The force of friction is encountered literally at every step. But do people know why it is needed? What is the harm and benefit of friction force? Let's try to figure it out.
Foreword
Several forces act on terrestrial objects, which are closely interconnected and affect the vital activity of bodies. First of all, it is gravity, elasticity (internal resistance of bodies in response to the displacement of their molecules) and support reactions. But there is also a very important physical quantity called the friction force. It, unlike the force of gravity and elasticity, does not depend on the location of the bodies. When studying it, other laws apply: the coefficient of sliding friction and the reaction force of the support. For example, if you need to move a heavy cabinet, then from the very first minute it will become clear that this is not easy to do. In addition, there are certain interferences when performing this task. What hinders the efforts applied to the cabinet? And this is hindered by nothing more than the force of friction, the principle of which is studied at school. The course of physics for grade 7 talks in detail about this phenomenon.
Ambiguous question
What is the harm and benefit of any type of friction force? Of course, the examples given are somewhat exaggerated - in life everything is a little more complicated. However, despite the fact that the friction force has obvious disadvantages that create a number of difficulties in life, it is clear that without it there would be much more problems. Therefore, this value has its advantages and disadvantages.
Negative Examples
Among the examples of the harm of this force, one of the first places is the problem of moving heavy loads, the rapid wear of favorite things, and the impossibility of creating a perpetual motion machine, because due to friction, any movement sooner or later stops, requiring third-party intervention.
Positive points
Among the examples of the usefulness of this power is that we can safely walk on the ground without slipping at every step, our clothes are firmly seated and do not instantly become unusable, since the threads of the fabric are held by friction. In addition, people use the principle of this force by sprinkling slippery roads, due to which it is possible to avoid many accidents and injuries.
conclusions
Mankind has learned to interact with this physical quantity, increasing and decreasing it depending on the goals set. Our immediate task is to try to use it as efficiently as possible.
What is under our feet?
People encounter it very often. The benefit of friction is that we would not even be able to take a step without this physical quantity. It is she who keeps our shoes on the surface where we step. Each of us has walked on very slippery surfaces, for example, on ice, and knows firsthand that it is very difficult. Why is this happening? Before we talk about the harm and benefits of friction force, let's define what it is.
The essence of the concept
The force of friction is the interaction of two bodies that occurs at the point of their contact and prevents their movement relative to each other. There are several types of friction - rest, sliding and rolling.
Causes
The first reason is the constant surface roughness. It is this indicator that affects what kind of friction force will take place. If we are talking about smooth surfaces, such as a metal-plated roof or icy areas, then their roughness is almost invisible, but this does not mean that it is not there - it is present at a microscopic level. In this case, the force of sliding friction will act. But if we talk about a cabinet standing on a carpet, then here the roughness of the two objects will significantly impede mutual movement. The second reason is the electromagnetic molecular repulsion that occurs at the point of contact between objects.
Friction of rest
What happens when we try to move a closet, but we cannot move it even a centimeter. What keeps an object in one place? This is the static friction force. The fact is that the applied efforts are compensated by the dry friction force that occurs between the cabinet and the floor.
Harm and benefit of static friction force
It is the static friction force that does not allow the laces on our shoes to untie on their own, the nail that we have just driven into the wall to fall out, and keeps the closet in place. Without it, it would be impossible for people, animals, or cars to move on the earth's surface. Friction damage is also present. It happens on a fairly global scale, for example, the static friction force can lead to deformation of ship plating.
Scientific rationale
In order to move the cabinet, it is necessary to apply a force to it that will overcome friction. That is, as long as the applied force is less than the friction force, the furniture will remain in place. In addition to these factors, there is also the reaction force of the support, which is directed perpendicular to the plane. It depends on the material from which the floor is made (here, the elastic force is also involved). There is also a coefficient of friction, depending on what the two surfaces that interact with each other consist of. Therefore, the friction force acting on the cabinet is equal to the coefficient of friction, which is multiplied by the reaction force of the support (surface).
Sliding friction
So, to overcome the friction, we asked someone to help us move the closet. What have we discovered? That after we applied a force that exceeded the static friction force, the cabinet not only shifted, but also continued to move in the necessary direction for some time, of course, with our help. And the effort spent was about the same throughout the entire journey. In this case, we were prevented by the sliding friction force directed in the opposite direction from the applied action. It is worth noting that its resistance is much lower than that of the static friction force. To reduce this figure, if necessary, various lubricants are used.
Rolling friction force
If we remember that someday we will have to move the cabinet back, we decide to equip it with wheels. In this case, the resulting interaction will be called rolling friction, since the object will no longer slide, but roll on the surface. The rolling wheels will be pressed into the carpet a little, forming a tubercle that we will need to overcome. This determines the force of rolling friction. Of course, if we roll the cabinet not on the carpet, but, for example, on the parquet, then it will be even easier to move it, due to the fact that the parquet surface is harder than the carpet surface. For the same reason, it is much easier for cyclists to ride on a highway than on a fine sand beach.
The harm and benefits of friction force
Not going - just going
Because it's icy
But it falls great!
Why isn't anyone happy?
Such a naive nursery rhyme at first glance - and how much it contains, if you look at it from physical point vision! After all, it is precisely in it that the system of a contradictory attitude to the notorious force of friction is contained. This constant battle, where two concepts compete with each other - the harm and the benefits of the force of friction, will never have a winner. After all, what is convenient and beneficial for one person is often quite the opposite for another - bad, as in this poem.
Remember the story of Nikolai Nosov about the ice slide that the guys built in the yard? And when they all left for dinner, the one who did not participate in the construction came out. He tried to climb on it, but only hurt himself, but he could not climb. And the kid guessed to sprinkle sand on the ice - it became very convenient to climb to the very top even on ice! Thus, by increasing the force of friction between slippery ice and the sole, the boy realized that the use of friction allows you to overcome obstacles.
But after lunch, the kids came out with ice cubes to ride their slide to their heart's content. But it wasn’t there: the sled does not go on the sand! For them, this situation turned the other way, showing the harm of friction.
We observe similar cases in winter, when the boys roll out ice paths and rush along them with a run, covering the distance in a matter of minutes! And then elderly people hobble, slip on the snow-covered rolls and fall, breaking their arms and legs. Here you go again illustrative examples, where in the same case both the harm and the benefit of the friction force coexist.
It is to reduce the friction force that skiers lubricate their skis with special ointments in order to increase speed when moving. Skating rinks, where skaters or figure skaters are engaged, are periodically watered and cleaned - also to reduce friction. And footpaths, on the contrary, are sprinkled with sand or ash so that no one falls on them. Some innovators even came up with the idea of gluing pieces of sandpaper to the soles of winter boots and boots just to increase the friction force.
The same thing happens with the wheels of cars. It's no secret that with the onset of winter, drivers "shoe" their iron horses in a special winter tires". Otherwise, without useful power friction increases braking distances, the car skids when cornering, it uses, and often the driver does not manage well. And how the accident ends, everyone knows for himself.
Something we are all about winter, but about ice, but about falling. But are there other moments in everyday life where you can clearly see how the harm and benefit of the force of friction compete with each other? Of course have! They are everywhere. Even in our room.
Here, for example, is a huge and heavy wardrobe. It stands to itself, as if rooted to the spot, and does not move. And if the force of friction suddenly disappeared, what could happen then? And this hulk would have gone from the lightest push around the room! And it is still unknown if we could manage to dodge it. good strength friction, useful!
But my mother decided to rearrange the furniture. And you need to move this notorious closet to another wall. One, two, take it! Three - four, tensed up! Only everything turns out to be useless: the heavier the object, the stronger the friction force holds on to it. Terrible, nasty force!
Again they compete with each other - the harm and benefit of the force of friction. No competition needed! You just need to know physical laws well and be able to extract practical benefits from this knowledge. Not needed in this moment friction force? So, it should be reduced: to make the contact surfaces smoother, slippery. For this, someone advises smearing the floor with soap or oil, someone puts a wet rag under the legs of a heavy object. And now - one - two - and you're done! Moved quite easily a sort of colossus from its place.
The force of friction constantly accompanies us throughout life, just like the force of gravity. Somewhere it creates inconvenience for us, but somewhere it is impossible to do without it. But be that as it may, it exists, and our task is to learn how to use physical laws in such a way that our life becomes more convenient and comfortable.
Friction is not always a bad thing. significant, and sometimes friction is simply necessary.
The Benefits of Friction - Examples
Once, a car was driving along the highway, loaded with three-meter rails. The rails protruded through the open tailgate. From the side it was noticeable that the truck was moving somehow uncertainly, roaring from side to side as if the driver was unable to cope with the steering. Here the car suddenly switched to left side road, the driver applied the brakes, the car leveled off and returned to the right side. But as soon as the driver increased the speed again, the car again began to wag to the right, to the left; the driver - on the brake, but, apparently, did not have time, and the truck buried itself in a ditch. The ditch was shallow. There was no serious accident. The driver turned on the stalled engine and in reverse got out on the highway. Then he stopped the car on the side of the road and began to look around - why did the car stop listening to the steering wheel? He checked steering- everything was OK; I went to inspect the cargo ... Suddenly, throwing off his jacket, he began to shift the rails. He guessed what it was. From the shaking, the rails slid back, and the front of the car began to rise. A little more - and the car would be "on its hind legs". The front wheels rolled, barely touching the ground. With each push, they completely lost traction with the ground. The friction between the front wheels and the road has become negligible; that's why the car lost control. The reason was in lack of friction. Friction often plays very important role, (more details: ). If the friction of the wheels on the rails is low on the locomotive, the wheels will begin to slip and the locomotive will not be able to move the train. Out of habit, it is difficult to walk quickly on a smooth, waxed parquet floor - the legs slip and do not provide the necessary support.The road turns the car
The driver, turning the steering wheel of the car, thereby causes his front wheels to turn. They are no longer along the road, but slightly sideways. The car, by inertia, tends to continue moving in the same direction, but the front wheels have turned and meet significant resistance from the road. Friction force the road turns the whole car in the direction in which the driver turns it.Water resistance force
Airplanes, steamships and simple boats also use the force of friction and water resistance force or air when they need to change the direction of their movement. For this they have a steering wheel. While the boat is moving straight, its rudder is in motion and encounters almost no resistance from the water: the jets easily flow around it. But as soon as the steering wheel turns to the side, water jets begin to run into one of its planes - significant water resistance, and its pressure pushes the rudder, and with it the stern of the boat, in the opposite direction to the rudder. The bow of the boat is heading in the same direction as the rudder is turned. On large ships, the forces generated by turning the rudder are so great that a person is not able to hold the steering wheel in his hands. Help comes Steam engine or Electrical engine. On large ships, special steering machines are installed that turn the steering wheel, and here, too, a person evaluates the benefits of variousForeword
Ambiguous question
Negative Examples
Positive points
conclusions
What is under our feet?
The essence of the concept
Causes
Friction of rest
Scientific rationale
Sliding friction
Rolling friction force
The harm and benefits of friction force
Not going - just going
Because it's icy
But it falls great!
Why isn't anyone happy?
The force of friction is encountered literally at every step. But do people know why it is needed? What is the harm and benefit of friction force? Let's try to figure it out.
Foreword
Several forces act on terrestrial objects, which are closely interconnected and affect the vital activity of bodies. First of all, it is gravity, elasticity (internal resistance of bodies in response to the displacement of their molecules) and support reactions. But there is also a very important physical quantity called the friction force. It, unlike the force of gravity and elasticity, does not depend on the location of the bodies. When studying it, other laws apply: the coefficient of sliding friction and the reaction force of the support. For example, if you need to move a heavy cabinet, then from the very first minute it will become clear that this is not easy to do. In addition, there are certain interferences when performing this task. What hinders the efforts applied to the cabinet? And this is hindered by nothing more than the force of friction, the principle of which is studied at school. The course of physics for grade 7 talks in detail about this phenomenon.
What is under our feet?
People encounter it very often. The benefit of friction is that we would not even be able to take a step without this physical quantity. It is she who keeps our shoes on the surface where we step. Each of us has walked on very slippery surfaces, for example, on ice, and knows firsthand that it is very difficult. Why is this happening? Before we talk about the harm and benefits of friction force, let's define what it is.
The essence of the concept
The force of friction is the interaction of two bodies that occurs at the point of their contact and prevents their movement relative to each other. There are several types of friction - rest, sliding and rolling.
Causes
The first reason is the constant surface roughness. It is this indicator that affects what kind of friction force will take place. If we are talking about smooth surfaces, such as a metal-plated roof or icy areas, then their roughness is almost invisible, but this does not mean that it is not there - it is present at a microscopic level. In this case, the force of sliding friction will act. But if we talk about a cabinet standing on a carpet, then here the roughness of the two objects will significantly impede mutual movement. The second reason is the electromagnetic molecular repulsion that occurs at the point of contact between objects.
Friction of rest
What happens when we try to move a closet, but we cannot move it even a centimeter. What keeps an object in one place? This is the static friction force. The fact is that the applied efforts are compensated by the dry friction force that occurs between the cabinet and the floor.
Harm and benefit of static friction force
It is the static friction force that does not allow the laces on our shoes to untie on their own, the nail that we have just driven into the wall to fall out, and keeps the closet in place. Without it, it would be impossible for people, animals, or cars to move on the earth's surface. Friction damage is also present. It happens on a fairly global scale, for example, the static friction force can lead to deformation of ship plating.
Scientific rationale
In order to move the cabinet, it is necessary to apply a force to it that will overcome friction. That is, as long as the applied force is less than the friction force, the furniture will remain in place. In addition to these factors, there is also the reaction force of the support, which is directed perpendicular to the plane. It depends on the material from which the floor is made (here, the elastic force is also involved). There is also a coefficient of friction, depending on what the two surfaces that interact with each other consist of. Therefore, the friction force acting on the cabinet is equal to the coefficient of friction, which is multiplied by the reaction force of the support (surface).
Sliding friction
So, to overcome the friction, we asked someone to help us move the closet. What have we discovered? That after we applied a force that exceeded the static friction force, the cabinet not only shifted, but also continued to move in the necessary direction for some time, of course, with our help. And the effort spent was about the same throughout the entire journey. In this case, we were prevented by the sliding friction force directed in the opposite direction from the applied action. It is worth noting that its resistance is much lower than that of the static friction force. To reduce this figure, if necessary, various lubricants are used.
Rolling friction force
If we remember that someday we will have to move the cabinet back, we decide to equip it with wheels. In this case, the resulting interaction will be called rolling friction, since the object will no longer slide, but roll on the surface. The rolling wheels will be pressed into the carpet a little, forming a tubercle that we will need to overcome. This determines the force of rolling friction. Of course, if we roll the cabinet not on the carpet, but, for example, on the parquet, then it will be even easier to move it, due to the fact that the parquet surface is harder than the carpet surface. For the same reason, it is much easier for cyclists to ride on a highway than on a fine sand beach.
Ambiguous question
What is the harm and benefit of any type of friction force? Of course, the examples given are somewhat exaggerated - in life everything is a little more complicated. However, despite the fact that the friction force has obvious disadvantages that create a number of difficulties in life, it is clear that without it there would be much more problems. Therefore, this value has its advantages and disadvantages.
Negative Examples
Among the examples of the harm of this force, one of the first places is the problem of moving heavy loads, the rapid wear of favorite things, and the impossibility of creating a perpetual motion machine, because due to friction, any movement sooner or later stops, requiring third-party intervention.
Positive points
Among the examples of the usefulness of this power is that we can safely walk on the ground without slipping at every step, our clothes are firmly seated and do not instantly become unusable, since the threads of the fabric are held by friction. In addition, people use the principle of this force to sprinkle slippery roads, which avoids many accidents and injuries.
conclusions
Mankind has learned to interact with this physical quantity, increasing and decreasing it depending on the goals set. Our immediate task is to try to use it as efficiently as possible.
Not going - just going
Because it's icy
But it falls great!
Why isn't anyone happy?
Such a naive nursery rhyme at first glance - and how much it contains when you look at it from a physical point of view! After all, it is precisely in it that the system of a contradictory attitude to the notorious force of friction is contained. This constant battle, where two concepts compete with each other - the harm and the benefits of the force of friction, will never have a winner. After all, what is convenient and beneficial for one person is often quite the opposite for another - bad, as in this poem.
Remember the story of Nikolai Nosov about the ice slide that the guys built in the yard? And when they all left for dinner, the one who did not participate in the construction came out. He tried to climb on it, but only hurt himself, but he could not climb. And the kid guessed to sprinkle sand on the ice - it became very convenient to climb to the very top even on ice! So, having increased the force of friction between the slippery ice and the sole with the help of sand, the boy realized that the use of friction allows him to overcome obstacles.
But after lunch, the kids came out with ice cubes to ride their slide to their heart's content. But it wasn’t there: the sled does not go on the sand! For them, this situation turned the other way, showing the harm of friction.
We observe similar cases in winter, when the boys roll out ice paths and rush along them with a run, covering the distance in a matter of minutes! And then elderly people hobble, slip on the snow-covered rolls and fall, breaking their arms and legs. Here again are illustrative examples, where in the same case both the harm and the benefit of the force of friction coexist.
It is to reduce the friction force that skiers lubricate their skis with special ointments in order to increase speed when moving. Skating rinks, where skaters or figure skaters are engaged, are periodically watered and cleaned - also to reduce friction. And footpaths, on the contrary, are sprinkled with sand or ash so that no one falls on them. Some innovators even came up with the idea of gluing pieces of sandpaper to the soles of winter boots and boots just to increase the friction force.
The same thing happens with the wheels of cars. It's no secret that with the onset of winter, drivers "shoe" their iron horses in special "winter tires". Otherwise, without a useful friction force, the braking distance increases, the car skids when cornering, it drives, and often the driver does not manage well. And how the accident ends, everyone knows for himself.
Something we are all about winter, but about ice, but about falling. But are there other moments in everyday life where you can clearly see how the harm and benefit of the force of friction compete with each other? Of course have! They are everywhere. Even in our room.
Here, for example, is a huge and heavy wardrobe. It stands to itself, as if rooted to the spot, and does not move. And if the force of friction suddenly disappeared, what could happen then? And this hulk would have gone from the lightest push around the room! And it is still unknown if we could manage to dodge it. Good friction force, useful!
But my mother decided to rearrange the furniture. And you need to move this notorious closet to another wall. One, two, take it! Three - four, tensed up! Only everything turns out to be useless: the heavier the object, the stronger the friction force holds on to it. Terrible, nasty force!
Again they compete with each other - the harm and benefit of the force of friction. No competition needed! You just need to know physical laws well and be able to extract practical benefits from this knowledge. Is friction force not needed at the moment? So, it should be reduced: to make the contact surfaces smoother, slippery. For this, someone advises smearing the floor with soap or oil, someone puts a wet rag under the legs of a heavy object. And now - one - two - and you're done! Moved quite easily a sort of colossus from its place.
The force of friction constantly accompanies us throughout life, just like the force of gravity. Somewhere it creates inconvenience for us, but somewhere it is impossible to do without it. But be that as it may, it exists, and our task is to learn how to use physical laws in such a way that our life becomes more convenient and comfortable.
home » Benefits and harms » Benefits and harms of friction force table
The harm and benefits of friction force: sliding, rest and rolling friction
The force of friction is encountered literally at every step. But do people know why it is needed? What is the harm and benefit of friction force? Let's try to figure it out.
Foreword
Several forces act on terrestrial objects, which are closely interconnected and affect the vital activity of bodies. First of all, it is gravity, elasticity (internal resistance of bodies in response to the displacement of their molecules) and support reactions. But there is also a very important physical quantity called the friction force. It, unlike the force of gravity and elasticity, does not depend on the location of the bodies. When studying it, other laws apply: the coefficient of sliding friction and the reaction force of the support. For example, if you need to move a heavy cabinet, then from the very first minute it will become clear that this is not easy to do. In addition, there are certain interferences when performing this task. What hinders the efforts applied to the cabinet? And this is hindered by nothing more than the force of friction, the principle of which is studied at school. The course of physics for grade 7 talks in detail about this phenomenon.
What is under our feet?
People encounter it very often. The benefit of friction is that we would not even be able to take a step without this physical quantity. It is she who keeps our shoes on the surface where we step. Each of us has walked on very slippery surfaces, for example, on ice, and knows firsthand that it is very difficult. Why is this happening? Before we talk about the harm and benefits of friction force, let's define what it is.
The essence of the concept
The force of friction is the interaction of two bodies that occurs at the point of their contact and prevents their movement relative to each other. There are several types of friction - rest, sliding and rolling.
Causes
The first reason is the constant surface roughness. It is this indicator that affects what kind of friction force will take place. If we are talking about smooth surfaces, such as a metal-plated roof or icy areas, then their roughness is almost invisible, but this does not mean that it is not there - it is present at a microscopic level. In this case, the force of sliding friction will act. But if we talk about a cabinet standing on a carpet, then here the roughness of the two objects will significantly impede mutual movement. The second reason is the electromagnetic molecular repulsion that occurs at the point of contact between objects.
Friction of rest
What happens when we try to move a closet, but we cannot move it even a centimeter. What keeps an object in one place? This is the static friction force. The fact is that the applied efforts are compensated by the dry friction force that occurs between the cabinet and the floor.
Harm and benefit of static friction force
It is the static friction force that does not allow the laces on our shoes to untie on their own, the nail that we have just driven into the wall to fall out, and keeps the closet in place. Without it, it would be impossible for people, animals, or cars to move on the earth's surface. Friction damage is also present. It happens on a fairly global scale, for example, the static friction force can lead to deformation of ship plating.
Scientific rationale
In order to move the cabinet, it is necessary to apply a force to it that will overcome friction. That is, as long as the applied force is less than the friction force, the furniture will remain in place. In addition to these factors, there is also the reaction force of the support, which is directed perpendicular to the plane. It depends on the material from which the floor is made (here, the elastic force is also involved). There is also a coefficient of friction, depending on what the two surfaces that interact with each other consist of. Therefore, the friction force acting on the cabinet is equal to the coefficient of friction, which is multiplied by the reaction force of the support (surface).
Sliding friction
So, to overcome the friction, we asked someone to help us move the closet. What have we discovered? That after we applied a force that exceeded the static friction force, the cabinet not only shifted, but also continued to move in the necessary direction for some time, of course, with our help. And the effort spent was about the same throughout the entire journey. In this case, we were prevented by the sliding friction force directed in the opposite direction from the applied action. It is worth noting that its resistance is much lower than that of the static friction force. To reduce this figure, if necessary, various lubricants are used.
Rolling friction force
If we remember that someday we will have to move the cabinet back, we decide to equip it with wheels. In this case, the resulting interaction will be called rolling friction, since the object will no longer slide, but roll on the surface. The rolling wheels will be pressed into the carpet a little, forming a tubercle that we will need to overcome. This determines the force of rolling friction. Of course, if we roll the cabinet not on the carpet, but, for example, on the parquet, then it will be even easier to move it, due to the fact that the parquet surface is harder than the carpet surface. For the same reason, it is much easier for cyclists to ride on a highway than on a fine sand beach.
Ambiguous question
What is the harm and benefit of any type of friction force? Of course, the examples given are somewhat exaggerated - in life everything is a little more complicated. However, despite the fact that the friction force has obvious disadvantages that create a number of difficulties in life, it is clear that without it there would be much more problems. Therefore, this value has its advantages and disadvantages.
Negative Examples
Among the examples of the harm of this force, one of the first places is the problem of moving heavy loads, the rapid wear of favorite things, and the impossibility of creating a perpetual motion machine, because due to friction, any movement sooner or later stops, requiring third-party intervention.
Positive points
Among the examples of the usefulness of this power is that we can safely walk on the ground without slipping at every step, our clothes are firmly seated and do not instantly become unusable, since the threads of the fabric are held by friction. In addition, people use the principle of this force to sprinkle slippery roads, which avoids many accidents and injuries.
conclusions
Mankind has learned to interact with this physical quantity, increasing and decreasing it depending on the goals set. Our immediate task is to try to use it as efficiently as possible.
The harm and benefits of friction force
Not going - just going
Because it's icy
But it falls great!
Why isn't anyone happy?
Such a naive nursery rhyme at first glance - and how much it contains when you look at it from a physical point of view! After all, it is precisely in it that the system of a contradictory attitude to the notorious force of friction is contained. This constant battle, where two concepts compete with each other - the harm and the benefits of the force of friction, will never have a winner. After all, what is convenient and beneficial for one person is often quite the opposite for another - bad, as in this poem.
Remember the story of Nikolai Nosov about the ice slide that the guys built in the yard? And when they all left for dinner, the one who did not participate in the construction came out. He tried to climb on it, but only hurt himself, but he could not climb. And the kid guessed to sprinkle sand on the ice - it became very convenient to climb to the very top even on ice! So, having increased the force of friction between the slippery ice and the sole with the help of sand, the boy realized that the use of friction allows him to overcome obstacles.
But after lunch, the kids came out with ice cubes to ride their slide to their heart's content. But it wasn’t there: the sled does not go on the sand! For them, this situation turned the other way, showing the harm of friction.
We observe similar cases in winter, when the boys roll out ice paths and rush along them with a run, covering the distance in a matter of minutes! And then elderly people hobble, slip on the snow-covered rolls and fall, breaking their arms and legs. Here again are illustrative examples, where in the same case both the harm and the benefit of the force of friction coexist.
It is to reduce the friction force that skiers lubricate their skis with special ointments in order to increase speed when moving. Skating rinks, where skaters or figure skaters are engaged, are periodically watered and cleaned - also to reduce friction. And footpaths, on the contrary, are sprinkled with sand or ash so that no one falls on them. Some innovators even came up with the idea of gluing pieces of sandpaper to the soles of winter boots and boots just to increase the friction force.
The same thing happens with the wheels of cars. It's no secret that with the onset of winter, drivers "shoe" their iron horses in special "winter tires". Otherwise, without a useful friction force, the braking distance increases, the car skids when cornering, it drives, and often the driver does not manage well. And how the accident ends, everyone knows for himself.
Something we are all about winter, but about ice, but about falling. But are there other moments in everyday life where you can clearly see how the harm and benefit of the force of friction compete with each other? Of course have! They are everywhere. Even in our room.
Here, for example, is a huge and heavy wardrobe. It stands to itself, as if rooted to the spot, and does not move. And if the force of friction suddenly disappeared, what could happen then? And this hulk would have gone from the lightest push around the room! And it is still unknown if we could manage to dodge it. Good friction force, useful!
But my mother decided to rearrange the furniture. And you need to move this notorious closet to another wall. One, two, take it! Three - four, tensed up! Only everything turns out to be useless: the heavier the object, the stronger the friction force holds on to it. Terrible, nasty force!
Again they compete with each other - the harm and benefit of the force of friction. No competition needed! You just need to know physical laws well and be able to extract practical benefits from this knowledge. Is friction force not needed at the moment? So, it should be reduced: to make the contact surfaces smoother, slippery. For this, someone advises smearing the floor with soap or oil, someone puts a wet rag under the legs of a heavy object. And now - one - two - and you're done! Moved quite easily a sort of colossus from its place.
The force of friction constantly accompanies us throughout life, just like the force of gravity. Somewhere it creates inconvenience for us, but somewhere it is impossible to do without it. But be that as it may, it exists, and our task is to learn how to use physical laws in such a way that our life becomes more convenient and comfortable.
What are the benefits and harms of friction?
Alexandr Mogilen
For example, in weaving, friction also plays an important role: it does not allow the threads to straighten out, and the fabrics to crumble into separate threads. As a result of the action on each other, the warp and weft threads are bent, taking a wave-like shape in the fabric.
There are many examples.
What is rocking negative side…. For example, a perpetual motion machine cannot be created because of the friction force, as wear occurs.
For battleships at their speed, the greatest harm is not at all the resistance of the form, but the banal force of friction of water against the skin. And you can't really do anything with it. Even the best color - the so-called "self-polishing" although it reduces - but not to the full extent, so that it greatly reduces the friction force.
In general, there are many examples and pros and cons.
Denis Sivtsev
Seventh grade. The role of the friction force is very large. For example, thanks to the force of friction, we can walk (that is, we interact with the Earth and push off from it), a car can slow down due to the friction of the wheels on the asphalt. But the force of friction is both useful and harmful. If there is ice on the street, we can screw up and hurt ourselves (since the friction is small). And it is calculated by the formula: F = umg, where u is the coefficient of friction.
Prowling Tiger
The benefit of friction force is the grip of wheels with asphalt, for example; IMHO, the main harm is the inability to create a perpetual motion machine due to friction, which has already been indicated in other respects, but not so much due to wear, but due to the fact that the full mechanical energy is not saved ...
And the formula written above F \u003d umg, where u (generally “mu” is a Latin letter) is the coefficient of friction, is a special case of the sliding friction force, when the normal component of the reaction force of the support N is equal to gravity, i.e. when the body lies ( moves) on a horizontal surface, so the formula for the sliding friction force is: F=uN
vika 123
harm or better to say the disadvantages of this phenomenon:
for example, the force of friction leads to wear of car parts: bearings, tires, etc.
because of it, some human actions become painful, for example, if the fingers rub against the handle of a shovel during some work, then calluses will appear as a protective reaction of the body
I was asked in physics to write the harm and benefit of the friction force, I need a bunch of examples !!! Duck what harm and benefit????/
Pavel M
You don't have to look far for examples. Just take a look. What do you see? Do you see the closet? Here it turns out that he is standing against the wall due to the friction force that holds him by the legs. In general, all prefabricated furniture is held together solely by friction. This is a simple example. Cars drive down the street and turn at intersections, also due to traction, and this is provided by friction. Ice, snow porridge - bad grip- here's an accident for you.
On the other hand, friction dissipates energy, converts it into heat, and contributes to the mechanical wear of materials. In many cases, friction is the enemy and they try to get rid of it by introducing lubricants and other tricks. For example, in the same car, there is oil in the engine just to reduce friction. And bearings are designed to convert sliding friction into rolling friction (which is less).
Friction slows down movement; to overcome friction of all kinds, a huge amount of valuable fuel is consumed. Friction causes wear of rubbing surfaces: soles, car tires, machine parts are erased.
The Nobel Prize winner, Swiss physicist Charles Guillaume said: “Imagine that friction can be completely eliminated, then no body, whether it is the size of a stone block or small, like a grain of sand, will ever rest on one another, everything will slide and roll until will not be on the same level. If there were no friction, the Earth would be without bumps, like a liquid. ”
Harm and benefit Forces of friction
Alien Mind
The harm from the force of friction is enormous - for example, a significant part of the energy in various mechanisms is spent on overcoming the force of friction. Therefore, they try to reduce it with the help of lubricants, bearings and the like. People began to try to reduce the force of friction even in primitive times. Vehicle(carts) using tar, vegetable and animal fats as a lubricant. Later developed Various types bearings (to hell with them) that reduce the friction force to acceptable values.
The benefits of the force of friction are also enormous - it is thanks to the force of rest friction that a person can move forward. Therefore, sometimes they try to increase the friction force - for example, they make the sole of the shoe ribbed, put sand on the ice, car treads are also ribbed, and even with spikes. In general, they pervert as they want.
An essay on the benefits and harms of friction force. thank you in advance))
Irina Sorokina
slippery shoes.
friction forces in the thread.
balance point.
over the planet. Life in such conditions is unlikely to be possible. . .
sug dfsvf
Friction is both our enemy and our ally.
In some cases, the absence of friction threatens with big troubles (for example,
braking of cars occurs only due to the forces of friction arising between
shoes and drum), and in some cases even minimal friction forces
render the most harmful effect(for example, in mechanical watch and thin
scientific instruments). However, to understand the full significance of friction, it is necessary to
turn off and watch for future events.
So, what would the world be like without dry and viscous
friction of all kinds? We will not be able to walk or move in any other way.
way. After all, while walking, the soles of our feet experience friction with the floor, and
without friction we will feel worse than we really are smooth ice in the
slippery shoes.
Not a single item (including us)
cannot stay in one place. After all, everything that lies on the table, floor or
just the earth, is held by the friction of rest. And what will happen? All bodies
will begin to move, trying to reach the lowest point. Almost on earth
it is impossible to create a perfectly horizontal surface, even flat
laboratory tables or machine beds have slopes of thousandths of a degree. But
in a world without friction, bodies will move even on such planes.
It is clear that about transport and in general about
operation of any mechanisms and it is not necessary to speak. brake pads, pulleys and
belts, tires and road - none of this will experience mutual friction, but
which means it won't work. Yes, and the machines themselves will not be - they will get out of them
all bolts and all nuts will be unscrewed, since they are held only thanks to
friction forces in the thread.
Disappear suddenly friction, our houses are in
the blink of an eye will crumble - the mortar will no longer hold the bricks driven in
nails will come out of the boards, because they are held there only by friction! whole
only welded or riveted metal structures will remain.
Without friction, many others will disappear
things we are used to. It will not be possible to knit knots from the ropes - they will
sprawl. All woven fabrics will disperse into separate threads, and the threads
disintegrate into their smallest fibers. Such a fate also awaits
metal and rope nets.
Catastrophic changes await
nature - the very appearance of the Earth will change beyond recognition. Waves generated in
ocean, will never subside, and in the atmosphere constant winds of terrible
forces - after all, there is no friction between the individual layers of water and air, which means nothing
does not prevent them from moving very quickly relative to each other. Rivers will come out
their shores, and their waters will rush from high speed across the plains.
Mountains and hills will begin to crumble into
separate blocks and sand. Trees whose roots stay in the ground only because of
friction, by themselves will begin to uproot and crawl in search of the lowest
points. Yes, a terrible picture will appear before our eyes: mountains, trees, huge
lumps, and the soil itself will crawl, mixing, until they find
balance point.
If the friction force disappears, then our
the planet will become a smooth ball, on which there will be no mountains, no hollows, no rivers,
no oceans - all this will break, flow out, mix up and fall into one heap. A
strong, never abating winds will pick up the dust and carry it
over the planet. Life in such conditions is unlikely to be possible. .
Therefore, one cannot speak of friction as
about a harmful physical phenomenon. Yes, often it is simply vital to reduce
friction to a minimum, but often the maximum possible friction forces are also needed, because
that friction is both an enemy and a friend.
Examples of friction force useful and harmful
User deleted
If there was no friction, we could not walk on the ground (remember how our feet slip on ice), we could not ride a bicycle, car, motorcycle (the wheels would spin in place), we would have nothing to wear (threads in the fabric held together by friction). If there were no friction, all the furniture in the room would be crammed into one corner, plates, cups and saucers would slide off the table, nails and screws would not stick to the wall, not a single thing could be held in hands, etc. etc. To this we can add that if there were no friction, it is not known how the development of civilization on Earth would have gone - after all, our ancestors made fire by friction
Harmful: the friction of grains of sand on the metal inside the bearing, the sliding friction of the skates on the ice should be as small as possible, the friction of mechanisms door lock
shoes rub mazols, ..
the perpetual motion machine is not created because of the force of friction, as wear occurs.
For ships at their speed, the greatest harm is not at all the resistance of the form, but the banal force of friction of water against the skin. And you can't really do anything with it. Even the best color - the so-called "self-polishing" although it reduces - but not to the full extent, so that it greatly reduces the friction force.
Dasha Deryabina
The benefits and harms of friction force
Of course, this is a fantasy, and it is full of lyrical simplifications. Life is a little different. But, in fact, despite the fact that there are obvious disadvantages of the friction force, which create a number of difficulties for us in life, it is obvious that without the existence of friction forces, there would be much more problems. So we need to talk about both the dangers of friction forces and the benefits of all the same friction forces.
Examples of the useful aspects of friction forces include the fact that we can walk on the ground, that our clothes do not fall apart, since the threads in the fabric are held due to the same friction forces that by pouring sand on an icy road, we improve traction in order to avoid accidents.
Well, the harm of the friction force is the problem of displacement big cargo, the problem of wear of rubbing surfaces, as well as the impossibility of creating perpetual motion machine, since due to friction, any movement stops sooner or later, requiring constant external influence.
People have learned to adapt and reduce or increase the forces of friction, depending on the need. These are wheels, and lubrication, and sharpening, and much more. There are many examples, and it is obvious that it is impossible to say unequivocally: friction is good or bad. But it exists, and our task is to learn how to use it for the benefit of man.
We were asked in physics to write a fairy tale about the dangers and benefits of friction ... Explain what kind of fairy tale to write in physics?
Vladimir Lis
Fat from the abdomen and sides will go away in just 3-4 days, if taken regularly ...
Soldatova V. M.
Physics teacher
MBOU " high school No. 19 SUIOP"
Stary Oskol
Theme of the lesson "On the benefits and harms of friction force"
Lesson goals.
Educational: to expand and consolidate students' knowledge about the friction force, types of friction force.
Educational: to form the skills of teamwork in combination with the independence of students, to cultivate curiosity.
Developing: to teach students to apply knowledge in new situation, develop the ability to explain the surrounding phenomena, the skills of working with additional literature.
Equipment: presentation, dynamometer, sheet of paper, sheet of sandpaper, drawing table, multimedia equipment.
During the classes.
The lesson begins with the teacher's story about the types of friction force, about the magnitude and direction of the friction force, about the dependence of the sliding friction force on the type of rubbing surfaces, about the mechanism of the origin of the static friction force.
An excerpt from the fairy tale "Turnip" sounds (insert).
Teacher. Grandfather planted a turnip. A large turnip has grown. Heavy-heavy, it grew in all directions, pressed the ground. That is why her tuber has very close contact with the soil, in all tiny cracks and ledges the earth penetrated.
Grandfather went to pick a turnip. Pull-pull, pull can not. He lacks strength. The turnip rests, clings to the ground with irregularities and protrusions, resists its movement. Adhesion of soil particles with the turnip occurs, it prevents the turnip from moving relative to the ground.
While the grandfather is thinking what's the matter, why not pull out the turnip, we will remember the force of friction.
(work on cards)
Task: designation, units of measure and formula for finding the friction force.
Teacher. The grandfather called the grandmother, the grandmother called for the grandfather, the grandfather for the turnip, they pulled, pulled, they couldn’t pull it out, the firmly thickened, rounded root held in the ground. Gravity pushes him to the ground. No, they can't do it together.
Guys, let's help them with our knowledge gained in physics lessons, answer the questions:
1) What is the force of gravity? force of friction?
2) What are the causes of the friction force?
3) What friction forces do you know?
Let's get back to the story. The grandmother called her granddaughter. Granddaughter for grandmother, grandmother for grandfather, grandfather for turnip, they pull, pull, they can’t pull, total strength, which arises along the contact surface of the turnip with the ground and is called the rest friction force.
Let's help them. To do this, we will conduct a laboratory experiment to determine the dependence of the friction force on the type of rubbing surfaces. To conduct the experiment, you must have a dynamometer, a sheet of paper, a sheet of sandpaper, a wooden ruler.
In the course of the laboratory experiment, we conclude: the sliding friction force depends on the type of rubbing surfaces, if the surface of the turnip was smooth, then the turnip would be pulled out.
Granddaughter called Zhuchka. The bug with four paws rested on the ground. There is also a friction force between the paws and the ground. This power helps the Bug in the same way as grandfather, grandmother and granddaughter. Without this force, they would not be able to rest, they would slide along the ground, slip.
A bug for a granddaughter, a granddaughter for a grandmother, a grandmother for a grandfather, a grandfather for a turnip, they cannot pull, pull, pull.
The turnip moved a little. The magnitude of these small displacements is proportional to the applied force and depends on the properties of the soil itself, and the adhesion of the turnip to the ground leads to an increase in the soil elasticity force. And the emerging force of elasticity of the soil is the static friction force. She does not give any way to pull the turnip. Hence, we conclude that the force of friction also causes harm.
The student reads a poem about the benefits of friction and its dangers.
The bug called the cat. A cat for a bug, a bug for a granddaughter, a granddaughter for a grandmother, a grandmother for a grandfather, a grandfather for a turnip, they pull, pull, they can’t pull, and just a little, but still, the external force turned out to be less than the greatest value.
The force of friction is encountered literally at every step. But do people know why it is needed? What is the harm and benefit of friction force? Let's try to figure it out.
Foreword
Several forces act on terrestrial objects, which are closely interconnected and affect the vital activity of bodies. First of all, it is gravity, elasticity (internal resistance of bodies in response to the displacement of their molecules) and support reactions. But there is also a very important physical quantity called the friction force. It, unlike the force of gravity and elasticity, does not depend on the location of the bodies. When studying it, other laws apply: the coefficient of sliding friction and the reaction force of the support. For example, if you need to move a heavy cabinet, then from the very first minute it will become clear that this is not easy to do. In addition, there are certain interferences when performing this task. What hinders the efforts applied to the cabinet? And this is hindered by nothing more than the force of friction, the principle of which is studied at school. The course of physics for grade 7 talks in detail about this phenomenon.
What is under our feet?
People encounter it very often. The benefit of friction is that we would not even be able to take a step without this physical quantity. It is she who keeps our shoes on the surface where we step. Each of us has walked on very slippery surfaces, for example, on ice, and knows firsthand that it is very difficult. Why is this happening? Before we talk about the harm and benefits of friction force, let's define what it is.
The essence of the concept
The force of friction is the interaction of two bodies that occurs at the point of their contact and prevents their movement relative to each other. There are several types of friction - rest, sliding and rolling.
Causes
The first reason is the constant surface roughness. It is this indicator that affects what kind of friction force will take place. If we are talking about smooth surfaces, such as a metal-plated roof or icy areas, then their roughness is almost invisible, but this does not mean that it is not there - it is present at a microscopic level. In this case, the force of sliding friction will act. But if we talk about a cabinet standing on a carpet, then here the roughness of the two objects will significantly impede mutual movement. The second reason is the electromagnetic molecular repulsion that occurs at the point of contact between objects.
Friction of rest
What happens when we try to move a closet, but we cannot move it even a centimeter. What keeps an object in one place? This is the static friction force. The fact is that the applied efforts are compensated by the dry friction force that occurs between the cabinet and the floor.
Harm and benefit of static friction force
It is the static friction force that does not allow the laces on our shoes to untie on their own, the nail that we have just driven into the wall to fall out, and keeps the closet in place. Without it, it would be impossible for people, animals, or cars to move on the earth's surface. Friction damage is also present. It happens on a fairly global scale, for example, the static friction force can lead to deformation of ship plating.
Scientific rationale
In order to move the cabinet, it is necessary to apply a force to it that will overcome friction. That is, as long as the applied force is less than the friction force, the furniture will remain in place. In addition to these factors, there is also the reaction force of the support, which is directed perpendicular to the plane. It depends on the material from which the floor is made (here, the elastic force is also involved). There is also a coefficient of friction, depending on what the two surfaces that interact with each other consist of. Therefore, the friction force acting on the cabinet is equal to the coefficient of friction, which is multiplied by the reaction force of the support (surface).
Sliding friction
So, to overcome the friction, we asked someone to help us move the closet. What have we discovered? That after we applied a force that exceeded the static friction force, the cabinet not only shifted, but also continued to move in the necessary direction for some time, of course, with our help. And the effort spent was about the same throughout the entire journey. In this case, we were prevented by the sliding friction force directed in the opposite direction from the applied action. It is worth noting that its resistance is much lower than that of the static friction force. To reduce this figure, if necessary, various lubricants are used.
Rolling friction force
If we remember that someday we will have to move the cabinet back, we decide to equip it with wheels. In this case, the resulting interaction will be called rolling friction, since the object will no longer slide, but roll on the surface. The rolling wheels will be pressed into the carpet a little, forming a tubercle that we will need to overcome. This determines the force of rolling friction. Of course, if we roll the cabinet not on the carpet, but, for example, on the parquet, then it will be even easier to move it, due to the fact that the parquet surface is harder than the carpet surface. For the same reason, it is much easier for cyclists to ride on a highway than on a fine sand beach.
Ambiguous question
What is the harm and benefit of any type of friction force? Of course, the examples given are somewhat exaggerated - in life everything is a little more complicated. However, despite the fact that the friction force has obvious disadvantages that create a number of difficulties in life, it is clear that without it there would be much more problems. Therefore, this value has its advantages and disadvantages.
Negative Examples
Among the examples of the harm of this force, one of the first places is the problem of moving heavy loads, the rapid wear of favorite things, and the impossibility of creating a perpetual motion machine, because due to friction, any movement sooner or later stops, requiring third-party intervention.
Positive points
Among the examples of the usefulness of this power is that we can safely walk on the ground without slipping at every step, our clothes are firmly seated and do not instantly become unusable, since the threads of the fabric are held by friction. In addition, people use the principle of this force to sprinkle slippery roads, which avoids many accidents and injuries.
conclusions
Mankind has learned to interact with this physical quantity, increasing and decreasing it depending on the goals set. Our immediate task is to try to use it as efficiently as possible.
The harm and benefits of friction force
Not going - just going
Because it's icy
But it falls great!
Why isn't anyone happy?
Such a naive nursery rhyme at first glance - and how much it contains when you look at it from a physical point of view! After all, it is precisely in it that the system of a contradictory attitude to the notorious force of friction is contained. This constant battle, where two concepts compete with each other - the harm and the benefits of the force of friction, will never have a winner. After all, what is convenient and beneficial for one person is often quite the opposite for another - bad, as in this poem.
Remember the story of Nikolai Nosov about the ice slide that the guys built in the yard? And when they all left for dinner, the one who did not participate in the construction came out. He tried to climb on it, but only hurt himself, but he could not climb. And the kid guessed to sprinkle sand on the ice - it became very convenient to climb to the very top even on ice! So, having increased the force of friction between the slippery ice and the sole with the help of sand, the boy realized that the use of friction allows him to overcome obstacles.
But after lunch, the kids came out with ice cubes to ride their slide to their heart's content. But it wasn’t there: the sled does not go on the sand! For them, this situation turned the other way, showing the harm of friction.
We observe similar cases in winter, when the boys roll out ice paths and rush along them with a run, covering the distance in a matter of minutes! And then elderly people hobble, slip on the snow-covered rolls and fall, breaking their arms and legs. Here again are illustrative examples, where in the same case both the harm and the benefit of the force of friction coexist.
It is to reduce the friction force that skiers lubricate their skis with special ointments in order to increase speed when moving. Skating rinks, where skaters or figure skaters are engaged, are periodically watered and cleaned - also to reduce friction. And footpaths, on the contrary, are sprinkled with sand or ash so that no one falls on them. Some innovators even came up with the idea of gluing pieces of sandpaper to the soles of winter boots and boots just to increase the friction force.
The same thing happens with the wheels of cars. It's no secret that with the onset of winter, drivers "shoe" their iron horses in special "winter tires". Otherwise, without a useful friction force, the braking distance increases, the car skids when cornering, it drives, and often the driver does not manage well. And how the accident ends, everyone knows for himself.
Something we are all about winter, but about ice, but about falling. But are there other moments in everyday life where you can clearly see how the harm and benefit of the force of friction compete with each other? Of course have! They are everywhere. Even in our room.
Here, for example, is a huge and heavy wardrobe. It stands to itself, as if rooted to the spot, and does not move. And if the force of friction suddenly disappeared, what could happen then? And this hulk would have gone from the lightest push around the room! And it is still unknown if we could manage to dodge it. Good friction force, useful!
But my mother decided to rearrange the furniture. And you need to move this notorious closet to another wall. One, two, take it! Three - four, tensed up! Only everything turns out to be useless: the heavier the object, the stronger the friction force holds on to it. Terrible, nasty force!
Again they compete with each other - the harm and benefit of the force of friction. No competition needed! You just need to know physical laws well and be able to extract practical benefits from this knowledge. Is friction force not needed at the moment? So, it should be reduced: to make the contact surfaces smoother, slippery. For this, someone advises smearing the floor with soap or oil, someone puts a wet rag under the legs of a heavy object. And now - one - two - and you're done! Moved quite easily a sort of colossus from its place.
The force of friction constantly accompanies us throughout life, just like the force of gravity. Somewhere it creates inconvenience for us, but somewhere it is impossible to do without it. But be that as it may, it exists, and our task is to learn how to use physical laws in such a way that our life becomes more convenient and comfortable.
What are the benefits and harms of friction?
Alexandr Mogilen
For example, in weaving, friction also plays an important role: it does not allow the threads to straighten out, and the fabrics to crumble into separate threads. As a result of the action on each other, the warp and weft threads are bent, taking a wave-like shape in the fabric.
There are many examples.
What swings on the negative side .... For example, a perpetual motion machine cannot be created because of the friction force, as wear occurs.
For battleships at their speed, the greatest harm is not at all the resistance of the form, but the banal force of friction of water against the skin. And you can't really do anything with it. Even the best color - the so-called "self-polishing" although it reduces - but not to the full extent, so that it greatly reduces the friction force.
In general, there are many examples and pros and cons.
Denis Sivtsev
Seventh grade. The role of the friction force is very large. For example, thanks to the force of friction, we can walk (that is, we interact with the Earth and push off from it), a car can slow down due to the friction of the wheels on the asphalt. But the force of friction is both useful and harmful. If there is ice on the street, we can screw up and hurt ourselves (since the friction is small). And it is calculated by the formula: F = umg, where u is the coefficient of friction.
Prowling Tiger
The benefit of friction force is the grip of wheels with asphalt, for example; IMHO, the main harm is the inability to create a perpetual motion machine due to friction, which has already been indicated in other respects, but not so much due to wear, but due to the fact that the full mechanical energy is not saved ...
And the formula written above F = umg, where u (generally "mu" is a Latin letter) is the coefficient of friction, is a special case of the sliding friction force, when the normal component of the reaction force of the support N is equal to the force of gravity, i.e. when the body lies ( moves) on a horizontal surface, so the formula for the sliding friction force is: F=uN
vika 123
harm or better to say the disadvantages of this phenomenon:
for example, the force of friction leads to wear of car parts: bearings, tires, etc.
because of it, some human actions become painful, for example, if the fingers rub against the handle of a shovel during some work, then calluses will appear as a protective reaction of the body
I was asked in physics to write the harm and benefit of the friction force, I need a bunch of examples !!! Duck what harm and benefit????/
Pavel M
You don't have to look far for examples. Just take a look. What do you see? Do you see the closet? Here it turns out that he is standing against the wall due to the friction force that holds him by the legs. In general, all prefabricated furniture is held together solely by friction. This is a simple example. Cars drive down the street and turn at intersections, also due to traction, and this is provided by friction. Ice, snow porridge - poor grip - that's an accident for you.
On the other hand, friction dissipates energy, converts it into heat, and contributes to the mechanical wear of materials. In many cases, friction is the enemy and they try to get rid of it by introducing lubricants and other tricks. For example, in the same car, there is oil in the engine just to reduce friction. And bearings are designed to convert sliding friction into rolling friction (which is less).
Friction slows down movement; to overcome friction of all kinds, a huge amount of valuable fuel is consumed. Friction causes wear of rubbing surfaces: soles, car tires, machine parts are erased.
The Nobel Prize winner, Swiss physicist Charles Guillaume said: “Imagine that friction can be completely eliminated, then no body, whether it is the size of a stone block or small, like a grain of sand, will ever rest on one another, everything will slide and roll until will not be on the same level. If there were no friction, the Earth would be without bumps, like a liquid. ”
Harm and benefit Forces of friction
Alien Mind
The harm from the force of friction is enormous - for example, a significant part of the energy in various mechanisms is spent on overcoming the force of friction. Therefore, they try to reduce it with the help of lubricants, bearings and the like. People began to try to reduce the force of friction even in the days of primitive vehicles (carts) using tar, vegetable and animal fats as a lubricant. Later, various types of bearings were developed (to hell with them) that reduce the friction force to acceptable values.
The benefits of the force of friction are also enormous - it is thanks to the force of rest friction that a person can move forward. Therefore, sometimes they try to increase the friction force - for example, they make the sole of the shoe ribbed, put sand on the ice, car treads are also ribbed, and even with spikes. In general, they pervert as they want.
An essay on the benefits and harms of friction force. thank you in advance))
Irina Sorokina
slippery shoes.
friction forces in the thread.
balance point.
over the planet. Life in such conditions is unlikely to be possible. . .
sug dfsvf
Friction is both our enemy and our ally.
In some cases, the absence of friction threatens with big troubles (for example,
braking of cars occurs only due to the forces of friction arising between
shoes and drum), and in some cases even minimal friction forces
have the most harmful effect (for example, in mechanical watches and thin
scientific instruments). However, to understand the full significance of friction, it is necessary to
turn off and watch for future events.
So, what would the world be like without dry and viscous
friction of all kinds? We will not be able to walk or move in any other way.
way. After all, while walking, the soles of our feet experience friction with the floor, and
without friction, we will feel worse than on the smoothest ice in the
slippery shoes.
Not a single item (including us)
cannot stay in one place. After all, everything that lies on the table, floor or
just the earth, is held by the friction of rest. And what will happen? All bodies
will begin to move, trying to reach the lowest point. Almost on earth
it is impossible to create a perfectly horizontal surface, even flat
laboratory tables or machine beds have slopes of thousandths of a degree. But
in a world without friction, bodies will move even on such planes.
It is clear that about transport and in general about
operation of any mechanisms and it is not necessary to speak. Brake pads, pulleys and
belts, tires and road - none of this will experience mutual friction, but
which means it won't work. Yes, and the machines themselves will not be - they will get out of them
all bolts and all nuts will be unscrewed, since they are held only thanks to
friction forces in the thread.
Disappear suddenly friction, our houses are in
the blink of an eye will crumble - the mortar will no longer hold the bricks driven in
nails will come out of the boards, because they are held there only by friction! whole
only welded or riveted metal structures will remain.
Without friction, many others will disappear
things we are used to. It will not be possible to knit knots from the ropes - they will
sprawl. All woven fabrics will disperse into separate threads, and the threads
disintegrate into their smallest fibers. Such a fate also awaits
metal and rope nets.
Catastrophic changes await
nature - the very appearance of the Earth will change beyond recognition. Waves generated in
ocean, will never subside, and in the atmosphere constant winds of terrible
forces - after all, there is no friction between the individual layers of water and air, which means nothing
does not prevent them from moving very quickly relative to each other. Rivers will come out
their shores, and their waters will rush with great speed across the plains.
Mountains and hills will begin to crumble into
separate blocks and sand. Trees whose roots stay in the ground only because of
friction, by themselves will begin to uproot and crawl in search of the lowest
points. Yes, a terrible picture will appear before our eyes: mountains, trees, huge
lumps, and the soil itself will crawl, mixing, until they find
balance point.
If the friction force disappears, then our
the planet will become a smooth ball, on which there will be no mountains, no hollows, no rivers,
no oceans - all this will break, flow out, mix up and fall into one heap. A
strong, never abating winds will pick up the dust and carry it
over the planet. Life in such conditions is unlikely to be possible. .
Therefore, one cannot speak of friction as
about a harmful physical phenomenon. Yes, often it is simply vital to reduce
friction to a minimum, but often the maximum possible friction forces are also needed, because
that friction is both an enemy and a friend.
Examples of friction force useful and harmful
User deleted
If there was no friction, we could not walk on the ground (remember how our feet slip on ice), we could not ride a bicycle, car, motorcycle (the wheels would spin in place), we would have nothing to wear (threads in the fabric held together by friction). If there were no friction, all the furniture in the room would be crammed into one corner, plates, cups and saucers would slide off the table, nails and screws would not stick to the wall, not a single thing could be held in hands, etc. etc. To this we can add that if there were no friction, it is not known how the development of civilization on Earth would have gone - after all, our ancestors made fire by friction
Harmful: the friction of sand grains on the metal inside the bearing, the sliding friction of the skates on the ice should be as small as possible, the friction of the door lock mechanisms
shoes rub mazols, ..
the perpetual motion machine is not created because of the force of friction, as wear occurs.
For ships at their speed, the greatest harm is not at all the resistance of the form, but the banal force of friction of water against the skin. And you can't really do anything with it. Even the best color - the so-called "self-polishing" although it reduces - but not to the full extent, so that it greatly reduces the friction force.
Dasha Deryabina
The benefits and harms of friction force
Of course, this is a fantasy, and it is full of lyrical simplifications. Life is a little different. But, in fact, despite the fact that there are obvious disadvantages of the friction force, which create a number of difficulties for us in life, it is obvious that without the existence of friction forces, there would be much more problems. So we need to talk about both the dangers of friction forces and the benefits of all the same friction forces.
Examples of the useful aspects of friction forces include the fact that we can walk on the ground, that our clothes do not fall apart, since the threads in the fabric are held due to the same friction forces that by pouring sand on an icy road, we improve traction in order to avoid accidents.
Well, the harm of the friction force is the problem of moving large loads, the problem of wear of rubbing surfaces, as well as the impossibility of creating a perpetual motion machine, since due to friction any movement stops sooner or later, requiring constant third-party influence.
People have learned to adapt and reduce or increase the forces of friction, depending on the need. These are wheels, and lubrication, and sharpening, and much more. There are many examples, and it is obvious that it is impossible to say unequivocally: friction is good or bad. But it exists, and our task is to learn how to use it for the benefit of man.
We were asked in physics to write a fairy tale about the dangers and benefits of friction ... Explain what kind of fairy tale to write in physics?
Vladimir Lis
Fat from the abdomen and sides will go away in just 3-4 days, if taken regularly ...
Fat from the abdomen and sides will go away in just 3-4 days, if taken regularly ...
Soldatova V. M.
Physics teacher
MBOU "Secondary School No. 19 SUIOP"
Stary Oskol
Theme of the lesson "On the benefits and harms of friction force"
Lesson goals.
Educational: to expand and consolidate students' knowledge about the friction force, types of friction force.
Educational: to form the skills of teamwork in combination with the independence of students, to cultivate curiosity.
Developing: to teach students to apply knowledge in a new situation, to develop the ability to explain the surrounding phenomena, the skills of working with additional literature.
Equipment: presentation, dynamometer, sheet of paper, sheet of sandpaper, drawing table, multimedia equipment.
During the classes.
The lesson begins with the teacher's story about the types of friction force, about the magnitude and direction of the friction force, about the dependence of the sliding friction force on the type of rubbing surfaces, about the mechanism of the origin of the static friction force.
An excerpt from the fairy tale "Turnip" sounds (insert).
Teacher. Grandfather planted a turnip. A large turnip has grown. Heavy-heavy, it grew in all directions, pressed the ground. That is why her tuber had a very tight contact with the soil, the earth penetrated into all the smallest cracks and ledges.
Grandfather went to pick a turnip. Pull-pull, pull can not. He lacks strength. The turnip rests, clings to the ground with irregularities and protrusions, resists its movement. Adhesion of soil particles with the turnip occurs, it prevents the turnip from moving relative to the ground.
While the grandfather is thinking what's the matter, why not pull out the turnip, we will remember the force of friction.
(work on cards)
Task: designation, units of measure and formula for finding the friction force.
Teacher. The grandfather called the grandmother, the grandmother called for the grandfather, the grandfather for the turnip, they pulled, pulled, they couldn’t pull it out, the firmly thickened, rounded root held in the ground. Gravity pushes him to the ground. No, they can't do it together.
Guys, let's help them with our knowledge gained in physics lessons, answer the questions:
1) What is the force of gravity? force of friction?
2) What are the causes of the friction force?
3) What friction forces do you know?
Let's get back to the story. The grandmother called her granddaughter. The granddaughter for the grandmother, the grandmother for the grandfather, the grandfather for the turnip, pull-pull, they cannot pull, the total force that arises on the surface of contact of the turnip with the ground and is called the rest friction force.
Let's help them. To do this, we will conduct a laboratory experiment to determine the dependence of the friction force on the type of rubbing surfaces. To conduct the experiment, you must have a dynamometer, a sheet of paper, a sheet of sandpaper, a wooden ruler.
In the course of the laboratory experiment, we conclude: the sliding friction force depends on the type of rubbing surfaces, if the surface of the turnip was smooth, then the turnip would be pulled out.
Granddaughter called Zhuchka. The bug with four paws rested on the ground. There is also a friction force between the paws and the ground. This power helps the Bug in the same way as grandfather, grandmother and granddaughter. Without this force, they would not be able to rest, they would slide along the ground, slip.
A bug for a granddaughter, a granddaughter for a grandmother, a grandmother for a grandfather, a grandfather for a turnip, they cannot pull, pull, pull.
The turnip moved a little. The magnitude of these small displacements is proportional to the applied force and depends on the properties of the soil itself, and the adhesion of the turnip to the ground leads to an increase in the soil elasticity force. And the emerging force of elasticity of the soil is the static friction force. She does not give any way to pull the turnip. Hence, we conclude that the force of friction also causes harm.
The student reads a poem about the benefits of friction and its dangers.
The bug called the cat. A cat for a bug, a bug for a granddaughter, a granddaughter for a grandmother, a grandmother for a grandfather, a grandfather for a turnip, they pull, pull, they can’t pull, and just a little, but still, the external force turned out to be less than the greatest value.
The benefits and harms of bananas for women
The benefits and harms of pickled cucumbers
Lesson topic:
Friction force. Harm and benefit of friction force. Ways increased And i and reduce the force of friction
Completed:
Sadykova N.S.,
Secondary school No. 12, Kapshagay, s. Zarechnoe
Lesson topic: “The force of friction .Harm and benefit of friction force. Ways to increase and reduce friction»
Lesson Objectives:
Tutorial:
introduce the concept of friction force and acquaint students with its features;
study the causes and types of friction, find out the nature of the friction force, its direction, ways to increase and decrease;
give a qualitative definition of this concept.
Developing:
create conditions for the development of mental and communicative qualities of students;
develop students' creative abilities (writing reports and fairy tales).
Educational:
to cultivate observation, culture of speech, the ability to clearly express one's thoughts;
educate the ability to see the physics around you.
Lesson type: lesson of studying new material, problem-search.
Devices and materials: textbook "Physics and Astronomy 7"; didactic aids (task cards); inclined plane; light trolley; demonstration dynamometer; cargo set.
Lesson plan (45 minutes):
Org. moment (3 minutes)
Updating knowledge (7 minutes).
Explaining new material (20 minutes)
Reflection (10 minutes)
Homework, debriefing (5 minutes).
During the classes:
1. Org. moment(3 minutes).
Hello. Sit down.
Today we are starting to study a new topic "The Force of Friction". In the lesson, we will introduce the concept of friction force and get acquainted with its features, study the causes and types of friction, find out the nature of the friction force, its direction, ways to increase and decrease.
To do this, we will repeat the forces that we have already gone through.
(reference compendium No. 1 "Strength" )
WITH 
ILA,F
Force of gravity, F strand Force of elasticity, F control
2. Actualization of knowledge (7 minutes).
We have already studied the force of gravity and the force of elasticity. Now, in order to once again consolidate the studied forces, you will write a test.
(Test 3 options, hand out)
Option I
I. The weight of a body is the force with which...
II. Gravity is the force with which...
III. The elastic force is the force with which...
1. the body is attracted to the Earth.
2. a body acts on another body causing deformation.
3. the body, due to attraction to the Earth, acts on a support or suspension.
2. What force keeps the satellite in orbit?
Gravity.
Body weight.
Elastic force.
3. By international agreement, the unit of force is accepted ..
newton. The abbreviation is N.
kilogram. The abbreviation is kg.
meter per second. The abbreviation is m/s.
4. What is the force of gravity acting on a body of mass 50 kg?
Option II
1. Choose the right statement
I. The stone falls to the ground due to the fact that it is affected by ...
1.body weight.
2. strength of elasticity.
3. gravity.
2. The spring, under the action of a weight suspended from it, has stretched. What force caused the spring to stretch?
Gravity.
Body weight.
Elastic force.
3. 1 Newton is a force that ...
for 1 s imparts a speed of 1 m / s to a body of mass 1 kg.
for 1 s changes the speed of the body by 1 m / s.
for 1 s changes the speed of a body with a mass of 1 kg by 1 m / s.
4. What is the force of gravity acting on a body of mass 5 kg?
Option III
1. Choose the right one statement
I. The body released from the hands falls to the ground. What force causes bodies to fall?
II. A book lying on a table is affected from the side of the table by…
III. On the table, from the side of the book lying on it, acts ...
1. gravity.
2. strength of elasticity.
3. body weight.
2. Does gravity depend on body mass?
The force of gravity is directly proportional to the mass of the body.
Does not depend.
The greater the mass of the body, the less the force with which it is attracted to the Earth.
3. 1 Newton is approximately equal to the force of gravity acting on a body with a mass ...
4. The body has a mass of 0.5 kg. What is the weight of this body if it is motionless and is on a horizontal support?
3. Explanation of new material (25 minutes).
Epigraph(On the desk):
"Omnipresent, necessary, interfering -
Here it is - friction!
I begin the study of the topic by raising the problem, demonstrating experience.
Experience: I drive a toy car. As time goes by, it stops moving.
Why does the car stop? (listen to student answers)
After this experience, students assume that there is some kind of power.
After that I announce the topic of the lesson and pose the following problem
What is the reason for the existence of friction forces?
(reference abstract No. 2 "Characteristics of the friction force")
Experience: I construct an inclined plane from a plywood board and a bar. I put the cylinder on the inclined plane with the side surface and release it. Place the cylinder upside down on the same inclined plane and release.
Children answer questions:
What caused the cylinder to move in the first experiment?
(Answer: gravity)
What caused the rest of the cylinder in the second experiment?
(Answer: the appearance of a force that compensates for gravity)
Definition
I give a definition new strength:
the force arising from the movement of one body on the surface of another and directed in the direction opposite to the movement is called friction force.
Designation and unit of measure
I show how the force of friction is indicated .
Friction force measuring device
dynamometer
How can friction force be measured?
Experience: We put a wooden block with weights on the plywood plane, hook it with a dynamometer and evenly move it along the plane. The dynamometer shows some force.
Children answer questions:
What force does the dynamometer show?
(Answer: the dynamometer shows a force of 1.5 N)
A force acts on the body, but the speed of movement does not change. This means that there is a compensating force equal to the force of the dynamometer.
Where is the force equal to the driving force directed?
(Answer: the force is directed against the movement of the bar);
Where is the point of application of this force?
(Answer: the point of application is at the point of contact of two surfaces).
Make a conclusion.
measuring the force with which the dynamometer acts on the body when it uniform motion , we find the force of friction.
magnitude and direction
We have already found out from experience that the friction force has a direction, and the force has a direction, then this quantity is vector.
Friction force is a vector quantity.
The force is directed against the movement of the body.
Formula
,
Where 
- coefficient of friction, 
is the force of normal pressure.
Friction coefficient - this is already a calculated value, given in table No. 4 on page 216.
The force of normal pressure is the force with which the body acts on the support, directed perpendicular to the support.
N = F heavy => N = mg
Causes
Experience: To do this, we compare the movement of a metal ball on linoleum, a table, sandpaper and a carpet. Using similar examples, we establish that the cause of friction is surface roughness bodies in contact.
Even the smoothest-looking surfaces have bumps, which prevent the movement of one body on the surface of another. But it turns out that the decrease in irregularities reduces the friction force only at the beginning. A further decrease in roughness leads to an increase in the friction force (I also name the second reason for the appearance of the friction force - molecular interaction, which leads, as it were, to adhesion of the contacting surfaces).
And so, there are two reasons for the occurrence of friction force - surface irregularities And attractive forces between molecules of contacting surfaces.
Surface irregularities
Forces of attraction between molecules of contacting surfaces
With rough surfaces, friction is mainly due to the first cause, and with very smooth surfaces, the molecular nature of friction affects.
Kinds
Friction force
sliding friction rolling friction static friction
If the body slips on the surface, its movement is prevented friction force slip. For example, when we are sledding, we are slowed down by sliding friction
body rolling on the surface prevents rolling friction force. For example, when you ride a bicycle, you are slowed down by rolling friction.
When we try to move the cabinet, acting on it with some force, then if the cabinet remains at rest, we can conclude that the body has not changed its speed. This suggests that there is still a force directed opposite to this action and equal in magnitude to it. This force is called the static friction force. It is the static friction force that prevents heavy objects from moving.
What does the force of friction depend on?
How do you think the friction force will depend on the material of the rubbing surfaces?
From the load?
From the treatment of rubbing surfaces?
And from the area of contact bodies?
So let's do conclusions:
The friction force depends on the material of the contacting bodies, on the load, on the roughness and does not depend on the contact area of the bodies.
Friction, like any physical phenomenon, can be both harmful and beneficial.
When it is useful, they try to increase it. For example, in ice in front of the school, the road is sprinkled with sand.
But when the force of friction interferes, it is reduced. How can friction be reduced?
(I let students express their assumptions. I draw attention to the fact that the friction force can be reduced by changing the reasons on which the friction force depends (roughness, material, load))
But in life it often happens that these causes cannot be eliminated. The only way - change from one kind of friction to another .
Experience: I place a load on the machine turned upside down. I move the trolley evenly over the surface. I note the strength of the dynamometer. Then I put the trolley on wheels and place the same load. With uniform movement, the dynamometer notes less force.
For equal loads, the rolling friction force is always less than the sliding friction force.
To reduce friction, some bodies are carefully ground and lubricated. For example, all parts of mechanisms in cars are carefully ground and covered with a thin layer of lubricant.
4. Reflection (10 minutes).
I summarize the lesson together with the students: have they achieved the goals set at the beginning of their work; did we like the job? To consolidate the studied material and control students' knowledge
1) And now, I suggest you find answers to folk omens and proverbs (didactic aids - cards with proverbs). Determine the value of the friction force for each proverb, and what role this force plays positive or negative (3 minutes).
Mow, scythe, while dew,
Dew down - and you're home.
(Russian)
Things went like clockwork.
(Russian)
From idleness and the shovel rusts.
(Russian)
It will fit into the soul without soap.
(Russian)
From that cart sang
That I haven’t eaten tar for a long time.
(Russian)
No, such a person who at least once did not slip on the ice.
(Ossetian)
What but, and cuts.
(Russian)
An unlubricated wheel will grind the axle.
(Uzbek)
Three, three, three - there will be a hole.
(Russian)
Ant conceived
Move Mount Fuji.
(Japanese)
They don't build on ice.
(Russian)
The shovel is not covered with gold.
(Korean)
An unoiled cart will not go.
(Tajik)
A dry spoon is tearing at your mouth.
(Russian)
From waxed thread
difficult to weave webs.
(Korean)
A woman with a cart is easier for a mare.
(Russian)
The clock may stop
Time is never.
(Serbian)
The plow shines from work.
(Russian)
The key, which is often at work, glistens.
(Turkish)
Saw from work
melted to white.
(Russian)
A rusty plow is cleared only when plowing.
(Mari)
What is round rolls easily.
(Japanese)
The reaping sickle always shines.
Ride like cheese in butter.
(Russian)
Chalk leaves a white trail
and black charcoal.
(Indonesian)
Do not iron against wool.
(Russian)
Oster thorn on a horseshoe,
Yes, it crashes soon.
(Russian)
You can't hold an eel in your hands.
(French)
If you don't, you won't go.
(French)
well rope,
the log house frays. (Japanese)
2) run a test 7 minutes ):
Test
Strength is the cause...
A.… only changes in body speed.
B.... only body deformations.
IN.... changes in the speed and deformation of the body.
G.... body movements.
If a body is at rest or moving uniformly, then...
A.… all forces are directed in one direction.
B.… there are no forces acting on it.
IN.… the forces acting on the body are compensated.
G.... no forces act on it or their resultant is zero.
The force of friction is the force...
A.... with which the Earth attracts bodies to itself.
B.... acting on the body from the side of the deformed support and directed against the deforming force.
IN.... with which the body, due to gravity, acts on a support or suspension.
G.... arising from the movement of one body on the surface of another and directed in the direction opposite to the movement.
The point of application of the friction force is located ...
A.... in the center of the body.
B.... at the point of contact of two bodies.
IN.... at the point of action of an external force.
G.… anywhere in the body.
The force of friction is always directed...
A.…opposite to body movement.
B.…opposite of the deforming force.
IN.... vertically down.
G.… left or right.
The force of friction depends on...
A.… loads.
B.... surface roughness.
IN.... the type of material of the contacting surfaces.
G.… all of the above facts.
Friction can be reduced...
A.…replacing one type of friction with another.
B.…replacing sliding with rolling.
IN.... lubricating friction surfaces.
G.…increasing body speed.
A parachutist, whose mass is 70 kg, descends evenly. What is the air resistance force acting on the skydiver?
A. 350 N.
B. 700 N.
IN. 70 N.
G. None of the answers A-B is correct.
Answers to the test:
The test is done by the students themselves. They exchange their answers among themselves. Answers to test I cook on the board ahead of time. 7 completed tasks - mark “4” (7 points), 8 completed tasks - mark “5” (8 points). There are no marks below. The whole group can discuss the answers to the test questions.
5. Homework, debriefing (3 minutes).
D/Z: §41-42 questions
Reports :
1. Friction and motion (sliding and rolling).
2. Friction and rest.
3. Liquid friction (lubrication).
4. Why does friction occur (causes of friction)?
5. Slide and roll. (A story about bearings; rolling and sliding).
