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Where Is Friction Not Useful:Detailed Insight And Facts

January 20, 2024December 7, 2021 by Keerthi Murthi

Friction is a force that we encounter in our everyday lives. It plays a crucial role in various aspects, from walking to driving a car. However, there are certain situations where friction is not useful and can even be a hindrance. In this article, we will explore these scenarios and understand why friction may not always be beneficial. We will delve into areas such as lubrication, transportation, and technology to uncover where friction can pose challenges and limitations. So, let’s dive in and discover where friction falls short in its usefulness.

Key Takeaways

Friction is not useful in situations where smooth and efficient movement is required, such as in the design of machinery and vehicles.
Friction can hinder the performance of moving parts and cause wear and tear, leading to decreased efficiency and increased maintenance.
In certain sports and activities, minimizing friction can enhance performance and reduce the risk of injury.
Lubricants and other methods can be used to reduce friction and improve the overall efficiency of mechanical systems.

Where is Friction Not Useful?

Friction is a force that resists the relative motion or tendency of motion between two objects in contact. While friction plays a crucial role in many aspects of our daily lives, there are certain situations where it is not useful or even detrimental. Let’s explore some of these scenarios.

In Sports

In the world of sports, friction can sometimes hinder performance. For example, in track and field events such as sprinting, athletes strive to minimize friction between their shoes and the ground. This is why sprinters wear specialized shoes with spikes that provide better traction. By reducing friction, sprinters can maximize their speed and efficiency, allowing them to achieve faster times.

For Skateboarders

Skateboarding is another area where friction can be a hindrance. Skateboarders often perform tricks and maneuvers that require smooth and controlled movements. Excessive friction between the skateboard wheels and the ground can impede these movements, making it difficult to execute tricks with precision. To overcome this, skateboarders often apply wax or other lubricants to reduce friction and ensure smoother rides.

In Airplanes

Friction also poses challenges in the aviation industry. When an airplane is in flight, it encounters air resistance, which is a form of friction. This resistance opposes the motion of the aircraft and requires additional energy to overcome. To minimize this drag, airplanes are designed with streamlined shapes and smooth surfaces. By reducing friction with the air, airplanes can achieve greater fuel efficiency and higher speeds.

Where There is No Friction

In certain situations, having no friction can be advantageous. For example, in manufacturing processes that involve moving heavy objects, friction can make it difficult to slide or transport them. By utilizing frictionless materials or lubricants, the objects can be moved with ease, reducing the effort required and increasing efficiency.

Where Friction is Not Helpful

Friction can also be a disadvantage in certain mechanical systems. For instance, in engines and machines, friction between moving parts can lead to wear and tear, reducing their lifespan and efficiency. To mitigate this, engineers employ various techniques such as using lubricants, bearings, and precision engineering to minimize friction and ensure smooth operation.

In Swimming

When it comes to swimming, friction can slow down swimmers and impede their progress through the water. Competitive swimmers wear specialized swimsuits that are designed to reduce drag and minimize friction with the water. These swimsuits are made from materials that repel water and have a smooth surface, allowing swimmers to glide through the water with minimal resistance.

In Everyday Life

Friction can sometimes be a nuisance in our everyday lives. For example, squeaky doors and hinges are often a result of friction between the moving parts. To address this, lubricants such as oil or grease are applied to reduce friction and eliminate the annoying noise. Similarly, when sliding furniture across the floor, friction can make it challenging to move them smoothly. Using furniture sliders or applying a lubricant can help reduce friction and make the process easier.

Where Friction is Used in Everyday Life

While friction can be problematic in certain situations, it is also essential in various aspects of our daily lives. For instance, the soles of our shoes have a tread pattern that increases friction with the ground, providing us with traction and preventing slips and falls. Additionally, the brakes in vehicles rely on friction to slow down and stop the moving wheels, ensuring our safety on the roads.

In conclusion, while friction is a fundamental force that has numerous benefits, there are specific scenarios where it is not useful or even detrimental. Whether it’s in sports, aviation, or everyday life, understanding when and where friction can be a disadvantage allows us to find innovative solutions to overcome its limitations and improve our efficiency and performance.

Interesting Facts about Friction

Friction is a force that we encounter in our daily lives, often without even realizing it. It plays a crucial role in various aspects of our lives, from walking to driving a car. Let’s explore some intriguing facts related to friction.

Friction is Everywhere

Friction is present in almost every interaction between objects. Whether it’s the grip between your shoes and the ground, the movement of gears in a machine, or the rubbing of your hands together, friction is at work. It is a force that opposes motion and is caused by the roughness of surfaces.

Friction Can Be Both Helpful and Harmful

While friction is essential for many everyday activities, there are instances where it can be a disadvantage. For example, in machines and engines, friction between moving parts can cause wear and tear, leading to decreased efficiency and increased energy consumption. To overcome this, engineers strive to reduce friction by using lubricants and designing smoother surfaces.

Friction Generates Heat

When two surfaces rub against each other, the friction between them generates heat. This phenomenon can be observed when you rub your hands together vigorously and feel them getting warmer. In some cases, excessive heat due to friction can cause damage or even start a fire. That’s why it’s important to be cautious and avoid situations where friction can lead to overheating.

Friction Can Be Reduced

In certain situations, reducing friction is desirable. For example, in sports, athletes often wear special shoes with low friction soles to minimize resistance and improve performance. Similarly, in industries, engineers design machines and equipment with friction-reducing mechanisms to increase efficiency and reduce energy consumption.

Friction Can Be Overcome

In some cases, friction can be a significant obstacle that needs to be overcome. For instance, when launching a rocket into space, the force of friction between the rocket and the Earth’s atmosphere can hinder its ascent. To overcome this, rockets are designed with powerful engines that generate enough thrust to propel them through the atmosphere and into space.

Friction Affects Motion

Friction has a direct impact on the motion of objects. It can either slow down or stop the motion of an object or help to maintain its speed and direction. For example, the friction between the tires of a car and the road allows the driver to control the vehicle’s movement by applying the brakes or accelerating.

Friction Can Cause Wear and Tear

One of the disadvantages of friction is that it can cause wear and tear on surfaces. When two objects rub against each other, the friction between them can lead to the erosion of materials, resulting in the need for repairs or replacements. This is why regular maintenance and lubrication are essential to minimize the effects of friction in machines and equipment.

Friction is Essential for Walking

Friction plays a vital role in our ability to walk. When we take a step, the friction between our shoes and the ground provides the necessary grip to propel us forward. Without friction, walking would be challenging, and we would constantly slip and fall.

Friction Can Create Sound

Friction can also produce sound. When you rub your hands together, the friction between your palms generates a sound. Similarly, when you play a musical instrument, the friction between the instrument’s strings and your fingers creates vibrations that produce sound waves.

Friction is Essential for Writing

The friction between the tip of a pen or pencil and the paper is what allows us to write. As we move the writing instrument across the paper, the friction between the two surfaces creates enough resistance for the ink or graphite to leave a mark.

In conclusion, friction is a force that is present in various aspects of our lives. While it can be both helpful and harmful, understanding how friction works allows us to harness its benefits and overcome its disadvantages. From walking to writing, friction plays a crucial role in our daily activities, making it an essential force to be aware of.
Conclusion

In conclusion, friction is a fundamental force that plays a crucial role in our everyday lives. It helps us walk, drive, and perform various tasks. However, there are certain situations where friction is not useful. These include instances where we want to reduce energy loss, such as in the case of mechanical systems or transportation. Friction can also be detrimental in situations where we want to minimize wear and tear, such as in the case of machinery or moving parts. Additionally, friction can hinder the efficiency of certain processes, such as in the case of fluid flow or electrical conductivity. By understanding where friction is not useful, we can find ways to mitigate its effects and improve overall performance in various fields.

Where is friction not useful and what are some techniques to reduce friction effectively?

Friction can be both beneficial and detrimental depending on the context. While friction is essential for many everyday activities like walking or driving, it can hinder performance in certain situations. One example is in the field of engineering where friction between moving parts can lead to wear and energy loss. To address this issue, techniques to reduce friction effectively have been developed. These techniques range from lubrication and surface treatments to the use of low-friction materials. To learn more about these techniques, visit “Techniques to Reduce Friction Effectively”.

Frequently Asked Questions

When is friction not useful in sports?

Friction is not useful in sports when athletes want to achieve high speeds, such as in track and field events like sprinting or when a ball needs to travel a long distance, like in golf or baseball.

Where is friction not a good thing for a skateboarder?

Friction is not a good thing for a skateboarder when they are attempting tricks that require smooth and controlled movements, such as slides or grinds. Friction can hinder their ability to execute these tricks properly.

Why is air resistance friction not useful for an airplane?

Air resistance, which is a form of friction, is not useful for an airplane because it creates drag, which can slow down the aircraft and increase fuel consumption. To maximize efficiency, airplanes are designed to minimize air resistance.

Where is there no friction?

In a frictionless environment or on frictionless surfaces, there is no friction. These conditions can be simulated in laboratories or achieved in certain applications to study the effects of friction or reduce its impact.

Where is friction not helpful?

Friction is not helpful in situations where smooth and effortless movement is desired, such as in the design of machinery or vehicles. Excessive friction can cause wear and tear, reduce efficiency, and lead to energy losses.

Why is friction not useful in swimming?

Friction is not useful in swimming because it creates resistance against the movement of the swimmer through the water. To swim faster, swimmers try to minimize friction by wearing streamlined swimsuits and using efficient swimming techniques.

When is friction not useful in everyday life?

Friction is not useful in everyday life when it causes unwanted wear and tear, hinders movement, or reduces efficiency. For example, friction between the moving parts of a machine can lead to breakdowns or friction between shoes and the floor can make walking difficult.

Where is friction used in everyday life?

Friction is used in everyday life in various applications, such as when walking, driving a car, or using tools. It helps us maintain grip, control motion, and perform tasks that require force or traction.

What are some sports where friction is not useful?

Sports where friction is not useful include ice hockey, speed skating, and skiing. In these sports, reducing friction allows athletes to glide smoothly and achieve higher speeds.

How is friction not useful when ice skating?

Friction is not useful when ice skating because it can slow down the skater and make it difficult to perform certain maneuvers. Skaters often try to minimize friction by using smooth ice surfaces and wearing appropriate skating gear.

Why is friction not always useful?

Friction is not always useful because it can cause energy losses, wear and tear, and hinder movement. In certain situations, reducing or eliminating friction can lead to improved efficiency, performance, and longevity.

Can you provide two examples where friction is not useful?

Two examples where friction is not useful are in the design of high-speed trains and the development of low-friction bearings. In both cases, reducing friction allows for faster and more efficient transportation and machinery.

Is friction not useful in skiing?

Friction is not useful in skiing when skiers want to achieve high speeds or perform tricks. By reducing friction, skiers can glide smoothly on the snow and have better control over their movements.

Where is friction useful?

Friction is useful in various applications, such as walking, driving, and gripping objects. It helps us maintain stability, control motion, and perform tasks that require traction or force.

Also Read:

Find Coefficient Of Friction Given Velocity And Distance: Detailed Analysis and Problems

January 21, 2024December 4, 2021 by Keerthi Murthi

To find the coefficient of friction, the normal reaction and the friction involved in the necessary quantities. But how to find coefficient friction given velocity and distance?

The velocity and the distance contribute to the friction evolving between the surfaces. The impact of these two quantities can be resolved. By knowing the velocity and the distance moved by the object, the coefficient of friction can be calculated.

How to find coefficient of friction given velocity and distance moved by the object

To find the coefficient of friction given velocity and distance, let us consider an object of mass ‘m’ moving with a velocity ‘v’ at a distance ‘d’ from the initial position. The friction force F_f is retards the motion of the object in the direction opposite to the movement. The normal reaction F_n is acting perpendicular to the motion of the object. The motion of the object is influenced by the gravity ’g’, which results in a normal reaction.

We can find the coefficient friction given velocity and distance by two methods. Let us it discuss one by one.

Method 1: considering the work done by the friction

The work done by the friction on the object is given by

W = PE+ KE+ E_loss

Since the object is moving, the stored potential energy is zero, and the energy loss is negligible during the process. So the work done can be rewritten as

Where m is the mass of the object and v is the velocity at which the object is moving.

This work done is equal to the friction force times the distance, so we can write the equation as

The friction force acting on the object is given by

F_f= µF_n

Where µ is the coefficient of friction and F_nis the normal reaction.

The normal reaction is equal to the net weight of the object given by F_n=mg

So that the friction is given by the equation,

F_f= µmg …..(2)

Since the above two equations of friction are the same, we can equate them

Rearranging the equation we get,

Now consider that initially the object is moving with velocity v₀, with the time its velocity changes and finally it is moving with velocity v_f covering the distance d, then the coefficient of friction is given by

Method 2: By using the Kinematics

The kinematic equation of motion for given velocity and distance is,

v_f² = v₀² + 2ad

Where, v_f² is the final velocity of the moving object.

v₀² is the initial velocity of the moving object.

a is the acceleration, and d is the distance travelled by the object.

Here we consider the object is moving with a constant velocity so that the final velocity vf2 become zero. Hence we can modify the equation as

0 = v₀² + 2ad

-v₀² = 2ad

From Newton’s second law of motion, the relation between the acceleration and the force is given by,

F = m*a

Substituting in the above equation, we get

The force acting on the object cannot have a negative value. We can take the magnitude of the equation as,

Since in this case, we have considered the force acting on the object is friction force so that substituting the formula of the friction, we get the equation as

Generally, we can write the equation as

On rearranging the terms, we get the coefficient of friction as,

It is clear that the coefficient of friction arrived from both methods are the same. Using the above formula, we can find the coefficient of friction given velocity and distance.

Solved Problems On Coefficient Of Friction

An object of mass of 2kg is moving with a velocity of 12ms^-2, the friction force acting on the body make the object stop at a distance of 22m. Find the coefficient of friction and hence calculate the friction force. The acceleration due to gravity g given as 10ms^-2.

Solution:

Given: Mass of the object m = 2kg

Velocity v = 13ms^-2

Distance covered by the object d = 22m

Acceleration due to gravity g = 10ms^-2

The formula to find coefficient of friction given velocity and distance is

Substituting the values of the given terms in the above equation

µ = 0.38

The formula to calculate friction is

F_f = µmg

F_f = 0.38×10×2

F_f = 7.68N.

Find the coefficient of friction given velocity and distance as 28ms^-2 and 34m respectively and hence find the normal reaction and the friction force. (Given: Mass of the object is 4kg and Acceleration due to gravity is 10 ms^-2).

Solution:

The velocity is 17ms^-2

The distance travelled by the object is34m.

The coefficient of friction for given velocity and distance is given by the formula

Substituting the values in the expression,

µ = 0.425

The normal reaction is given by F_N = m*g

F_N = 4 × 10

F_N = 40 N.

The friction force acting on the object is F_f = µ F_N

F_f = 0.425 × 40

F_f = 17 N.

A body of mass of 12kg is moving on a rough surface. It travelled a distance of 72m, and then its motion is hindered by the friction force of 45N. Calculate the coefficient of friction and hence find the velocity at which the body is moving.

Solution:

Mass of the body m = 12kg

The distance traveled by the body d = 72m

The friction force acting on the body F_f= 45N

Acceleration due to gravity g = 9.8 ms^-2.

The coefficient of friction for given friction is given by the formula

Substituting values in the above equation

µ = 0.382

To find the velocity, let us consider the equation

On rearranging the terms, we get the equation for the velocity as,

v² = 2µgd

Substituting the values

v² = 2× 0.382× 9.8× 72

v² = 539.07

Taking the square root, we get

The velocity at which the body is moving is v = 23.21 ms^-2.

The coefficient of friction is 0.46, and the mass of the object is 7kg. The object is moving with a constant velocity of 46 ms^-2. Calculate the distance travelled by the object after friction retards the object’s motion.

Solution:

The coefficient of friction µ = 0.46

Mass of the object m = 7kg

Velocity of the object v = 16 ms^-2

Acceleration due to gravity g = 9.8 ms^-2

Rearranging the expression

d = 28.39m.

The object covers a distance of 28.39m before it stops its motion.

A block of mass 5kg is moving with the initial velocity of 12ms^-2. After a time t, its velocity is increased by 19ms^-2 and covers a distance of 33m, then its motion is stopped by the friction. Find the coefficient of friction given velocity and distance and hence find the friction required to stop the motion of the object.

Solution:

The initial velocity of the object v₀ = 12 ms^-2

The final velocity of the object v_f = 19ms^-2

The distance covered by the object d = 33m

Mass of the object m = 5kg

The coefficient of friction for given initial and final velocity is given by the expression

µ = 0.33

The friction required to stop the motion of the object is

F_f = µmg

F_f = 0.33× 5× 9.8

F_f = 16.17 N.

Also Read:

How To Find Coefficient Of Kinetic Friction (Updated 2023)

January 21, 2024November 30, 2021 by Keerthi Murthi

A dimensionless physical quantity the specifies the interaction of two object is called coefficients.

The value coefficient of kinetic friction is changes depending on the nature of the material used. Generally, the coefficients give the ratio of two quantities involved in the action. In this post, let us discuss how to find coefficient kinetic friction and its consequences.

How to find coefficient of kinetic friction

Let us consider two surfaces, such that one surface is moving in contact with another one. The friction always resists the movement and finally stops the motion of the surface in the opposite direction of the motion.

A general formula to find the coefficient friction is given by the ratio of friction force and the normal reaction acting on the surfaces in a perpendicular direction.

Image credits: Image by Pexels from Pixabay

how to find coefficient of kinetic friction — **Free body diagram of Kinetic Frictional Force**

On rearranging the above expression, we can find out the kinetic friction as well.

How to calculate uncertainty of coefficient of kinetic friction

The uncertainty occurs due to the misalignment of the coordinate axes along the direction of the motion. Along with the normal force, the tangential force is acting on the system. This tangential force gives an account for the occurrence of uncertainty of the coefficient of the kinetic friction.

The value of the coefficient is not measured directly through the experiment. It is determined by calculating all the forces acting on the system and the angle of inclination of the object with the surface.

The general expression for the coefficient of kinetic friction is given by

Let us consider the sliding of an object in a plane. The sliding of the object is taken for the various angle of the object along the plane for different instances. Then calculate the coefficient of kinetic friction for all the angles.

The above statement tells that the value of coefficient of kinetic friction changes with change in the angle. This deviation is due to the uncertainty of kinetic friction coefficient. Let us study how to find the coefficient of kinetic friction with uncertainty.

Along with the normal force F_N, the tangential force also contributes to the evolution of friction force. This leads to an error in calculating the coefficient of kinetic friction. The uncertainty measurement compensates for the error that occurred during the calculation.

The normal force is acting along the Y-axis, and the angle of misalignment be β. And the tangential force is acting along the X-axis with the misaligned angle of α. These normal and tangential forces are in contact, and the resultant force along the X and Y axes are given by

F_X = F_F cosα + F_N sinα

F_X = µ_K F_N cosα + F_N sinα

F_X= F_N (µ_K cosα + sinα)

Similarly for Y axis

F_Y = F_N cosβ – F_F sin β

F_Y = F_N (cosβ – µ_K sinβ) By solving the resultant forces, the uncertainty in the friction is given as

In order to calculate the combined standard uncertainty measurement, the standard uncertainty function must be a standard value of input values and the partial derivatives of the frictional coefficient. The law of “propagation of uncertainty” helps us to give a standard value for the uncertainty in the friction. It is given by the equation.

Where, u is the uncertainty of the given system.

On differentiating the individual variables, we get the standard value of uncertainty in the coefficient of kinetic friction.

This gives the standard uncertainty value for the input forces acting on the system. By substituting these values in the partial derivative equation, we get the uncertainty value.

How to calculate coefficient of kinetic friction without mass

To calculate the coefficient of kinetic friction without mass, let us consider a block moving on a flat surface. The block of mass “m” moving with acceleration “a” in the direction of the applied force. The normal force acting between the block and the surface be F_Nwhich is perpendicular to the motion of the block. We know that the friction force acting between the block and surface to retard the motion is given by the equation,

F_K = µ_K F_N

According to Newton’s second law of motion, the force acting on the moving body equals mass times the acceleration.

F = m* a

The normal force is influenced by the force of gravity given as

F_N= m*g

Substituting in the equation of frictional force, we get

F_K = µ_K m*g

Since the body is moving and the force acting on the block is kinetic friction force, Newton’s law can be modified as

F_K = m* a

On equating the above two equations we get,

µ_K m*g = m* a

µ_K g = a Rearranging the equation we get,

This gives the value of the coefficient of kinetic friction.

Determining the Coefficient of Kinetic Friction on an Inclined Plane

Kinetic Friction on an Inclined Plane

Forces Acting on the Object:

Gravitational force: $F_{gravity} = m cdot g$
Normal force: $F_{normal}$
Frictional force: $F_{friction}$

Decomposing the Gravitational Force: The gravitational force can be split into two components:

Parallel to the incline: $F_{gparallel} = m cdot g cdot sin(theta)$
Perpendicular to the incline: $F_{gperp} = m cdot g cdot cos(theta)$

Frictional Force: When an object moves at a constant velocity on the incline:

Since $F_{normal} = F_{gperp}$ , and $F_{friction} = F_{gparallel}$ , we get: $mu_k = tan(theta)$

Example:

Suppose you have a block on a 30° incline, and you notice it starts to slide at a constant velocity without any external push. Determine the coefficient of kinetic friction.

Given: $theta = 30^circ$

To find: $mu_k$

Using the formula: $mu_k = tan(theta)$

Plugging in the given value: $mu_k = tan(30^circ)$ $mu_k approx 0.577$

Thus, the coefficient of kinetic friction between the block and the incline is approximately 0.577.

How to Find the Coefficient of Kinetic Friction with Acceleration

Kinetic Friction with Acceleration

When an object slides over a surface, it experiences a resistive force due to the surface. This resistive force is called kinetic friction. The magnitude of the kinetic frictional force ( $F k $ ) is given by:

$F_{k} = mu_{k} times N$

Where:

$mu_{k}$ is the coefficient of kinetic friction.
$N$ is the normal force (or the force acting perpendicular to the surface). In many cases, this is equal to the weight of the object if the surface is horizontal.

If an object is moving on a horizontal surface and no other horizontal forces are acting on it, then the net force ( $F_{net}$ ) acting on the object due to friction is:

$F_{net} = F_{k}$

Using Newton’s second law ( $F_{net} = m times a$ ), where $m$ is the mass of the object and $a$ is its acceleration, we can equate the above equations to find:

$m times a = mu_{k} times N$

To solve for $mu_{k}$ , you can rearrange this equation:

$mu_{k} = frac{m times a}{N}$

Example:

Suppose we have a block of mass 10 kg sliding on a horizontal surface. The block has an acceleration of 2 m/s² in the direction of motion. Given that the gravitational acceleration ( $g$ ) is approximately 9.81 m/s², we want to find $mu_{k}$ .

First, calculate the normal force ( $N$ ):

$N = m times g$ $N = 10 text{ kg} times 9.81 text{ m/s}^2 = 98.1 text{ N}$

Then, use the formula for $mu_{k}$ :

$mu_{k} = frac{m times a}{N}$ $mu_{k} = frac{10 text{ kg} times 2 text{ m/s}^2}{98.1 text{ N}}$ $mu_{k} approx 0.204$

So, the coefficient of kinetic friction between the block and the surface is approximately 0.204.

How to Find the Coefficient of Kinetic Friction Without Friction Force

kinetic friction without friction force

In real-world scenarios, you may not always have a direct measure of the frictional force between two surfaces, but there might still be a need to determine the coefficient of kinetic friction ( $μ k $ ). One way to derive $μ k $ is by analyzing the motion of an object on an incline.

When an object is sliding down an incline without acceleration (i.e., at constant velocity), the net force acting on it is zero. This means that the component of gravity pulling it down the incline is balanced by the frictional force resisting its motion.

Let’s dive into the mathematics of this:

Gravitational Force Parallel to the Incline

The component of gravitational force acting parallel to the incline can be found using:

$F_{parallel} = mg sin(theta)$

Where:

$m$ is the mass of the object.
$g$ is the acceleration due to gravity (approximately $9.81 , text{m/s}^2$ near the Earth’s surface).
$theta$ is the angle of inclination.

Frictional Force

The frictional force acting on the object can be represented as:

$F_{friction} = mu_k N$

Where $N$ is the normal (perpendicular) force. For an incline, the normal force is given by:

$N = mg cos(theta)$

Thus, the frictional force is:

$F_{friction} = mu_k mg cos(theta)$

Balancing the Forces

At constant velocity:

$F_{parallel} = F_{friction}$

Substituting in our expressions:

$mg sin(theta) = mu_k mg cos(theta)$

From this, we can solve for $mu_k$ :

$mu_k = tan(theta)$

Worked-out Example

Let’s say an object is observed to slide down an incline at a constant velocity, and the angle of the incline, $theta$ , is measured to be 30°.

Using the derived formula:

$mu_k = tan(30^{circ})$

$mu_k approx 0.577$ (rounded to three decimal places)

Thus, the coefficient of kinetic friction, $mu_k$ , between the object and the incline is approximately 0.577.

NOTE: this method assumes no other forces (like air resistance) are acting on the object, and that the object moves at a constant velocity down the incline.

How to Find the Coefficient of Kinetic Friction Using Velocity and Distance

In many experimental or real-world scenarios, you might have information about the initial velocity of an object and the distance it traveled before coming to a stop due to friction. This data can be invaluable in determining the coefficient of kinetic friction ( $μ k $ ) between the object and the surface it’s sliding upon.

kinetic friction with velocity and distance

Let’s understand the principles behind this:

Work Done by Frictional Force

The work done by the frictional force over the distance ( $d$ ) is equal to the change in kinetic energy of the object.

$W_{friction} = mu_k N d$

Where:

$N$ is the normal (perpendicular) force. On a horizontal surface, $N = mg$ , where $m$ is the mass of the object and $g$ is the acceleration due to gravity (approximately $9.81 , text{m/s}^2$ ).

Change in Kinetic Energy

The object’s initial kinetic energy (when it has velocity $v$ ) is:

$KE_{initial} = frac{1}{2} mv^2$

Since the object comes to a stop, its final kinetic energy is zero. Thus, the change in kinetic energy is:

$Delta KE = frac{1}{2} mv^2$

Equating Work and Change in Kinetic Energy

For the object to come to a stop:

$W_{friction} = Delta KE$

Substituting in our expressions:

$mu_k mgd = frac{1}{2} mv^2$

From this equation, we can solve for $mu_k$ :

$mu_k = frac{v^2}{2gd}$

Worked-out Example

Imagine an object sliding on a horizontal surface. It has an initial velocity of $5 , text{m/s}$ and comes to a stop after traveling $10 , text{m}$ . Let’s determine the coefficient of kinetic friction, $mu_k$ , between the object and the surface.

Using the derived formula:

$mu_k = frac{5^2}{2(9.81)(10)}$

$mu_k approx frac{25}{196.2}$

$mu_k approx 0.127$ (rounded to three decimal places)

Thus, the coefficient of kinetic friction, $mu_k$ , between the object and the surface is approximately 0.127.

NOTE: This method is based on the principle of conservation of energy. It assumes that the only force doing work on the object (leading to a change in its kinetic energy) is the frictional force, with no other forces (like air resistance) at play.

How to Find the Coefficient of Kinetic Friction Using Mass and Force

When an object is in motion on a horizontal surface and you know the force being applied to it and its mass, you can determine the coefficient of kinetic friction ( $μ k $ ) between the object and the surface. Let’s delve into the process step by step.

Frictional Force

The frictional force acting against the motion of an object on a horizontal surface can be given by:

$F_{friction} = mu_k N$

Where:

$N$ is the normal (perpendicular) force. On a horizontal surface, $N = mg$ , where $m$ is the mass of the object and $g$ is the acceleration due to gravity (approximately $9.81 , text{m/s}^2$ ).

Net Force Acting on the Object

If a force ( $F$ ) is being applied to the object to keep it moving at a constant velocity on the horizontal surface, the net force is zero (since there’s no acceleration). This means that the applied force $F$ is balanced by the frictional force:

$F = F_{friction}$

Finding $μ k $

Using the above equations, we can express $F$ in terms of $μ_{k}$ :

$F = mu_k mg$

From this equation, we can solve for $mu_k$ :

$mu_k = frac{F}{mg}$

Worked-out Example

Let’s consider an object with a mass of $10 , text{kg}$ being pushed on a horizontal surface. To keep the object moving at a constant velocity, a force of $20 , text{N}$ is applied. Determine the coefficient of kinetic friction, $mu_k$ , between the object and the surface.

Using the derived formula:

$mu_k = frac{20}{10(9.81)}$

$mu_k approx frac{20}{98.1}$

$mu_k approx 0.204$ (rounded to three decimal places)

Thus, the coefficient of kinetic friction, $mu_k$ , between the object and the surface is approximately 0.204.

NOTE: This approach assumes that the object is moving at a constant velocity, which means there’s no acceleration and the net force acting on it is zero. This is crucial because it lets us equate the applied force with the frictional force.

Frequently Asked Questions

Does the calculation of kinetic friction without mass give the same value of coefficient obtained by considering the mass?

Yes, the value of the coefficient of kinetic friction with or without considering the mass is the same.

Since friction is a quantity that is independent of the absolute mass of the system, the mass does not affect the value of the friction involved in the process. Hence the coefficient of kinetic friction remains unchanged with or without considering the mass of the object.

Does the nature of the material influence the coefficient of kinetic friction?

The coefficient of kinetic friction is a numerical value that gives the evidence for the presence of friction force between the objects.

Since friction is influenced by the nature of the material, it is so evident that its coefficient is also largely influenced by the nature of the material.

What is necessary to find the coefficient of kinetic friction of a moving object?

Without the coefficient of kinetic friction, it is quite difficult to measure the force that makes the object to hinders its motion.

The friction is always proportional to the normal perpendicular reaction between the surfaces. This proportionality relation is specified by the dimensionless quantity called the coefficient. The coefficient of kinetic friction measures the absolute value of the friction force that stops the moving object.

Can the value of the coefficient of kinetic friction be greater than 1?

Generally, the value of the kinetic friction coefficient ranges from 0 to 1. Sometimes it gives a value of coefficient exceeds 1.

If the influence of friction force is stronger than the perpendicular reaction between the two moving surfaces, the value of kinetic friction coefficient exhibit the value greater than 1. Maximum frictional force makes the object to restrict its motion so that automatically the coefficient of kinetic friction increases proportionally.

Does greater coefficient of kinetic friction lead to energy dissipation?

The dissipation of energy due to friction can be described in terms of energy conservation Law.

A greater coefficient of kinetic friction means the friction force is stronger than the applied force. The challenging task is to keep the body in motion in the presence of friction. Hence it takes much force to keep the body in motion. The maximum force exerted to keep the body in motion causes the kinetic energy dissipation released in the form of heat.

What is the coefficient of friction?

A: The coefficient of friction is a dimensionless quantity that represents the ratio of the force of friction between two objects to the force pressing them together.

How can I calculate the coefficient of friction?

A: The coefficient of friction can be calculated by dividing the force of friction by the normal force acting on the object.

What is the difference between kinetic and static friction?

A: Kinetic friction occurs when two objects are in relative motion, while static friction occurs when there is no relative motion between the two objects, i.e., the objects are at rest.

What is the formula for the coefficient of kinetic friction?

A: The formula for the coefficient of kinetic friction is μk = Fk/N, where μk is the coefficient of kinetic friction, Fk is the force of kinetic friction, and N is the normal force.

How can I find the coefficient of kinetic friction for a moving object on a flat surface?

A: To find the coefficient of kinetic friction for a moving object on a flat surface, you can use the equation μk = tan(θ), where θ is the angle between the force of kinetic friction and the force perpendicular to the surface.

What is the equation for calculating the force of kinetic friction?

A: The equation for calculating the force of kinetic friction is Fk = μkN, where Fk is the force of kinetic friction, μk is the coefficient of kinetic friction, and N is the normal force.

How can I find the coefficient of static friction?

A: The coefficient of static friction can be found by dividing the maximum force of static friction by the normal force.

What is the relationship between the coefficients of static and kinetic friction?

A: The coefficient of static friction is generally greater than the coefficient of kinetic friction for a given pair of surfaces.

How can I solve a friction problem using the coefficient of friction?

A: To solve a friction problem using the coefficient of friction, you can set up equations based on the friction equation and other relevant equations, and solve for the unknown variables using algebraic methods.

Also Read:

Kinetic Friction vs Kinetic Force:Detailed Analysis

January 21, 2024November 29, 2021 by Keerthi Murthi

The kinetic friction and the kinetic force seem like the same quantity, but they are not the same.

Though Kinetic friction and kinetic force are both exerted on the moving objects, let us study the facts which make these two physical quantities differ by analyzing Kinetic friction vs Kinetic force in this post.

Comparison between the Kinetic Friction vs Kinetic Force

The below table may help you to understand the nature and behavior of kinetic friction vs kinetic force.

	Kinetic friction	Kinetic force
Kinetic energy	Kinetic friction reduces the kinetic energy of the system. This loss of kinetic energy results in releasing heat energy.	Since the kinetic force makes the body accelerate more, the kinetic energy increases with increased acceleration.
Nature of the surface	The Kinetic friction constantly evolved between the two solid rough surfaces. The surface must be rough. It may be flat or inclined.	The kinetic force is exerted only in the inclined plane because in an inclined plane to move upward it takes more force for the motion. Since on the flat surface, the body does not require any force to keep on moving. So that on a flat surface, the acceleration is constant.
Gravity	The influence of gravity on kinetic friction is constant as kinetic friction is independent of gravity. Still, the factor involved in the kinetic friction, i.e., the normal force, is influenced by the acceleration due to gravity.	Kinetic force is primarily influenced by gravity. The object accelerates rapidly down the ramp because the gravitational pull-down ramp is more.
Net weight	The net weight of the object gives the normal force acting on the body, which is responsible for the kinetic friction.	The kinetic force is itself considered as a portion of the possible net weight of the object.
Coefficients	The ratio of kinetic friction and the perpendicular reaction gives the coefficient of kinetic friction. This is a dimensionless quantity which exerts wide influence over the kinetic friction.	The coefficient kinetic force is the wrong terminology to explain the force. Since all the coefficients are dimensionless, quantity is used to express the nature of the physical quantity. But in the case of kinetic friction, it is an irrelevant quantity.
Direction	Kinetic friction always acts in the opposite direction to the relative motion of the objects.	Kinetic force acting on the moving body is in the direction of the relative motion of the body.

The study of kinetic friction vs kinetic force convinces us how the two forces exerted on the moving body differ from one another.

Definition of kinetic friction and kinetic force

In order to understand the action of kinetic friction vs kinetic force on the object, the definition of them is very helpful.

Kinetic friction is the resistance offered to the moving body to restrict its motion. In contrast, the Kinetic force is probably a net force that is exerted on the object parallel to the plane of inclination that causes the object to accelerate.

By the above definition, it is clear that the kinetic friction stops the moving object and the kinetic friction allows the moving object to accelerate more.

Interesting facts to remember

When the body moves down the hill, the kinetic force is maximum, moving rapidly. As it moves near the flat surface, the kinetic force becomes minimum, and in some instances, its motion is retarded by the kinetic friction.
Both kinetic friction and kinetic force are applied to the types of forces exerted on the body; these are equal and opposite to each other.
It is impossible to stand up if the friction acting between our body and the surface is absent.
Wheels are used to reduce friction and accelerate rapidly, but the wheel couldn’t work properly without friction.
In the case of both kinetic friction and kinetic force, the energy may get lost by releasing some amount of heat.
The kinetic friction always retards the kinetic force.
In some sense, kinetic force is an uncommon usage term. Kinetic force is considered as the impulsive force which arises due to collision. It is referred to as the contact force and given by Newton’s laws of motion as, Impulse = Ft
Kinetic friction is the one responsible for the object’s motion, while kinetic force increases the speed of the movement.

Frequently asked questions

Does the kinetic friction remain constant throughout the motion?

When the applied force is maximum, and overcomes the stiction, then the kinetic friction evolves.

The kinetic friction remains constant until the body gains the energy to move when the kinetic energy is lost in the form of heat and reaches the threshold motion, the kinetic friction increases.

Does the increase in speed increase the kinetic friction?

No, the increase or decrease in the speed does not alter the kinetic friction at the moderate level.

The kinetic friction always increases when the normal force between the objects increases. When the speed is increased slightly, the kinetic friction remains constant. If the speed is increased to the greater value, the friction offered by the surface becomes negligible.

How does the kinetic energy increase with the kinetic force?

Kinetic force makes the object accelerate more; this helps the energy to exert more on the body.

When the speed of the body increases, the body requires more energy to keep the force steady, the distance traveled by the body increases at a constant force as the force keeps on increasing the kinetic energy increases too.

What is the major application of kinetic friction?

The kinetic friction is mainly applicable in lubrication.

The wear and tear of the machinery depends on the kinetic friction. The car brakes use the principle of kinetic friction, which indeed uses lubrication.

How does kinetic friction be responsible for the motion?

The kinetic friction converts the kinetic energy into heat energy.

When the two surfaces are in contact, and when the force is applied to one surface, it begins to move. The kinetic energy is converted into heat only when the surface of one block slides over another surface. This energy is sufficient to cause motion.

Does the mechanical energy is conserved in the kinetic friction?

Since the kinetic friction reduces the mechanical energy of the system, it is considered non-conservative.

If the total sum of potential energy and the kinetic energy is constant then the energy is said to conserved. In the case of kinetic friction, the energy conversion between the potential and the kinetic energy does not occur. Hence the mechanical energy is not conserved.

How does the kinetic energy equal to the kinetic friction?

The kinetic friction and kinetic energy are not related to one another. Both are different components.

Kinetic energy is the energy correlated to the body in motion. This energy may get reduced if the friction exerted on the body is more. But kinetic energy and the kinetic friction are unequal quantities.

Also Read:

How To Calculate Kinetic Friction:Exhaustive Insights

January 21, 2024November 24, 2021 by Keerthi Murthi

Friction is a force that opposes the motion of an object when it comes into contact with another surface. It plays a crucial role in our daily lives, affecting the way objects move and interact with each other. Kinetic friction, specifically, refers to the frictional force between two surfaces when they are in relative motion. In this blog post, we will explore how to calculate kinetic friction, including identifying the necessary variables, step-by-step calculation process, and worked-out examples. We will also discuss special cases in calculating kinetic friction and how to determine the coefficient of kinetic friction.

How to Calculate Kinetic Friction

Identifying the Necessary Variables

Before diving into the calculation of kinetic friction, it’s essential to identify the variables involved. These variables include:

Coefficient of kinetic friction $\(\mu_k$ ): This value represents the interaction between the surfaces in contact and determines the amount of friction present.
Normal force (N): The force exerted by a surface perpendicular to the object in contact. It is equal to the weight of the object if no other vertical forces are acting on it.
Applied force (F): The force applied to the object in the direction of motion.

Step-by-Step Process of Calculating Kinetic Friction

To calculate the kinetic friction force $\(f_k$ ), we can use the following formula:

$f_k = \mu_k \cdot N$

The steps to calculate kinetic friction are as follows:

Determine the coefficient of kinetic friction $\(\mu_k$ ) between the two surfaces in contact.
Calculate the normal force (N) exerted on the object.
Multiply the coefficient of kinetic friction $\(\mu_k$ ) by the normal force $N) to obtain the kinetic friction force (\(f_k$ ).

Worked Out Example: Calculating Kinetic Friction

Let’s work through an example to better understand how to calculate kinetic friction. Consider an object with a mass of 10 kg resting on a horizontal surface. The coefficient of kinetic friction between the object and the surface is 0.5. If a force of 20 N is applied horizontally to the object, what is the magnitude of the kinetic friction force?

Determine the normal force N: Since the object is on a horizontal surface and no other vertical forces are acting, the normal force is equal to the weight of the object, which is $\(N = mg = 10 \, \text{kg} \times 9.8 \, \text{m/s}^2 = 98 \, \text{N}$ .
Calculate the kinetic friction force $\(f_k$ ): Using the formula $f_k = \mu_k \cdot N$ , we have $f_k = 0.5 \times 98 \, \text{N} = 49 \, \text{N}$ .

Therefore, the magnitude of the kinetic friction force is 49 N.

Special Cases in Calculating Kinetic Friction

Calculating Kinetic Friction on an Incline or Slope

When dealing with a surface inclined at an angle, the calculation of kinetic friction becomes slightly more complex. In addition to the variables mentioned earlier, we need to consider the angle of the incline $\(\theta$ ). The formula to calculate the kinetic friction force on an incline is as follows:

$f_k = \mu_k \cdot N \cdot \cos(\theta)$

Here, the normal force N is equal to $\(mg \cdot \cos(\theta)$ , where $m$ is the mass of the object and $g$ is the acceleration due to gravity.

Calculating Kinetic Friction without Coefficient

In some cases, the coefficient of kinetic friction may not be provided. However, it is still possible to calculate the kinetic friction force using other known variables. One approach is to use the equation of motion:

$f_k = m \cdot a$

Where $m$ is the mass of the object and $a$ is the acceleration.

Calculating Kinetic Friction from Static Friction

If the object is initially at rest and then starts moving, we can determine the kinetic friction force using the static friction force. The static friction force $\(f_s$ ) is the force required to overcome the initial resistance to motion. Once the object starts moving, the static friction force transitions into kinetic friction. Therefore, the kinetic friction force $\(f_k$ ) is equal to the magnitude of the static friction force.

How to Determine the Coefficient of Kinetic Friction

The coefficient of kinetic friction is an essential factor in calculating kinetic friction. It provides information about the interaction between the two surfaces and determines the amount of friction present. There are different ways to determine the coefficient of kinetic friction, depending on the given variables.

Finding the Coefficient of Kinetic Friction with Mass and Force

If the mass $\(m$ ) and the applied force $\(F$ ) are known, the coefficient of kinetic friction can be determined using the formula:

$\mu_k = \frac{f_k}{N} = \frac{f_k}{mg}$

Where $f_k$ is the kinetic friction force, $N$ is the normal force, $m$ is the mass of the object, and $g$ is the acceleration due to gravity.

Finding the Coefficient of Kinetic Friction when Given Acceleration

If the acceleration $\(a$ ) of the object is known, the coefficient of kinetic friction can be determined using the equation of motion:

$f_k = m \cdot a$

Substituting the formula for the kinetic friction force $\(f_k = \mu_k \cdot N$ ), we get:

$\mu_k \cdot N = m \cdot a$

From this equation, we can solve for $\mu_k$ :

$\mu_k = \frac{m \cdot a}{N} = \frac{m \cdot a}{mg}$

Worked Out Example: Determining the Coefficient of Kinetic Friction

how to calculate kinetic friction — Image by Casint – Wikimedia Commons, Wikimedia Commons, Licensed under CC BY-SA 4.0.

Let’s work through an example to illustrate how to determine the coefficient of kinetic friction. Suppose an object with a mass of 5 kg is moving with an acceleration of 2 m/s². If the normal force is 40 N, what is the coefficient of kinetic friction?

Using the formula $\mu_k = \frac{m \cdot a}{N}$ , we can calculate:

$\mu_k = \frac{5 \, \text{kg} \times 2 \, \text{m/s}^2}{40 \, \text{N}} = 0.25$

Therefore, the coefficient of kinetic friction is 0.25.

By understanding how to calculate kinetic friction and determine the coefficient of kinetic friction, we can better analyze and predict the behavior of objects in motion.

How does kinetic friction impact the work done by friction?

The concept of kinetic friction plays a crucial role in understanding the work done by friction. When an object moves against a surface, kinetic friction opposes its motion by exerting a force. This force, along with the displacement of the object, determines the work done by friction. To delve deeper into how friction impacts work and motion, it is worth exploring the article on Friction’s impact on work and motion. The linked content provides valuable insights into the relationship between friction, work, and the resulting impact on objects in motion.

Numerical Problems on how to calculate kinetic friction

Problem 1:

A block of mass $m$ is placed on a horizontal surface. The coefficient of kinetic friction between the block and the surface is $\mu_k$ . The block is pushed with a force $F$ . Determine the magnitude of the force required to keep the block moving at a constant velocity.

Solution:

The force of kinetic friction can be calculated using the equation:

$f_k = \mu_k \cdot N$

where $f_k$ is the force of kinetic friction, $\mu_k$ is the coefficient of kinetic friction, and $N$ is the normal force.

Since the block is on a horizontal surface, the normal force is equal to the weight of the block:

$N = m \cdot g$

where $m$ is the mass of the block and $g$ is the acceleration due to gravity.

Substituting the value of $N$ in the equation for $f_k$ , we get:

$f_k = \mu_k \cdot m \cdot g$

To keep the block moving at a constant velocity, the force applied, $F$ , must be equal to the force of kinetic friction:

$F = f_k$

Therefore, the magnitude of the force required to keep the block moving at a constant velocity is:

$F = \mu_k \cdot m \cdot g$

Problem 2:

A car of mass $m$ is traveling on a horizontal road with a velocity $v$ . The coefficient of kinetic friction between the tires of the car and the road is $\mu_k$ . Determine the minimum stopping distance of the car if the brakes are applied.

Solution:

The force of kinetic friction acting on the car when the brakes are applied can be calculated using the equation:

$f_k = \mu_k \cdot N$

where $f_k$ is the force of kinetic friction, $\mu_k$ is the coefficient of kinetic friction, and $N$ is the normal force.

Since the car is on a horizontal road, the normal force is equal to the weight of the car:

$N = m \cdot g$

where $m$ is the mass of the car and $g$ is the acceleration due to gravity.

Substituting the value of $N$ in the equation for $f_k$ , we get:

$f_k = \mu_k \cdot m \cdot g$

The deceleration of the car, $a$ , can be calculated using the equation:

$a = \frac{f_k}{m}$

The minimum stopping distance of the car, $d$ , can be calculated using the equation:

$d = \frac{v^2}{2a}$

Substituting the value of $a$ in the equation for $d$ , we get:

$d = \frac{v^2}{2 \cdot \frac{f_k}{m}}$

Simplifying the equation, we have:

$d = \frac{v^2 \cdot m}{2 \cdot f_k}$

Therefore, the minimum stopping distance of the car is:

$d = \frac{v^2 \cdot m}{2 \cdot \mu_k \cdot m \cdot g}$

Problem 3:

A block of mass $m$ is placed on an inclined plane with an angle of inclination $\theta$ . The coefficient of kinetic friction between the block and the inclined plane is $\mu_k$ . Determine the acceleration of the block as it slides down the inclined plane.

Solution:

The force of gravity acting on the block can be resolved into two components:

The component parallel to the inclined plane, $mg \cdot \sin<img src=$ ” title=”Rendered by QuickLaTeX.com” height=”127″ width=”692″ style=”vertical-align: -6px;”/>
The component perpendicular to the inclined plane, $mg \cdot \cos<img src=$ ” title=”Rendered by QuickLaTeX.com” height=”127″ width=”692″ style=”vertical-align: -6px;”/>

The force of kinetic friction acting on the block can be calculated using the equation:

$f_k = \mu_k \cdot N$

where $f_k$ is the force of kinetic friction, $\mu_k$ is the coefficient of kinetic friction, and $N$ is the normal force.

The normal force, $N$ , can be calculated using the equation:

$N = mg \cdot \cos(\theta)$

The net force acting on the block can be calculated using the equation:

$F_{net} = mg \cdot \sin(\theta) - f_k$

The acceleration of the block, $a$ , can be calculated using Newton’s second law:

$F_{net} = ma$

Substituting the values of $F_{net}$ and $f_k$ in the equation for $a$ , we get:

$mg \cdot \sin(\theta) - \mu_k \cdot mg \cdot \cos(\theta) = ma$

Simplifying the equation, we have:

$a = g \cdot (\sin(\theta) - \mu_k \cdot \cos(\theta))$

Therefore, the acceleration of the block as it slides down the inclined plane is:

$a = g \cdot (\sin(\theta) - \mu_k \cdot \cos(\theta))$

Also Read:

Gear vs Pulley:Exhaustive Detailed Insights

January 21, 2024November 20, 2021 by Keerthi Murthi

Both pulley and gear carry the rotating motion between the two objects via rope, string, or belt.

The way of working of both gear and pulley are pretty similar. But some of the properties may change. The comparison analysis of gear vs pulley gives an account of the difference and similarities.

Comparison between gear vs pulley

The comparative analysis of gear vs pulley is given in the table below, which may help you understand gear and pulley properties.

	Gear	Pulley
Definition	The gear consists of two rotational shafts fitted with the interlocking tooth-like structures placed in an equal interval.	Pulley consists of the simple wheel or axel in which the rope or a cable moves over.
Torque	The transmission torque acting on the gear is always greater.	Since the pulley uses the string for the transmission, the torque depends on the tension acting on the string. So the transmission of torque is less.
Tension	The gear does not need any medium for transmitting the motion, so the gear system is free from the tension.	The rope or cable used in the pulley exerts tension force, which affects the motion transmission
Distance	Gears are employed, where the transmission of motion takes place in a short distance.	Pulleys are employed to transmit the motion of a longer distance.
Power loss	There will be a loss in power during transmission.	The loss of power is relatively less in the case of the pulley system.
Change in the direction	The gear can reverse the direction of the motion by turning the two shafts in the opposite direction.	Pulley can also reverse its direction by moving the load along the circumference of the wheel or axel.
Speed	The gear offers a high speed of rotation.	It isn’t easy to achieve high speed in the case of a pulley.
Lubrication	Lubrication has to be done on the gear system regularly to work efficiently.	The pulley does not require any lubrication for its better performance.
Safety	The use of a gear system is safe for transmitting the motion as the gear does not slip.	Safety in the pulley system is lesser compared to the gear system because the pulley rope slip often.
Maintenance	The cost of maintenance of the gear is more, and it has longer life.	The maintenance cost of the pulley is less, and it has a shorter life span.
Nature of the equipment	The equipment used in gear is bulky.	The pulley uses lightweight equipment.
Efficiency	The efficiency of the gear is more because power loss is less.	The efficiency of the pulley is less because there is a loss of power due to friction and tension.
Purpose	The purpose of using the gear in the mechanical system is to change the direction and speed of the system.	The purpose of the pulley is to lift the massive object, and it can also change the direction.

Some need to know facts

Both gears and pulleys exhibit rotational motion.
Gears are continuously operated in pairs.
Pulley does not provide the mechanical energy on its own it just transfers the motion.
Gear uses parallel shafts for the operation.
Gears are employed in machines, automobiles, clocks and in some manufacturing tools.
Gears are available not only in a circular shape; they have come in cone and square shapes also.

Frequently Asked Questions

What is the major advantage of gears over pulleys?

The major advantage of using gear is to achieve constant velocity.

Even though the pulley covers a more considerable distance but it is difficult to achieve constant velocity. An additional force of “friction” is acting on the pulley, which reduces the torque so that the velocity keeps changing. But in the case of gear, torque is more so we can achieve the constant velocity.

Which is more efficient, pulley or gear?

The efficiency of the gear is more than the pulley.

Since the torque acting on the gear system is more, it offers more efficiency, about 99%, but the pulley offers an efficiency of 94-96%. It is because the pulley may slip so that there will be a loss of transmission power.

What are the advantages of pulley over gear?

A pulley can be operated at a longer distance also. This is one of the main advantages of the pulley over gear.

A pulley is a simple mechanical system that can be employed easily compared to the gear. And pulleys are not too bulky to carry. And the main advantage of the pulley is that lubrication is not needed for the efficient functioning of the pulley. To change the ratio of driving and driven pulleys are more suitable than the gear.

Why is lubrication mandatory for the operation of gear?

Lubrication is the method of oiling the gear system for better performance.

Lubrication prevents the friction between the teeth of the gear system, and it controls the rise in the temperature produced due to rolling and sliding friction between the teeth.

Explain the working of gear.

A gear is a wheel with a tooth-like structure that transfers the mechanical energy from one system to another.

The gear is provided with two axels. The one is the driving wheel, and the other is the driven axel—both consisting of teeth-like structures. If the first wheel rotates in the clockwise direction, the second one also rotates in the same direction by locking the tooth of one another. These wheels turn by interlocking teeth and promote mechanical energy.

How does torque influence the gear to promote the transmission?

In order to bring the gear in motion, torque is an essential component of the gear.

Torque involved in the gear reduces the internal friction between the teeth of the axels. Hence the rotational speed increases this made to increases the mechanical transmission of motion. So that efficiency of the gear also increases proportionally.

What are the factors involved in the energy loss in a pulley?

The factor involved in the energy loss in the pulley are given below

Friction – since the pulley does not need any lubrication, there will be a regular frictional force between the wheel and the cable; this reduces the energy of the pulley.

What are the disadvantages of the gear?

As the gear has several advantages, but there are several disadvantages also.

The gears cannot be employed when a significant distance separates the two axels.
The gear system produces noise and vibration, which may sometimes affect efficiency.
The lubrication has to be done regularly for better performance.
These mechanical systems are not so flexible. It works in a limited area.

Also Read:

17 Uses of pulley: Exhaustive Detailed Insights

January 21, 2024November 17, 2021 by Keerthi Murthi

Pulleys help us to perform the task efficiently. These simple systems are used everywhere around us. Some uses of pulley are listed below.

Use of pulley to lift water from the well
Elevator
Lifting cargos
Window curtains
Fans with chains
Cranes
Extended ladders
Gym equipment
In construction sites
Flag poles
Rock climbing
Birdfeeders
Fishing rod
Pulleys in a sailing boat
Escalator
Garage doors or shutter
Theatre system
Timing belts in Automobiles
Oil derricks

Uses of pulley to lift water from the well

The oldest uses of the pulley system is lifting water from the well. It uses the moveable pulley to draw the water from the well. The rope is tied with a bucket at one end, and another end is in the hand of the user, who pulls the water. The rope and the bucket are thrown into the well, and when the bucket is full of water, the user exerts a force on the other end of the rope. The pulley axel helps the user reduce the applied force to pull the bucket filled with water. Hence makes the complete drawing of water from the well easier.

Elevator

One of the best uses of pulleys in the engineering domain is an elevator. To lift the heavyweight, high tensile ropes are used. The elevator carries heavyweights that can move up and down quickly by the pulleys. The elevator consists of several motor systems that lift the object with the mechanism of the pulley system—in the absence of a pulley, lifting the object and moving becomes a bit complicated.

Image credits: Image by Elsemargriet from Pixabay

Lifting cargos

In order to transfer the objects from one floor to another floor of multi-story buildings, the lifting cargos are very helpful. It is difficult to lift the massive object manually is very difficult. The uses of a pulley equipped in lifting cargos completes the task quickly.

Image credits: Image by 2427999 from Pixabay

Window curtains

The window curtains move smoothly up and down due to the simple pulley mechanism. A cord is attached to the wheel of the pulley, and when the cord is pulled, the curtain rises up. It is the very simplest form of use of pulley in everyday life.

Fans with chain

Fans with chains use the pulley system for their operation. The fan is fitted with two chains or cables hanging at the bottom of the fan. If you pull one chain, it makes the fan turn on, and the other one makes the fan turn off when it is pulled.

Cranes

In the construction of tall building or to lift the heavy object to greater height or to lift the vehicles the cranes are widely used. The cranes use a pulley mechanism to lift the thing. It consists of raising rope, chains, and sheaves. When the force is applied to these cables and chains, the crane lifts the object. Modern cranes are designed in such a way that they can lift complex materials beyond human capacity.

Image credits: Image by Ulrike Mai from Pixabay

Extended ladders

The most conventional uses of pulley is the extended ladders that you can see everywhere. The painters and the carpenters widely use this ladder. The rung lock system of the ladders uses the pulley mechanism. The lower end of the rung lock is fitted with the cord. This cord is extended to the top of the ladder by crossing over the pulley. The ladder can extend to a certain height by these pulley systems. Since the cord is extensible, we can easily adjust the height of the ladder accordingly.

Gym equipment

Certain gym and exercise tools make uses of pulleys in their mechanism. This equipment uses moveable pulleys for their operation. The one end of the string in the equipment is attached to the weights, and another end is given to the user through a pulley. When the user pulls the string, the string exerts the tension force, which is transferred to the body. It helps in strengthening the muscle. Not only gym equipment but some athletic training tools are also involved in the use of pulley systems.

Image credits: Image by Total Shape from Pixabay

In construction sites

Uses of pulley mechanism is very common in the construction. Since the pulleys are made to lift the massive object, pulleys are widely used in construction sites. The pulleys help to lift and dumping of the materials used for the construction. Most commonly, block and tackle pulleys are used in construction sites. The gun tackle and yard and stay tackle pulleys are widely used.

Flag poles

Another widespread uses of a pulley is a flag pole. We can not hoist the flag without a pulley. Since the flag pole is tall, a rope is tied to the flag pole along with the pulley. To unfold the flag at the top of the pole, pulleys play a vital role. When the rope is pulled, the flag moves upwards with the pulley’s help, and when the rope is dragged, the flag opens. Hoisting the flag becomes effortless because of the use of pulleys in the process.

Rock climbing

The effective uses of the pulley system is rock climbing. It isn’t easy to climb the rock because the climber has to move against gravity. It needs to exert greater force to climb the rocks. Pulleys help to do this task with ease. The climbers have attached themselves to the climbing cord, which passes over the pulley. When the climber pulls the cord downwards, the climber moves upwards with the help of the pulley. This reduces to exerting more force to climb.

Birdfeeders

The uses of pulleys are extended in the birdfeeders also. These birdfeeders are fitted with pulleys to keep the feeders at the top of the trees or poles.

It can be pulled down when it needs to be refilled. This significantly helps to feed the birds in the high trees.

Fishing rod

The fishing rods are used to catch the fishes is fitted with the pulley at the axel of the rod. The pulleys help to move the cable fitted with the hook to elongate as the axel rotates. This is the simplest form of pulley system. The modern fishing rods are formed by the gear system also.

Pulleys in a sailing boat

A simple pulley is used in the sailboats to lift the heavy sails and the cargos. Sailboat may use multiple pulleys for the lifting process. It consists of both fixed and moveable pulleys. One of the sailboats is fitted with a simple pulley and rope. When the rope is pulled downward direction, the other end of the boat is lifted. The use of pulleys also helps to ensure smooth sailing. It is because the bearing system uses the pulley mechanism in sailing boats and ships.

Escalator

The moveable steps or escalators you have seen in the shopping mall, railway station, and airports are make uses of pulley system and the gear system for their motion. The escalator’s handrail moves with the steps of the escalator when the passenger puts their hand on the handrail. At the back of the escalators, the pulleys are attached with the gears to move the escalator and the handrail to move together.

These pulleys provide tension to the escalator’s belt to rotate and move in the direction opposite to the applied force.

Garage doors or shutter

Garage doors are bulky to lift. It is a complex lift manually. The uses of a pulley system helps to move the shutter up and down. At the top of the doors, four pulleys are fitted connected to the weightless string. These pulleys help to make the process easier. When the shutter door pulls up, the exerted force applied to the pulley makes the string rotate, and the door moves up and down easily.

Theatre system

A simple curtain can be pulled manually, but raising the theatre curtain manually is highly impossible. In order to raise the curtain, several sets of pulleys are required, which are attached to the single cord. The uses of pulley helps to move the curtain upward when the cable is pulled down.

Timing belts in Automobiles

Certain parts of automobiles make uses of pulley systems for their better performance. A type of pulley called idler pulleys is widely used in vehicles. These pulleys are employed to provide tension to the drive belt. These pulleys operated against the belt direction so that the tension on the belt get reduced.

Oil derricks

Image credits: Image by Viola ‘ from Pixabay

In oil and petroleum industries, the uses of pulley systems can be found regularly. Usually, the pulleys are mounted at the top of the rig, or it can be seen in the running wire lines. To gain mechanical energy, the pulleys are arranged in blocks and tackle between the crown blocks and the traveling blocks. The block and tackle pulley provide sufficient mechanical energy to lift the heavy load. For the wireline operation, two pulleys are hung in the derrick, and the wireline runs smoothly.

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Coulomb Friction Vs Viscous Friction:Comparative Analysis

January 21, 2024November 17, 2021 by Keerthi Murthi

Friction is a force of resistance that retards the relative motion of the matter. Coulomb friction and viscous friction are the sub-division of friction force.

Though both Coulomb and viscous friction restrict the motion of the matter, they exhibit different natures. Comparing Coulomb friction vs. viscous friction leads to understanding how friction changes its properties with the matter.

Coulomb friction Vs Viscous friction

Both difference and similarities between coulomb and the viscous friction can be understood by comparative analysis. The below table gives the study of Coulomb friction vs. viscous friction.

Coulomb Friction	Viscous Friction
Coulomb friction is applicable for stiction (static friction).	Viscous friction is the another name for fluid friction.
Mass and volume are not the functions involved in the Coulomb friction.	In the case of Viscous friction, only the volume is considered; it does not depend on the mass.
Coulomb friction is zero when the speed of the surface is zero, and it moves proportional to non-zero for all values of speed.	Viscous friction directly corresponds to the speed at which the fluid flows.
The distance between the two contact surfaces makes a huge contribution to the Coulomb friction.	Since viscous friction depends on the velocity gradient, it is also influenced by the distance between the layers of the fluid.
The change in the temperature has a direct effect on the Coulomb friction.	The viscous friction is inversely influenced by the change in the temperature of the fluid.
It completely depends on the coefficient of friction of the surface.	The factor coefficient of friction does not involve in this process.
Due to the Coulomb friction evolved between the surfaces may produce heat in some cases.	Since viscous friction evolved between the two layers, it is completely an internal property and does not produce heat.
The occurrence of Coulomb friction is due to the adhesive force on the solid surface.	Cohesive force is responsible for the viscous force to occur.
The variation of Coulomb friction is due to only the relative motion between the two surfaces.	The deformation or movement of fluid layers in the viscous friction is due to the shear stress.

Definition of Coulomb Friction

Coulomb friction is a synonym for “dry friction.” It is exerted on the solid surface to restrict the lateral motion.

coulomb friction vs viscous friction — Image credits: Image by Rudy and Peter Skitterians from Pixabay

Dry friction was named coulomb friction after Charles Augustin de Coulomb proposed a model to calculate dry friction. He gives the expression of inequality as

F_f ≤ µF_n

Where; F_fis the friction force exerting between the two surfaces.

µ is the coefficient friction force. F_nis the normal force acting between the two surfaces.

Definition of viscous friction

Viscous friction is applied on the layers of both liquid and gas to restrict the relative flow of the fluid.

Image credits: Image by PublicDomainPictures from Pixabay

Frequently Asked Questions.

What are the factors that affect the coefficient of friction?

The factors that may affect the coefficient of friction are

The nature of the surface – for the smooth surfaces, the friction is less. But in the case of rough surfaces, the coefficient of friction is more compared to the smooth surface.

Temperature – the change in temperature and the coefficient friction are corresponding to each other. At higher temperatures, the coefficient of friction is also high.

What do you meant by cohesive and adhesive forces?

These are two different forces exerted on the substance can be define as below.

Cohesive force is a tendency of a substance that makes two particles of the same substance hold together by creating a force of attraction.
Adhesive force is a tendency of two dissimilar surfaces attracting one another to keep in contact with each other.

Does the coefficient of friction is applied to the viscous friction?

As the coefficient of friction is a dimensionless quantity and the viscous friction has a certain dimension. So coefficient friction is not applicable to viscous friction.

A quantity coefficient of viscosity is used to measure viscous friction. It is the ratio of shearing stress acting between the layers of the fluid and the relative velocity at which the fluid is flowing.

Does the pressure affect the viscous friction?

Under normal conditions, pressure does not affect the viscous friction acting on the fluid.

At high pressure, the intermolecular distance between the layers of the fluid decreases so that force between the molecules increases. This decreases the relative velocity between the two layers. This increases viscous friction.

A wooden block is sliding on the surface. Calculate the friction acting between the block and the surface if the normal force acting between them is 7N, and the coefficient of friction is 0.30.

Solution:

Given: Coefficient of friction µ = 0.30

Normal force F_N = 7N

The friction acting between the wooden block and the surface is given by

F = µF_N

F = 0.30 × 7

F = 2.1 N

The Coulomb friction acting on an object is 5.6N, and the normal force acting on the object is 8.1N. Find the coefficient of friction.

Solution:

Given: The friction force acting on the object is 5.6N

The Normal force acting between object and surface is 8.1N

The Coulomb friction acting on the object is given by

F_f = µF_n

5.6 = µ (8.1)

µ = 0.69

Can friction coefficient have a negative value?

Practically it is impossible for an object to have a negative value of the coefficient of friction.

In 2012, a study on the potential for friction demonstrated that for a low-load system, the normal force acting on the object and surface decreases which leads to an increase in the friction between the object and the surface. However, it contradicts the real-world experiment.

How does the distance between the two layers affect the viscous friction?

The distance between the two layers of the fluid directly corresponds to the change in the velocity between the two layers. It influences the viscous friction of the fluids.

When the fluid flows, the layers of the fluid exhibit distinct velocities. If the layers and the boundary of the fluid are closer, the shear stress acting at the boundary becomes maximum; this makes the velocity decrease. So the distance between the layers influences the viscous friction.

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Types Of Pulley:Exhaustive Insights

January 21, 2024November 17, 2021 by Keerthi Murthi

Pulley is a simple mechanical system that helps to transmit the motion of an object via rope, rod, or belt.

Pulley helps change the position and direction of an object easily. It is used only to transfer the object’s motion. It does not provide energy for the object to move. This post is concentrated on the types of the pulley.

Types Of Pulley

There are several types of pulley that are very helpful to carry the motion. The three basic types of the pulley are;

Fixed pulley
Moveable pulley
Compound pulley

Let us study these in detail.

Fixed pulley

It is one of the types of pulley system which has a pulley attached to a fixed arm and a rope is holding the weight is moving over the pulley. The fixed pulley is designed such that the wheel and the axel situate in one edge.

Working of a fixed pulley

When you pull the rope on one side, say downward, the other side of the rope moves in the upward direction. The force that you apply to pull the rope downward is equal to the force that you exert to lift the same object by your hand. In this case, the direction of force changes.

Moveable pulley

In this type of pulley consisting of a rope whose one end is fixed and other is set free to pull. This rope crosses over the pulley, which is attached to an object.

Working of moveable pulley

When the free end of the pulley is pulled down, the pulley slide over the string and uplift the object, this pulley is beneficial if you are at a higher altitude and the object is below your level. Moveable pulleys will work as wheel, if both the end of the string is fixed to the arm. In that case, when the force is applied, the object moves along the string.

Compound pulley

It is a type of pulley composed of both fixed and moveable pulley in a single system. It is employed to lift the heavy object. This pulley makes you exert less than half of the energy.

Image credits: Image by Muhammet Ali ÇETİN from Pixabay

Working of compound pulley

Since it has both fixed and movable pulleys, it makes the object lighter and becomes easy to lift. For this process, you need much speed. The compound pulley is also called as “Combinational pulley system.”

Other than the above three types, there are several types of pulley. The secondary types of pulley are

Block and Tackle pulley
Step pulley
Cone pulley
Jockey pulley
V groove pulley
Conveyor pulley
Belt pulley

Block and Tackle pulley

Block and tackle or simply tackle pulleys consists of two or more pulleys in a single system held by a rope or cable. This particular type of pulley is used to lift the massive body.

Working of block and tackle pulley

Several sets of pulleys combined together to form a block. This block, along with a rope crossing over the pulley, is called a tackle. These blocks are paired in such a way that one pulley is fixed and another is to be moveable. The load is attached to the moveable arm of the pulley. The rope provides mechanical support to the system and boosts the tension force on the rope to lift the massive body.

This type of pulley is commonly used in boats, cranes, and sailing ships.

Step pulley

A step pulley consists of several pulleys of various diameters fixed to one arm. It is arranged in such a way that it looks like a step, so the pulley is named a step pulley.

Working of step pulley

Step pulley is provided with a belt. The belt is changed from one step to another step to monitor the speed of the system. Step pulleys are always operated in pairs. When the belt of the one pulley is changed, the belt of other pulleys is also changed simultaneously. These pulleys are employed to regulate the speed of the pulleys.

This types of pulley is commonly equipped in the machines such as drilling machines, lathe machines, etc.

Cone pulley

It is a type of pulley that acts in pairs. Cone pulleys are usually narrow and cut into two parts. The pulleys are arranged as the broad end of the one cone is facing the narrow end of the other one. It is provided with a belt that moves with the pulley and controls the speed of the system.

Jockey pulley

A jockey pulley consists of a wheel at the top edge and a belt attached to it. This type of pulley is also used to regulate the speed of the machinery.

Working of jockey pulley

Jockey pulleys are fitted with five pulleys, which are operated by coupling with other pulley. While running the machine, the belt may become loose and slip from the pulley. The third pulley, a self-controlled pulley, is used in pairing with the two pulleys to overcome this problem.

V groove pulley

This typical types of pulley consists of a “V” shaped belt is used to move over the two pulleys. This is particularly equipped in automobiles and electric motors to transmit power between the parallel axels of the pulley.

Image credits: Image by b0red from Pixabay

Working of V-groove pulley

The V belt used in the system provides the mechanical linkage. This delivers excellent speed and load capacity to the system. Heavy load increases the efficiency by transmitting power through the belt, which is responsible for reducing friction.

Conveyor pulley

Conveyor pulleys are used for the driving purpose equipped in the countershaft of the machines. It consists of broad and flat belts on their face.

Working of conveyor pulley

It is type of pulley consisting of a roller and a flexible disc. The conveyor belt helps to change the direction of the pulley and provides tension. The disc and the roller are fitted in the end-to-end connection, which allows for rolling over the conveyor motors. These are used in the oil engine and electric motors.

Belt pulley

It is the most inexpensive pulley used in the computer printers, papermakers, and textile industries.

It consists of a flat belt that moves over a flat pulley. It is operated at high speed and uses low power. The torque acting on the pulley is more, so that, if the belt slipped, there would be very little damage to the equipment.

The belt pulleys are further classified into three types, they are

Split pulley
Wooden pulley
Paper pulley

Split pulley

It is a type of pulley. It is made up of cast iron, consisting of two parts, one is a face, and another is a hub. These are versatile pulley, operates efficiently in all size of the pulley. It is mainly used in saw machines and oil extraction.

Wooden pulley

The wooden pulleys are lightweight pulleys made up of wood. These are fitted with adjustable screws to reduce friction.

Paper pulley

In this type of pulley, the inner layer of the pulley is comprised of metal coat and outer layer is coated with the paper fibers. The paper fibers are compressible, and they transfer the motion from the center to the shaft in a short distance.

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15 Dry Friction Example: Interesting Analysis

January 20, 2024November 9, 2021 by Keerthi Murthi

Dry friction is the resistive force that encounters between the two solid surfaces. We can observe dry friction around us.

Earth gravitational pull is also an example of dry friction. We can experience the dry friction while you are walking, brushing, rubbing, sanding, etc. Without dry friction, we cannot imagine our life. Some dry friction examples are listed in this post.

Dry Friction Example

Lightning matchsticks
Brushing teeth
Ironing clothes
Writing on a paper
Mopping the floor
Rubbing hands
Ball-bearing
Page flipping
Kid’s slide
Walking on ground
Sanding
Cycling on the road
Brakes on the automobiles
Tug of war
Climber plants
Gecko lizards on the wall
Forest fire
Water well pulley

Lightning matchsticks

When the matchsticks are a strike against the rough surface, dry friction is created. Stick catches fire due to the friction. It is an example of kinetic friction, which is converted into heat energy.

Brushing teeth

Some sticky particles are deposited on the teeth, which is very challenging to remove. Brushing creates a maximum force to overcome the dry friction acting on the particles, and it is removed from the teeth.

Ironing clothes

When we start to iron the clothes, friction permits us to create pressure on the wrinkles on the clothes. The pressure eliminates the wrinkles. If the dry friction is absent, the iron box slides over the clothes. The pressure exerted on the clothes affect the friction acting on the wrinkles. This pressure directly related to the friction force.

Writing on a paper

An essential application of friction is writing on paper. The friction acting between the paper and the pen allows the ink molecules to stick on the paper surface.

Mopping the floor

The deposition of dirt and some particles on the floor are difficult to remove by normal dusting. Mopping with water creates a force to overcome the friction on the dust, and it is removed from the floor. The friction acting on the dust particles is static friction. It is one of the major household dry friction example.

Rubbing hands

Rubbing hands is a very good kinetic friction example. This is associated with the production of heat—the friction developed by rubbing causes to keep the hands warm.

Ball-bearing

If the friction acting on the machines is more, ball-bearing is used to reduce the friction. It uses the method of rolling friction. These are used in almost all the machines for ease move and to work smoothly. So ball-bearing is a dry friction example used in machines.

Page flipping

Flipping pages from one page to another, friction is necessary. The friction between the two pages allows us to flip to the next page. Without friction, flipping becomes complicated; the page might slip from our hands.

Image credits: Image by StockSnap from Pixabay

Kid’s slide

Sliding over the kid’s slides is very joyful that we are all enjoyed in our childhood days. Sliding friction is acting over the kid’s slide. When we slide down, the friction retards our motion and stops the immediate falling down.

Image credits: Image by Lena Helfinger from Pixabay

Walking on ground

A very important dry friction example in every day life is walking. We are walking firmly on the ground due to friction force. Walking in the desert is difficult because the friction between our foot and sand offer low friction. So it is clear that friction is very necessary to walk on the ground.

Sanding

Sanding is a process to achieve the smoothness from the hard material. It is used to rub the wooden surface and edges. The irregularity in the wooden surface is broken downs by the rough surface of the sandpaper, and hence the surface and the edge become smooth. This is used to reduce friction.

Cycling on the road

When we ride on the cycle, we start, stop, and can turn whenever we need. Friction acting between the cycle tire and road prevents from skidding on the road. The asymmetry on the cycle tire provides the necessary grip to hold on the road. Gripping allows the cycle to overcome from the friction because it has low value of friction coefficient.

Brakes on the automobiles

Brakes are another major dry friction example .The principle involved in the brakes of automobiles is friction. There is friction acting between the brake pad, and the wheel exerted when you apply, making the automobile stop the motion.

Tug of war

It is a game where two teams pull a rope on their side. There is friction between the hands of the people and the rope, which helps to hold a rope and provide grip to exert a force to pull. Since friction acting between the two solid surface it is a dry friction example.

Image credits: Image by Xuan Duong from Pixabay

Climber plants

ivy g61480be71 640 — Image credits: Image by analogicus from Pixabay

We can see varieties of climber plants in nature, it is natural dry friction example. They can easily climb the wall, trees, gates, etc. it is because of friction. They generally use the rough surface to climb.

Gecko lizards on the wall

The gecko lizards climb the wall vertically so easily because of the friction. The frictional force between the leg and the wall is so strong so that it provides the grip to climb the wall.

Forest fire

Sometimes, the forest catches fire automatically because of the friction. When two trees rub each other, a frictional force is produced, which turn into thermal energy resulting in fire catching.

Water well pulley

Image credits: Image by ddzphoto from Pixabay

An excellent example of rolling friction is the water well pulley. A rope is tied with a bucket full of water is drawn from the well with the help of a pulley. It is easy to pull out the bucket from the well due the friction force acting between the rope and the pulley.

Also Read:

Key Takeaways

Where is Friction Not Useful?

In Sports

For Skateboarders

In Airplanes

Where There is No Friction

Where Friction is Not Helpful

In Swimming

In Everyday Life

Where Friction is Used in Everyday Life

Interesting Facts about Friction

Friction is Everywhere

Friction Can Be Both Helpful and Harmful

Friction Generates Heat

Friction Can Be Reduced

Friction Can Be Overcome

Friction Affects Motion

Friction Can Cause Wear and Tear

Friction is Essential for Walking

Friction Can Create Sound

Friction is Essential for Writing

Where is friction not useful and what are some techniques to reduce friction effectively?

Frequently Asked Questions

When is friction not useful in sports?

Where is friction not a good thing for a skateboarder?

Why is air resistance friction not useful for an airplane?

Where is there no friction?

Where is friction not helpful?

Why is friction not useful in swimming?

When is friction not useful in everyday life?

Where is friction used in everyday life?

What are some sports where friction is not useful?

How is friction not useful when ice skating?

Why is friction not always useful?

Can you provide two examples where friction is not useful?

Is friction not useful in skiing?

Where is friction useful?

How to find coefficient of friction given velocity and distance moved by the object

Solved Problems On Coefficient Of Friction

An object of mass of 2kg is moving with a velocity of 12ms-2, the friction force acting on the body make the object stop at a distance of 22m. Find the coefficient of friction and hence calculate the friction force. The acceleration due to gravity g given as 10ms-2.

Find the coefficient of friction given velocity and distance as 28ms-2 and 34m respectively and hence find the normal reaction and the friction force. (Given: Mass of the object is 4kg and Acceleration due to gravity is 10 ms-2).

A body of mass of 12kg is moving on a rough surface. It travelled a distance of 72m, and then its motion is hindered by the friction force of 45N. Calculate the coefficient of friction and hence find the velocity at which the body is moving.

The coefficient of friction is 0.46, and the mass of the object is 7kg. The object is moving with a constant velocity of 46 ms-2. Calculate the distance travelled by the object after friction retards the object’s motion.

How to find coefficient of kinetic friction

How to calculate uncertainty of coefficient of kinetic friction

How to calculate coefficient of kinetic friction without mass

Determining the Coefficient of Kinetic Friction on an Inclined Plane

How to Find the Coefficient of Kinetic Friction with Acceleration

How to Find the Coefficient of Kinetic Friction Without Friction Force

Worked-out Example

How to Find the Coefficient of Kinetic Friction Using Velocity and Distance

Worked-out Example

How to Find the Coefficient of Kinetic Friction Using Mass and Force

Worked-out Example

Frequently Asked Questions

Does the calculation of kinetic friction without mass give the same value of coefficient obtained by considering the mass?

Does the nature of the material influence the coefficient of kinetic friction?

What is necessary to find the coefficient of kinetic friction of a moving object?

Can the value of the coefficient of kinetic friction be greater than 1?

Does greater coefficient of kinetic friction lead to energy dissipation?

What is the coefficient of friction?

How can I calculate the coefficient of friction?

What is the difference between kinetic and static friction?

What is the formula for the coefficient of kinetic friction?

How can I find the coefficient of kinetic friction for a moving object on a flat surface?

What is the equation for calculating the force of kinetic friction?

How can I find the coefficient of static friction?

What is the relationship between the coefficients of static and kinetic friction?

How can I solve a friction problem using the coefficient of friction?

Comparison between the Kinetic Friction vs Kinetic Force

Definition of kinetic friction and kinetic force

Interesting facts to remember

Frequently asked questions

Does the kinetic friction remain constant throughout the motion?

Does the increase in speed increase the kinetic friction?

How does the kinetic energy increase with the kinetic force?

What is the major application of kinetic friction?

How does kinetic friction be responsible for the motion?

Does the mechanical energy is conserved in the kinetic friction?

How does the kinetic energy equal to the kinetic friction?

An object of mass of 2kg is moving with a velocity of 12ms^-2, the friction force acting on the body make the object stop at a distance of 22m. Find the coefficient of friction and hence calculate the friction force. The acceleration due to gravity g given as 10ms^-2.

Find the coefficient of friction given velocity and distance as 28ms^-2 and 34m respectively and hence find the normal reaction and the friction force. (Given: Mass of the object is 4kg and Acceleration due to gravity is 10 ms^-2).

The coefficient of friction is 0.46, and the mass of the object is 7kg. The object is moving with a constant velocity of 46 ms^-2. Calculate the distance travelled by the object after friction retards the object’s motion.