My research on friction

[Abstract]

In this paper, the types of friction, definition, the magnitude of friction, the calculation method of friction, and the conditions for generating friction are described.

[keyword]

Friction; definition; calculation

【introduction】

In today's world, friction is everywhere. But how much research do you have? The author has done research on this. The following shows the research results of the author.

【Friction】

Definition: Two objects that touch each other when they are about to occur or have relative motion. A force that blocks relative motion is created on the contact surface, and this force is called friction.

There are three conditions that must be generated to create friction between objects:

First, the objects touch and squeeze each other

Second, there is a relative motion trend or relative motion between objects.

Third, the contact surface between objects is rough

[sliding friction]

Definition: The friction generated when an object slides on the surface of another object is called sliding friction. (2) A large number of experiments have shown that the magnitude of the sliding friction is only related to the magnitude of the pressure and the roughness of the contact surface. The greater the pressure, the greater the sliding friction; the rougher the contact surface, the greater the sliding friction.

Sliding friction is the force that hinders the relative motion between objects in contact with each other, not necessarily the force that hinders the movement of the object. That is, the friction is not necessarily the resistance. It may also be the driving force for moving the object. It is necessary to clearly prevent the "relative motion" from being the object of contact with each other. "Object motion" may be based on other objects. For example, in the experiment, a weight is placed on the wooden block, and when the wooden block is used to pull the wooden block for uniform linear motion, the weight is changed from static to moving with the wooden block due to the static friction of the wooden block. The specific situation is: when the wooden block is moved forward by the static force, the weight slides backward relative to the wooden block, and the wooden block gives the weight a frictional force that hinders it from sliding backward. The direction of the friction is forward. . Therefore, the weight does not slide relative to the wood block, and the friction at this time is static friction.

The amount of sliding friction is independent of the speed of the object's motion, regardless of the size of the contact area between the objects.

When studying practical problems, in order to simplify the often "idealized" approach, such as placing an object on the smooth surface of another object, this "smooth" means that if two objects move relative to each other, there is no friction.

[static friction]

Static friction: When an object moves with another object in the tangential direction of the contact surface or has a tendency to move relative to each other, there is a force between the contact faces of the two objects that hinders their relative motion. This force is called friction. If two objects that are in contact with each other and are relatively static, if there is only a relative sliding tendency under the action of external force, and no relative sliding occurs, the force that hinders the relative sliding between the contact surfaces is called "static friction". ".

(2) Conditions for generating static friction:

1 contact surface is rough;

2 two objects are in contact with each other and are pressed against each other;

3 There is a tendency for relative motion between objects.

Direction of static friction:

1 direction: Tangent to the contact surface, and the direction of the opposite movement of the object is opposite. The so-called relative is based on the applied force of the applied force.

2 Determination of the direction of the relative motion trend: assuming that the contact surface is smooth and has no friction, look at the relative motion direction of the object, thereby determining the direction of the relative motion trend

The amount of static friction:

1 Maximum static friction: There is a maximum value of static friction, called maximum static friction. It is equal to the minimum external force required to make an object just move.

2 The magnitude of the static friction is not a fixed value, and the static friction varies with the actual situation, and the size is between zero and the maximum static friction force Fm. Its value can be determined by the motion state of the object.

Static friction is very common. For example, the bottle and brush in the hand will not slip, which is the result of static friction. It is also possible to sew the thread into a cloth and sew the cloth into clothes, which is also a function of static friction between the yarns. Static friction is also used in production technology. For example, a belt conveyor transports goods to other places by static friction between the cargo and the conveyor belt.