Laws of friction kinetic friction

Friction resists the relative motion or likelihood of relative motion of two solid surfaces, liquid layers, and solid components as they move against each other. It works in a tangential relationship with the contact. Friction exists in groups at all times. Friction is caused by irregularities in surfaces, according to microscopic examination.

Friction is indispensable for providing traction and facilitating movement on the surface. For accelerating, braking, and changing direction, most ground vehicles depend on friction. Sudden grip loss can result in a loss of control and a crash.

Types of Friction 

Friction can be divided into two types:

Internal Friction: At the moment of deformation, internal friction prevents movement between the elements that make up solid material. 

External Friction: It occurs when two bodies in touch with each other have a propensity to move or are moving relative to one another.

Friction can take several forms, including dry friction, Fluid Friction, lubricated friction, and skin friction. Friction between fluids Fluid friction is a phenomenon that occurs when friction occurs between layers of viscous fluids that are flowing with one another. When a lubricating fluid is present between two solid surfaces, lubricated friction occurs. When a force prevents fluid from moving across the surface of a body, it is called skin friction.

Laws of Friction

The following are the five laws of friction:

• The friction between the moving object and the normal force is proportionate and perpendicular

• The object’s friction is determined by the characteristics of the surface it comes into contact with

• Friction exists regardless of the area of contact as long as there is one

• Velocity does not affect kinetic friction

• The static friction coefficient is higher than the kinetic friction coefficient

Dry friction:  is caused by the lack of lubrication. Static friction is the most common type of dry friction. Kinetic friction occurs when there is too much lubrication and causes the surface to stick together.

Static Friction: Static friction is an opposing force that slows down objects. When there is no friction, it doesn’t matter what you do. There is no limit to how fast something can go. Static friction is represented by the letter fs. Static friction opposes movement, but if there is no friction, then nothing happens. Limiting friction means that there is a maximum speed that something can reach.

The following is a description of the value of static force:

0 ≤  fs  ≤ flimiting

Flimiting = μsN

μs is the coefficient of friction that is a characteristic of the contacting materials that is determined empirically.

N is the normal force exerted on each other by each surface, which is parallel (normal) to the surface.

Static Friction Laws

1. The extent of the highest point. The static friction force between two surfaces is irrespective of the contact area between them.

2. Because the maximum force is related to the normal force, the maximum external force that the object can withstand without moving increases as the normal force increases.

Limiting Friction

This is the maximum force of static friction, which is obtained when a body first starts moving over the surface of another body when they are in touch. Its value is determined by the following equation: Flimiting =   μsN

Limiting Friction Laws

Four laws govern limiting friction:

 1. The typical reaction is precisely proportional to the force of limiting friction between two objects: N & F As a result, if a body is heavy, the usual reaction, i.e. mg, increases, resulting in greater force being required to move the heavy body than a lighter body. 

2. The direction in which one thing is about to move over another object is always the opposite of the direction in which limiting friction is applied.

 3. The force of limiting friction is independent of the distance between two bodies in contact.

 4. The type of the material or the roughness and smoothness of any two items in touch determines how much friction is generated.

Kinetic Friction

It occurs when two moving surfaces collide or when motion is present. The actual motion begins when the applied force is somewhat greater than the limiting friction. Kinetic friction describes the force of friction at this point. Its value is constant and independent of relative motion and contact area. It is denoted by the letter Fk. The kinetic friction coefficient Fk is proportional to N. (normal reaction).

Fk ∝ N

Fk = μkN

μk is the coefficient of kinetic friction

Kinetic Friction Laws

The four laws of kinetic friction are as follows: 

1. Kinetic friction resists relative motion at all times and has a constant value. The nature of the two surfaces of the items in contact determines their value.

 2. Because the value of kinetic friction fk is independent of the contact area, the normal reaction remains constant throughout.

 3. Kinetic friction is not completely determined by velocity. 

4. The normal reaction between the two surfaces in contact is directly proportional to the degree of kinetic friction.

Conclusion 

Friction is the force opposing the relative motion of two solid surfaces. It occurs when there is an uneven distribution of pressure across the surface of the materials. This causes the two surfaces to stick together, causing resistance to movement.The rougher the surfaces, the greater the friction. Heat is produced by friction.

Friction is an important concept of physics. Friction is used to heat and ignite matchsticks, and it is also used in automobile brakes. It is governed according to the laws of friction. There are two significant types of friction.