Whether the sliding friction force varies with the magnitude of the tensile force

I think that the conditions provided by the title are wrong, use 2N to pull a wooden block to move in a uniform linear motion, and under the condition that other conditions remain unchanged, the tensile force is from 2N to 3N, and the object can no longer move in a uniform linear motion, but to do accelerated motion.

Sliding friction is only related to the positive pressure and the coefficient of friction (i.e. f = is the positive pressure, which is the coefficient of dynamic friction). It is not directly related to the horizontal tensile force, and under the condition that other conditions remain unchanged, the tensile force is from 2n to 3n, and the positive pressure and friction coefficient remain unchanged, so the sliding friction force remains unchanged.

It is impossible to use 2 N tension to make it uniform and 3 N to make it uniform under the premise that the conditions remain the same.

Static friction is related to tensile force, and sliding friction is only related to the roughness of the contact surface and the mass of the object. (Remember that you will learn later). As for the uniform linear motion you said, it is because the object is balanced by force, so the tensile force is equal to the frictional force, when the object is moving at an uneven speed, (that is, when there is acceleration), the tensile force is not equal to the frictional force, to use Newton's second law f = ma, a is the acceleration, m is the mass, f is the resultant force of the object in the direction of motion, if the object is not moving at a uniform speed, the tensile force minus the sliding friction force is not equal to 0, but ma, it cannot be balanced by force.

It's good to remember if you really don't understand, it's the most basic thing, and I will learn it again in high school.

The friction of the slide will increase more and more.

FrictionThe larger it is, the less likely it is to slip.

The friction between the surfaces of solid tung lead is divided into sliding friction, rolling friction and static friction.

Widening stove pressure friction and rotational friction. In engineering, lubricants are used to reduce friction.

If two surfaces rubbing against each other are separated by a layer of liquid, then liquid friction can occur between them, and mixed friction can also occur if the liquid is not completely isolated. Air cushion rails work by using gas friction.

Introduction to friction.

The surfaces of the objects are uneven, ancient Egypt.

The craftsmen worked hard to polish the huge stones of the pyramids so smoothly that it is said that the stones fit so tightly that not even a blade can fit in, but the huge stones are still not so smooth, and there are many bumps and pits on the surface.

It was a huge task to transport these boulders, which could weigh tons or even more than 160 tons, from the quarry to the site where the pyramids were built.

If we zoom in on the contact surfaces of the objects, we can find that the surface that we thought was flat is actually potholed, and when two uneven objects are close to each other, these uneven surfaces will bite each other, thus increasing the resistance to sliding.

1. The amount of pressure on the object. The greater the pressure on the contact surface, the greater the sliding friction.

2. The roughness of the surface in contact with the object (roughness of the contact surface). The rougher the contact surface, the greater the sliding friction when the pressure on the object is the same.

Factors influencing the magnitude of sliding friction - junior high school physics easy learning to share a set of interesting teaching courses, which is more fun, including all junior high school physics knowledge points, synchronous course explanation, and after-class exercises. Like friends like, favorite,**. Follow me and continue to share quality teaching every day**.

Pressure on the contact surface.

The magnitude of sliding friction is related to the following factors:

Contact area: The larger the contact area, the greater the friction.

Roughness of the surface of the object: The rougher the surface of the object, the greater the friction.

The magnitude of the force exerted on the object: When the force exerted on the object increases, the frictional force also increases.

Pressure between objects: When the pressure between two objects increases, the friction also increases.

It should be noted that the magnitude of sliding friction is generally smaller than that of static friction. This is because when the body is at rest, the tiny uneven parts between the surfaces of the object can be embedded in each other, forming more contact points, thus increasing the contact area, making the static friction greater than the sliding friction.

To solve the problem of friction, you have to understand the concept of friction, i.e., the conditions under which friction is generated.

The so-called friction force is the force that hinders the relative motion of an object, and the direction of friction is opposite to the direction of motion or relative motion of the object.

The conditions for friction to arise are: (1) two objects must be in contact; (2) there is extrusion between the two objects; (3) There is a tendency of motion or relative motion between two objects.

1. An object is stationary on a horizontal plane, and if it is not affected by push or pull, it is not affected by friction. If a push or pull force is received, it belongs to the category of static friction, and the magnitude of the frictional force is equal to the magnitude of the pull or thrust force, and has nothing to do with the gravity or pressure of the object. Only the maximum static friction is related to the pressure or gravity of the object.

2. If the object is pressed against the wall, the magnitude of the frictional force is equal to the gravitational force experienced by the object.

3. As long as the object moves in a uniform linear motion on the horizontal plane, the object is affected by the equilibrium force in the horizontal direction, that is, the thrust or pull force is equal to the friction force.

4. If the object is not pushed by a force of 10n, the object is subjected to static friction, and its magnitude is equal to the magnitude of the thrust. If the force of 15N is just propelled, the friction force experienced by the object is the maximum static friction force, and if the thrust is increased in the future, the friction force will not change. Theoretically, the sliding friction of an object is less than the maximum static friction, but they are generally considered to be equal.

5. If the object with a weight of 10N is pulled with a force of 15N and moves vertically upwards at a uniform speed, the friction force is f=15-10=5N

If you understand what I said above, I think your understanding of friction will be even better!

The magnitude of sliding friction is related to the contact state, surface material, lubrication degree, contact area and movement speed between the objects.

When two objects slide relative to each other (or have a tendency to slide relative to each other), a force that prevents the object from sliding will arise between the contacts, and this force is called sliding friction, or friction for short. The frictional force acts on the contact surface of the object in the opposite direction to the direction of the slide (or the direction relative to the sliding trend).

According to whether there is relative motion between the contact surfaces, sliding friction can be divided into two categories: static sliding friction and dynamic sliding friction.

Expand your knowledge:

1. Definition of sliding friction

Sliding friction refers to the force that hinders the movement of the spike due to the contact between two objects in the process of relative motion. Its magnitude is related to the coefficient of friction and vertical pressure between the objects.

2. The contact state between objects affects the friction force

The state of contact between objects is also a factor that affects the magnitude of sliding friction. If it is in complete contact, the molecular force between its surfaces can be completely transmitted, and the sliding friction is larger. In the case of local contact, some parts are not actually in contact and the molecular force cannot be transmitted, and the sliding friction is relatively small.

3. The influence of surface material and lubrication degree on friction

The surface material also has a great influence on the sliding friction. The contact area between objects with a smooth surface is smaller, whereas the contact area between objects with a rough surface is larger. The degree of lubrication also affects the magnitude of sliding friction, and the use of lubricants can reduce the intermolecular adsorption between surfaces in contact with each other, thereby reducing the coefficient of friction.

4. The influence of contact area and movement speed on sliding friction

The contact area and the speed of movement are also important factors affecting the magnitude of sliding friction. When the contact area between two objects increases, the difficulty of contact between molecules increases, and the friction coefficient also increases. The faster the movement speed, the greater the friction force, because increasing the movement speed will exacerbate the microscopic deformation of the friction surface, resulting in greater contact stress on the surface.

In general, the magnitude of sliding friction is affected by a combination of factors. Proper use of these factors can reduce sliding friction, increase machine efficiency and extend machine life.