Sliding Friction

The resistance force created when two bodies slide against each other is known as sliding friction. This friction, also known as kinetic friction, is described as the force required to keep one surface rolling over another. It is dependent on two variables: one is the object’s substance, and the other is its weight and size. The sliding friction is unaffected by changes in the contact surface area. Sliding friction is substantially lower than static friction in most materials.

Sliding is the frictional force caused by the rotating movement of a disc-like or any other circular item along a surface, whereas rolling friction is the frictional force caused by the rotational movement of a disc-like or any other circular object along a surface. The frictional force of rolling friction is often substantially lower than that of sliding kinetic friction. The coefficient of rolling friction is usually smaller than the coefficient of sliding friction. Sliding friction, on the other hand, tends to produce more sound and thermal bi-products.

Sliding Friction Definition

Sliding or kinetic friction is the frictional force that prevents genuine relative sliding motion between two contact surfaces. Let’s start with a basic understanding of frictional forces. If there is a metal block on a table, a weak force may not be enough to move the metal block. The metal block begins to move as you gradually increase the force until it reaches a certain point. The resistive force offered by the metal block in its static form is the same as the controlling value of the force at which the metal block begins to move. Static Friction is the name given to this resistant force. The metal block moves when the force is increased further in the experiment. However, even after the metal block has begun to move, it continues to exert a resistant force in an attempt to stop it. It’s referred to as sliding friction.’ The sliding friction is clearly smaller than the static friction, based on what we’ve defined so far.

The force of sliding friction acts in the direction normal to the surface and is directly proportional to the weight. When the surface on which the body slides is horizontal, the normal force is equal to the weight of the object.

Sliding Friction Formula

The coefficient of sliding friction multiplied by the normal force is the equation for sliding force.

Fs = sFn

Where,

Fs is the sliding friction force.

s = Sliding Friction Coefficient

Fn stands for normal force.

Motion under Sliding Friction

Newton’s Second Law can be used to show motion under sliding friction (in basic systems of motion)

∑F=ma

FE –FK=ma

FE stands for external force.

• When the outside force is larger than the kinetic friction force, acceleration occurs.

• When the force of kinetic friction is greater than the force of the outside force, slowing (or stopping) occurs.

• Because there is a net force on the item, Newton’s first law of motion is also followed.

• When there is no net force on the item, that is, when the outside force equals the force of kinetic friction, constant velocity occurs.

Motion on an Inclined Plane

When a block glides up or down an inclined plane, it can be used to demonstrate friction. The free body graphic below depicts this.

The component of gravity’s force in the inclination direction is represented by:

Fg=mg sin

The normal force (perpendicular to the surface) is depicted as follows:

N=mg cos

As a result, because friction prevents the block from moving,

Fk= k.mg cos

To calculate the coefficient of kinetic friction on an inclined plane, observe that the moment when the force is parallel to the plane is equal to the moment when the force is perpendicular; this occurs when the object is travelling at a constant velocity at an angle.

Fg=mg sin

∑F=ma=0

Fk= Fg or= k.mg cos=mg sin

k=tan

Understanding Sliding Friction

The coefficient of sliding friction produced or generated by objects takes into account numerous aspects that can affect the level of friction. The following are some of the factors that can affect sliding friction:

• The distortion of an object’s surface.

• The surface roughness or smoothness.

• The velocity of either object at its inception. The object’s dimensions and shape.

• The amount of forces applied to an object.

The coefficient of Sliding Frictions

. A frictional force F observed by an object is directly proportional to the normal force N exerted by that object, according to a general formulation. That is to say,

F= μNF

The coefficient of friction is defined as where is a constant. Because it is plainly a ratio of two forces, it has no dimensions. When the friction is static, the coefficient of friction is called “coefficient of static friction” and is denoted by s, but when the friction is sliding, the same constant is called “coefficient of sliding friction” and is denoted by k. The subscript ‘k’ stands for ‘kinetic.’ Then, because sliding friction is always less than static friction,

k< s

Sliding Friction Examples

Because the degree of sliding friction is so great, there are no different examples of sliding friction. Because of chemical interactions, sliding friction between two surfaces produces heat. The quantity of heat created is dependent on the materials of the surfaces and can sometimes result in a fire. Lighting a match stick is an excellent example in today’s environment. To start fires in the Stone Age, men used two stones. Because sliding friction has a large degree of frictional force, it is preferable to place an object on a wheel and carry it rather than pushing it along because the result of rolling friction is significantly less than that of sliding friction. The coefficient of rolling friction is much smaller than the coefficient of sliding friction.

Conclusion

The friction coefficient of a rigid body sliding on a powder layer was measured. This is a concept used to explain why debris avalanches have such a low apparent friction coefficient. Flour was employed as the powder material in the experiment, with metal discs serving as the stiff body that moves over the powder layer.

The state of the disk’s basal surface was altered for comparison. When utilising discs with a rough surface onto which powder particles might attach, low friction coefficients were attained. The critical speed of flotation was not found using discs with flat surfaces because the friction coefficients were too high. For comparison, the powder substance was also altered. When flour or starch was utilised, the discs slid in flotation, but when silica sand was employed, the critical speed of flotation was not detected.

The dynamic pressure model is proposed as the process that generates the force that allows a disc to float. The critical speed calculated using this model agrees with experimental findings.