What is friction? What is the meaning of this physical quantity? There are many interesting physical phenomena in the surrounding world: lightning, snow, hail, thunder. What is friction? Let's analyze the features of this process, its scope.
Examples of occurrence
If you scatter, you can ride along the icy path for a certain length. On an asph alt surface, this situation is impossible. What is the reason for this difference? Friction determines this difference. Physics considers in detail all the causes of this force.
Characteristic
The force of friction of motion occurs when two bodies come into contact. One of them will prevent the movement of the second, this force is the force of friction. There are several variants of such forces that arise under certain conditions.
Varieties of friction
If it is necessary to move a heavy cabinet, it is rather problematic for one person to do it. It is necessary to increase the "shearing" force. In this case, the static friction force will also increase. Its direction is opposite to the movement of the sliding cabinet.
At the moment when the traction force acquires a value greater than the static friction, the cabinet changesyour location. At this point, another friction force appears. The acceleration possessed by the friction of movement determines the nature of the movement. If it prevails over the traction force, then it will be difficult to talk about fast movement.
Sometimes there are situations on highways in which several people try to move a stalled vehicle. While pushing the car, they use the force of rolling friction. During the rolling of the body on the road surface, acceleration occurs.
The friction coefficient in this case depends on the pattern on the tires, the condition of the roadway, weather conditions.
If a round ball moves along the surface, the friction is negligible. This phenomenon is widely used in everyday life. Massive furniture is equipped with special wheels, allowing (if necessary) to move it from one part of the room to another.
Power features
What is friction? This is a force directed opposite to the movement of the body. This physical quantity contributes to a decrease in the speed of the body. If it were not for this force, it would be possible to move on roller skates or a bicycle without making any effort for this. It is the existence of the friction force that explains the movement of the vehicle for a certain distance after the engine has been turned off. The main types of friction are: rolling, sliding, rest.
The nature of friction
Thinking aboutwhat friction is, it is necessary to reveal the nature of the occurrence of this force. In the presence of a smooth surface, such as ice or a polished table, minor roughness can only be seen with a magnifying glass or microscope. It is for them that the body moving along the surface will “cling”. Since the moving object itself has certain irregularities, there is contact between the surfaces.
At first, the bodies are attracted to each other, but as the moving object moves away, the adhesion is destroyed. As a result, there is a vibration of atoms, freed from mutual attraction. The state of a stretched spring can be described similarly.
When rubbing, there is an increase in temperature, that is, a certain amount of heat is released.
Causes of friction
This force arises when there are irregularities on the contact surface of two bodies, and also due to the force of intermolecular interaction.
The force of friction depends on the material from which the contacting surfaces are made, the weight of the interacting objects. For the mathematical calculation of this physical quantity, there is a special formula that relates the friction force to the force acting on the support, as well as to the coefficient of friction.
It reflects the dependence of the desired force on the selected material, as well as on the quality of its processing. The unit of support reaction when moving a body on a horizontal surface is equal to its weight. In the case of an inclined plane, its value decreases, therefore, from a steep mountainon skis (sleds) you can ride a very impressive distance.
This force does a certain amount of work. If the body moves, work must be done. The force of friction tries to prevent the movement of an object on a surface. That is why the work she does has a negative value.
Apply friction
A person in his daily life is always accompanied by the force of friction. It can have both positive and negative effects. For example, if there were no such force in nature, the bodies would slide down, the transport would fall apart into separate parts.
It would be difficult to tie shoelaces, to keep interior items in a permanent place. A person in the absence of friction would not be able to take even one step. In order to solve this problem, during heavy ice they try to sprinkle the tracks with a thick layer of sand. By increasing the roughness of the surface, the friction force is also increased, helping people to move smoothly on slippery sections of the road or sidewalk.
But in addition to the positive effect, friction often exhibits negative properties. People know how to increase and decrease its value, getting the maximum benefit for themselves. For example, in order to move a heavy load from one place to another, wheels are used. In order to turn sliding into rolling, for example, increase the surface roughness.
Depending on what pattern was applied to the tires, they are used to move the vehicle on different sections of the road.
Rubber is black because it contains coal. It is necessary to give the tires strength, the necessary rigidity, and increase friction on the road surface. With the correct calculation of the friction force, you can get the desired result.
