friction.
Types of friction forces:
sliding – when one body moves along the surface of another and arises in the opposite direction;
rolling – occurs when one body sways relative to another;
rest – prevents movement and the beginning of movement at rest;
spinning – occurs when one body rotates (rotates) relative to another, the direction is opposite to the side of rotation.
The main characteristic for a given force is the coefficient of friction, which directly depends on the material of the bodies in contact with each other. This coefficient is usually less than one. The branch of physics dealing with the study of the friction force, its types and dependencies is mechanics.
