Friction : Definition,Types and Examples

Introduction

A fundamental force that occurs when two surfaces come into contact with one another is friction. This phenomenon has an impact on almost every aspect of our day-to-day lives, from walking to driving to how machines work. Understanding contact is pivotal in fields going from material science and designing to science and geography. We discuss the definition, origin, significance, and various types of friction in this section.

Understanding friction

What is friction?

Friction – Definition

“The opposing force setup between the surfaces of contact, when one body slides or rolls on the surfaces of another body.”

All surfaces are rough and uneven.Friction occurs due to the rough and uneven surfaces getting interlocked.Opposing force always acts between the two objects.Friction is a force that opposes the relative motion of surfaces in contact.Opposing force depends on the nature of the surfaces of two bodies in contact.

Friction converts mechanical energy into thermal energy.Friction can wear down surfaces causing surfaces to heat up. Friction is responsible for creation of lightning.Friction between tectonic plates can cause earthquakes.

Importance of understanding friction

Understanding how materials behave, how energy is transferred, and how forces act on a moving object is made easier with friction.Friction can be helpful in expanding the efficiency like shoes on a floor, engage  and disengage gears in a vehicle and the created heat in tires heats up the tires  and improves the grip.

We can exert control over objects through friction. We can hold and grasp instruments, compose with pens, and play sports.Friction is essential in modern applications like slowing down and crushing.

What is frictional force?

The justification for the frictional force is because the minute irregularities prompts serious interlocking between infinitesimal knocks on the surfaces of the objects  prompting higher friction.The frictional force goes against the general movement or propensity of such movements. Because of this, skiing on ice is much simpler than skiing on sand paper.

The two principal sorts of frictional force in particular static friction and dynamic friction. Static friction keeps an item from beginning to move when a force is applied. Dynamic friction acts between surfaces that are moving comparatively with one another. Kinetic friction opposes movement once an object begins to move.

Angle of friction

At particular angle of inclination of an inclined plane at which a body placed at rest on the plane is about to slide down.The angle of friction is an important component of the total shear strength of a joint.

Friction in solids,liquids and gases

Friction in solids

• Caused by the irregularities  in the surfaces that interlock
• All the atoms inside a solid produce friction when it is compressed
• Amount of friction depends on materials in contact and the normal force pressing the surfaces together.
• It is the common type of friction
• Example

Friction in liquids

Caused by the  molecules of a liquid collide with each other and also with the walls of the container

• It is the resistance between moving layers of the liquid
• Depends on the temperature of the liquid and the type of liquid.
• Friction in fluid is called viscosity.
• Honey is more viscous than water, and honey has more friction than water.
• Example of fluid friction is the flow of liquid through pipes

Friction in gases

Caused by the collision of gas molecules with each other and with the surfaces of an object moving through the gas.

• It depends on the speed, size of the object and the density of the gas.
• It is called drag.
• Aeroplanes flying

Types of friction

Static friction

Static friction – Definition

Static friction is a self-adjusting force in that it rises as the applied force increases until the item begins to move.(As the surface roughness increases, there is greater interlocking between the surfaces in contact.)

Static friction:Key characteristics

• Static friction is directed. (acts parallel to the surfaces in contact, always acting in the opposite direction of the applied force and opposing the direction of imminent motion).
• The magnitude of static friction changes to match the applied force up to a particular limit. Maximum static friction is obtained right before the item begins to move.
• When the applied force to move the items surpasses the maximum static force friction, the frictional force transforms into kinetic friction.
• Static friction friction is determined by the type of the surface in contact as well as the force applied perpendicular to the surfaces in contact (Normal force), and is independent of the area of contact.

Sliding friction

Sliding friction – Definition

“The force that resists the motion of two surfaces sliding past each other is known as sliding friction.”

Sliding friction – Key characteristics

• Direction : Sliding friction acts in the opposite direction of the relative motion between the surfaces.
• Mechanism : The sliding friction mechanism is caused by the interlocking of imperfections trapped on each other, providing resistance to motion.
• Another name : Kinetic friction is another name for sliding friction.
• Magnitude : The magnitude of sliding friction is determined by the type of the materials in contact and how hard the surfaces are pressed.(depends on the properties of surfaces such as roughness and hardness.
• Comparison : The static friction is always smaller than the sliding friction.In general, sliding friction is greater than rolling friction.
• Example : A block of wood sliding on a table, Car tires skidding in a wet road.

Sliding friction – Applications

• Screws and nails use friction to hold objects together.
• Walking and running rely on sliding friction between shoes and the ground
• Lubricants reduce friction between surfaces, making them   move more easily.
• Brakes use friction to slow down and stop moving objects.
• Writing with a pen or pencil involves sliding friction between the pencil lead or pen tip and the paper.
• Snowboarding relies on controlled sliding friction between the snowboard and the snow.    

Effects of sliding friction

• Rougher surfaces generally have higher sliding friction than smooth surfaces.
• Greater the normal force, the greater the sliding friction.
• Larger the area of contact, the greater the sliding friction.
• Lubrication can significantly reduce sliding friction creating a thin film between the surfaces.

Rolling friction

Rolling friction – Definition

“When one object rolls on another surface the deformation produced is less and the deformation creates a resistance  to the motion.Rolling friction depends on properties of objects and surfaces.”

Rolling friction – Key characteristics

• The magnitude of the rolling friction depends on  weight of the object, softness of the surface  and radius of the object.
• Comparison: The magnitude of the rolling friction is lower than the sliding friction.
• Mechanism: The mechanism of  rolling friction is due to the  deformation of surfaces.
• Examples: Ball rolling on the ground and wheel rolling  on a road.

Friction in physics experiments

Inclined plane experiment

A block is placed on an inclined plane and gradually increases the angle of the plane until the  block starts to slide.The force required to overcome static friction is equal to the weight  of the block multiplied by the  sine of angle at which the block starts to move.

Friction in liquids – Viscosity experiment

Spring balance – Experiment

Attach a spring balance to the hook on the one end of a rectangular block.At first the block remains at rest on account of the force  of friction which is equivalent and opposite to the applied force(pull).

Increment the force on the block by pulling the spring balance which estimates the horizontal force expected to make the block move.The perusing (reading) on the spring balance is equivalent to the force of static friction.

Frequently Asked Questions

• What are the main types of friction?
• How is static friction different from kinetic friction?
• What factors affect the magnitude of friction?
• How can friction be reduced?
• What are examples of situation where friction is beneficial
• Why is friction important in everyday life?

Conclusion

Friction is a force that assumes a fundamental part in various normal and man-made processes from the basic demonstration of strolling to the mind boggling hardware fueling our industries.Friction impacts the way of behaving and execution of items and frameworks by grasping its definition, noticing its models and perceiving the different types.We gain knowledge into how to moderate its belongings or even endeavor it for our potential benefit in planning more productive advancements and working on how we might interpret the actual world.