# Difference Between Sliding Friction and Rolling Friction (With Table)

Sliding friction and rolling friction are two types of frictional forces that work against an object’s motion across a surface. Friction is a force that prevents adjacent objects from sliding against each other. Rolling friction is more difficult to analyze than sliding friction. The rolling friction is generally lower than the kinetic friction involved with sliding.

## Sliding Friction vs Rolling Friction

The main difference between Sliding Friction and Rolling Friction is that Sliding friction occurs whenever one contact rubs against another, but rolling friction occurs when an entity rolls on another surface. Sliding friction can be classified as a form of friction, but rolling friction is not.

Sliding friction is a simple concept with a lot of applications. We can’t locate a flat finish in real life. Because of the relative velocity between the two adjacent surfaces, when an item slides on any surface, it receives a backward force. Sliding friction has always been the opposite of motion. Whenever we try to slide an object on a flat floor, such as a cabinet, we experience sliding friction.

The creation of the circular wheel is regarded as a watershed moment in human history. The first wheel was born out of the need to roll an object. Rolling friction is a force that resists motion whenever an object rolls on a surface. Ideally, when a thing rolls smoothly on a surface, there is no sliding friction between the surfaces that are in contact. In practice, however, both the body and the surface bend due to elastic properties.

## What is Sliding Friction?

The force of friction between the two objects that are rubbing against each other is known as sliding friction. The presence of tiny bulges on a surface causes sliding friction. The protrusions engage when the two surfaces move against each other, and labor is required to keep the objects moving. We are not working against gravity here, so the resistance we perceive is due to sliding friction.

Furthermore, in a static state, the applied force attempting to slide the item always is equal to the friction acting on it. When we progressively increase the applied force, the item begins to progress in the direction of the external factor at some point.

Sliding can take place between two items of any shape, but rolling friction is the frictional force associated with rotating motion. The coefficient of rolling friction is much lower than the coefficient of sliding friction. It usually produces more acoustic and thermal by-products.

There are certain exceptions, such as metals with different static and sliding friction coefficients and small surfaces where molecule attraction forces take precedence. It is determined by two factors: one is the object’s substance, and the other is its weight. Any increase in the area of contact does not affect the sliding friction.

## What is Rolling Friction?

Whenever the surface of one body rubs against the surface of the other, rolling friction develops. The deflection that develops on the surface when rolling occurs is the source of this force. Hysteria is a major factor: the energy released when surfaces regain their original shape after deformation will be less than the energy used to cause the deformations in the first place.

When compared to sliding friction, it is discovered that rolling friction is substantially lower. For example, the coefficient of sliding friction between dried asphalt and rubber is 0.68, whereas the coefficient of rolling resistance for a road tire is 0.01-0.035. This version of the equation, however, is misleading.

In reality, the “coefficient” is influenced by a variety of different factors. Consider a bicycle wheel on a tarmac. Instead of a contact point, we have such a contact area. The wheel straightens out at the point where it makes contact with the carpet, forming a shallow trench just on the surface.

The force is thus dispersed throughout the contact region, and reaction vectors eventually agglomerate only at trench in opposition to the motion. This notion can also be applied to a training tire on a rail. Steel is less likely to deform than rubber. As a result, the rolling friction of a train wheel is lower than that of a bicycle wheel.

## Main Differences Between Sliding Friction and Rolling Friction

1. Sliding Friction is due to a correlation between the size of tiny bumps on surfaces. As a result of surface deformation, Rolling friction happens.
2. Acceptable sliding friction is one sort of friction. Rolling friction is not a resistive force but rather a type of friction. It’s vital to understand that friction isn’t the only type of resistive force.
3. The coefficient is influenced by the small amount of available warmth and the structure of the surfaces, which is not simply attributable to external factors. The coefficient is influenced by the radius of the rolling item, the depth to which the object lowers, the structure of the surface layer, and several other factors.
4. Sliding friction acts as a continuous external component throughout the contact area to stop relative motion. Rolling friction is a force that creates a reverse torque in an attempt to stop the wheel from rolling.
5. Ball bearings are used to replace sliding friction between the shaft and the wheel in most modern applications. The friction of rolling is substantially lower than that of sliding.

## Conclusion

The force of friction acting between two sliding bodies or surfaces rubbing against each other is known as sliding friction. Once the surface with one body rubs against the surface of another, rolling friction develops. The friction is reduced by rolling the bodies over each other.

The friction increases as the object slides. Consequently, sliding friction always exceeds rolling friction. To stop relative motion, it acts as an external return factor over the entire contact area. Rolling friction is a resistant force, not a form of friction, that attempts to stop the rotational movement by producing a reverse torque.

## References

1. https://www.sciencedirect.com/science/article/pii/S0022489817300721
2. https://aip.scitation.org/doi/abs/10.1063/1.1735043