Frictional Force

When the surface of one object comes into contact with the surface of another, friction is the force that prevents the object from moving. Friction reduces the mechanical advantage of a machine, or, to put it another way, friction reduces the ratio of output to input in a machine. A car spends one-quarter of its energy on reducing friction, which is a significant amount. While the tyres and clutch both contribute to vehicle stability, it is friction in the tyres and friction in the clutch that makes it possible to operate the vehicle. Friction occurs everywhere in the physical world, from matches to machines to molecular structures. It is one of the most significant phenomena in the physical world.

What is the definition of Frictional Force?

In mechanics, frictional force is the force generated by two surfaces that come into contact and slide against one another.

A few factors that influence the frictional force are as follows:

These forces are primarily influenced by the texture of the surface and the amount of force that is used to bring them together.

• The amount of frictional force is influenced by the angle and position of the object in question.
• If an object is placed flat against another object, the frictional force between the two objects will be equal to the weight of the object on which it is placed.
• If an object is pushed against a surface, the frictional force will increase until it exceeds the weight of the object, at which point the object will break.

Calculating the Force of Friction

Calculating the maximum amount of friction force that a surface can exert on an object is simple when using this formula:

F_FRICTION = µ • F_NORMAL

In order to assist you in calculating the frictional force, one can use the following methods.

1.Find the Normal Force in your situation.

An object in contact with another stable object experiences a normal force, which is a support force that is exerted upon it. In the vast majority of cases, the normal force can be simply described by the following formula:

N = mg

The mass of the object is represented by the letter m, and the acceleration due to gravity is represented by the letter g. In the case of an inclined surface, the strength of the normal surface decreases proportionally to the amount of inclination of the surface; as a result, the formula becomes:

N = mg cos(θ)

The angle at which the surface is inclined is represented by the symbol. In a straightforward calculation, the normal force of a 2-kg block of wood resting on a surface would be calculated as N = 2 kg x 9.8 N/kg = 19.6 N, where N is the mass of the block of wood.

2.Finding the Right Coefficient

In this case, the coefficient that you would choose would be determined by the object and the situation. If the object under consideration is not moving across the surface, the coefficient of static friction is used; however, if the object under consideration is moving across the surface, the coefficient of sliding friction is used. The coefficient is also affected by the type of materials that are used. Consider the following scenario: A block of wood is placed on a brick surface and the coefficient is 0.6, whereas it is placed on a block of clean wood and the coefficient is between 0.25 and 0.5.

How to Calculate Frictional Force

As previously stated, the formula for frictional force is given by the equation F = μN.

Lets understand the concepts better with the help of an example. 

Consider the case of a 2-kg block of wood that is resting on a table and is about to be pushed away from its resting position. In this case, the static friction coefficient is taken into consideration. The static coefficient of wood is equal to 0.5.

As a result of the information provided, we can calculate the normal force as N = 2 kg 9.8 N/kg = 19.6 N. The frictional force can now be calculated using the values of normal force and static friction coefficient that we have obtained.

F = 0.5 × 19.6 N = 9.8 N

Is there a difference between different types of frictional force?

Yes, there are various types of frictional forces to consider. Friction that occurs between solid surfaces is classified into four types: static friction, kinetic friction, rolling friction, and sliding friction. Foam friction is the term used to describe the friction that occurs between fluids and gases in a closed system. As a result, friction can be broadly classified as follows:

• Dry Friction
• Static Friction
• Kinetic Friction
• Rolling Friction
• Sliding Friction
• Fluid Friction

Let’s discuss some types of frictions that we encounter in our day to day life. 

Dry Friction

While kinetic friction describes the reaction between two moving solid bodies, dry friction describes the reaction between two stationary solid bodies when they are not in motion (static friction). The amount of static and kinetic friction between two solid bodies is proportional to the normal force exerted between them. Different coefficients of friction are used to model the interaction of different substances with one another. By this, we mean that certain substances have a higher resistance to movement than others when the same normal force is applied to them in the same direction. Each of these values has been determined through experimental means.

Kinetic Friction

The most basic definition of kinetic friction is: the resistance to motion caused by contact between a surface and an object moving against it. The force of kinetic friction acts to oppose the motion of the object, so pushing something forward causes friction to push it backwards.

The kinetic friction force, also known as sliding friction, only applies to moving objects (hence the name “kinetic”). This is the force that opposes sliding motion (pushing a box across floorboards), and this and other types of friction have different coefficients of friction (such as rolling friction).

Conclusion

Frictional force is the opposing force that is created between two surfaces when they are attempting to move in the same direction or when they are attempting to move in the opposite direction. The primary function of a frictional force is to create resistance to the motion of one surface over the other surface when two surfaces come into contact.