What is rolling friction?

Rolling friction is a resistive force experienced by an object when it rolls over a surface. Rolling friction slows down the speed of the rolling object. A good example of rolling friction would be the rolling of a football on a lawn. The application of rolling friction can be seen in stroller bags.

Mechanism of rolling friction
The direction of rolling friction

Synonyms of rolling friction

  1. Rolling resistance
  2. Rolling drag
  3. static rolling friction
  4. Kinetic rolling friction
  5. Force of rolling friction
  6. Rolling frictional force

How is rolling friction caused? 

When a force is applied, the object will not initially move due to static friction. After the force applied exceeds static friction, the object starts to roll over the other surface.

Rolling friction is dependent on the elastic deformation of the rolling object. No object is perfectly round, smooth, or elastic. When an object rolls, it undergoes elastic deformation. a small area comes into contact with the surface and gives a resistive force that reduces the speed of the object, this is called rolling friction.

How is rolling friction different from sliding friction?

In rolling friction, surfaces don’t slide against each other but roll over each other. In the case of sliding friction, the two surfaces slide over each other.

Rolling friction and sliding friction
Do wheels reduce friction?

Rolling friction is generally less than sliding friction.

What is the coefficient of rolling friction?

The formula for rolling friction: f=μrN

Where f = rolling frictional force

μr= coefficient of rolling friction

N= normal force

The coefficient of rolling friction is a constant, which shows the measure of the force required for rolling to occur. The lower coefficient of rolling friction shows that less amount of force is required for rolling. It can also be defined as the ratio of rolling frictional force to the normal force.

What are the factors affecting Rolling friction?

  1. The smoothness of the object: Irregularities in the surface will cause interlocking. Smooth surfaces reduce rolling friction. You can read more in this post on factors affecting friction. The surface can be smoothed by grinding or polishing.
  2. Elastic deformation of the object: Elastic deformation of an object increases the area in contact with the rolling surface thus inducing a resistive force. More deformations will increase rolling friction. Metals rolling surfaces have very less elastic deformations but are heavy and thus have high rolling friction. A perfectly round surface will also help in reducing rolling friction. You can read this post for more details on methods to reduce friction.
  3. Load of the object: Friction is always directly proportional to the load/weight of the object. So heavy objects will have higher rolling frictional force.

How can we reduce rolling friction?

  1. Ensure the smoothness of the rolling surfaces. This can be done by grinding or polishing.
  2. The rolling object should be as round as possible. [imagine car]
  3. Use materials wisely. Rubber can be used instead of metals that are heavy.
Imagine this: Rolling friction depends on shape of the object. A perfectly round object will have least friction
Imagine this: Rolling friction depends on the shape of the object. A perfectly round object will have the least friction

What are the examples of rolling friction?

  • Basketball rolling on the ground
  • Car moving on wheels
  • Strolley bags with wheels
  • bullock cart
  • Rolling of Ball bearings
  • Roller Skates
example of rolling friction
Roller skates are a good example of rolling friction

What is the weakest friction?

Friction can be classified as dry and fluid friction. Fluid friction is always weak than dry friction. Dry friction can be classified as static friction, kinetic friction, and rolling friction. Rolling friction is the weakest friction. So the order is like this: Static friction > Kinetic friction > Rolling friction > fluid friction

Why rolling friction is the weakest friction?

In the case of rolling friction, there is no sliding. The surface of contact is very minimal. But in other types of friction, there is complete sliding of objects over one another. If the rolling object is perfectly rigid and perfectly round then the surface of contact is almost zero. The friction proves a torque effect that makes the object roll rather than slide.

What are the advantages of rolling friction?

  1. It reduces the effort involved in moving objects. Stroller bags and conveyor belts are good examples where heavy objects can be moved with much ease.
  2. A comfortable ride in vehicles. If the wheels of vehicles were based on sliding friction, then the ride would be very tiresome.
  3. Speed. Roller skates enable us to move at much faster speeds compared to our shoes due to rolling friction.

What are the disadvantages of rolling friction?

  1. Lack of control. There will be speed when rolling friction comes into action. But, there will also be a reduction in control and maneuvering capabilities. It is much easier to turn with our shoes than with roller skates.
  2. Unwanted accidents. Since rolling friction is less than sliding friction, it is difficult to walk on surfaces will rolling objects.

What is the difference between rolling and sliding friction?

Rolling frictionSliding Friction
The object rolls over a surfaceThe object slides over a surface
The rolling object is generally spherical in shapeNo specificity in shape
Depends on the elastic deformation of the objectNo dependence on elastic deformations
Value of rolling friction is less compared to sliding frictionThe value of sliding friction is greater
Coefficient of rolling frictionCoefficient of sliding and kinetic friction

Is rolling friction static friction or kinetic friction?

Static friction occurs when an object is at rest. Rolling friction occurs when an object is rolling or in other words is in motion. So yes, Rolling friction can be considered kinetic in nature.

What is quantum rolling friction?

Quantum rolling friction is a very new type of rolling friction defined by quantum scientists. It deals with the movement of quantum particles and the frictional forces opposing the motion. You can read more about quantum friction here.

See also:

Research

Tungsten nanorods are generally used as additives because of their good wear-resistant properties. Nanomaterials have unique properties due to their high aspect ratios. In this paper, the authors study the rolling friction and sliding friction properties of the nanomaterial and explain the study of the wear resistance property of WSe2 nanorods. Liink:https://nanoscalereslett.springeropen.com/articles/10.1007/s11671-008-9183-8

Vibratory conveyors are widely used in manufacturing plants like food processing and other raw material processing plants. They are used to feed raw materials to equipment under a vibration state. In this, the authors study the impact of operative parameters like rolling friction on performance. Link: https://www.mdpi.com/2076-3417/10/6/1926