On the question of what factors are related to the magnitude of friction

In some cases, the amount of friction is related to the velocity.

In curvilinear motion (bicycle turning, for example), according to f=mv 2r(f denotes the centripetal force, where the centripetal force is a component of the frictional force.) v represents the linear velocity at this time, which is the instantaneous rate v at this time', r represents the radius of the curve motion) It is concluded that when the turning speed is larger, the required centripetal force will be greater, and part of the centripetal force of the car turning is provided by the friction between the car and the road surface, that is to say, the centripetal force at this time is partly a component of the frictional force, (here you will ask what provides the other centripetal force?).

When the bicycle turns, the car will tilt to one side, and the support force on the ground is no longer in the same straight line as the car's gravity. The support force provides another part of the centripetal force, digression, hehe) So when the speed of the vehicle is reasonable and the friction can provide this part of the centripetal force at this time, the friction force will be provided according to the magnitude of the speed.

The magnitude of friction is also related to the material of the contact surface of the object.

Well, it's finally done for you. It's late, it's almost 12 o'clock. Sleepy.

In fact, it has nothing to do with velocity, but it is also related to the material of the object.

It's like there's gone, and the coefficient of friction seems to be determined by the roughness, and then there's the contact pressure.

But it seems to have nothing to do with the speed of the object!

There are two types of friction:

Static friction: The object is not moving. The magnitude is equal to the net force of the remaining forces in the same direction.

Sliding friction: The motion of an object. The magnitude is equal to the product of the dynamic friction factor and the positive pressure subjected, where the dynamic friction factor is related to the roughness of the contact surface, and the rougher it is, the greater the dynamic friction factor. Nothing to do with speed.

Experiment to study what factors are related to the magnitude of sliding friction: Why do you use a spring scale to pull a wooden block to do a uniform linear motion during the experiment? This is because the spring scale measures the amount of tension and not the amount of friction.

When the wooden block moves in a uniform linear motion, the tensile force in the horizontal direction of the wooden block and the frictional force of the wooden board on the wooden block are a pair of balancing forces. According to the condition of the balance of the two forces, the magnitude of the pulling force should be equal to the magnitude of the friction force. Therefore, the magnitude of the tensile force is measured, that is, the magnitude of the friction force is measured.

A large number of experiments have shown that the magnitude of sliding friction is only related to the amount of 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.

Hehe! Brother, why are you drilling the horns! Your idea is good!

But there are things you don't need to know too much! When you go to college and graduate school in the future, you are coming to ** these questions! Don't be too stubborn.

In fact, the amount of friction is not only related to the material of the contact surface of the object. It is also related to the state of motion seen by the object. It also has to do with the humidity!

Don't talk too much! You mainly figure out what the magnitude of static friction and sliding friction is related to! In fact, figuring out these is what will help you analyze the force on an object!

In this way, the relationship between the state of motion of the object and the external forces experienced by the object can be solved.

The state of motion of the object, the degree of humidity.

That's all. Maybe there are some scientists who haven't found out.

There are two factors that affect the magnitude of friction:

1. The magnitude of friction is related to the pressure between the contact surfaces, and when the roughness of the contact surface is constant, the greater the pressure, the greater the friction.

2. The magnitude of friction is related to the roughness of the contact surface, when the pressure is constant, the rougher the contact surface, the greater the friction.

The friction between solid surfaces is divided into sliding friction, rolling friction, static friction, rolling 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 occur if the liquid is not completely isolated.

The air cushion guide rail uses gas friction to work, and the working principle of both lubricating oil and air cushion guide rail uses "friction with liquid or gas (i.e. fluid) instead of solid friction" to work.

Chapter 7 Motion and ForceSection 6 "What is the magnitude of friction related to the student's experiment".

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

1.Contact Surface RoughnessThe greater the roughness of the contact surface, the greater the friction between objects.

2.Pressure at the contact surface: The greater the pressure at the contact surface, the greater the friction.

3.Whether it is rolling friction, static friction or sliding friction: Sliding friction and static friction are higher than rolling differences, and dynamic friction produces more friction.

When two objects in contact with each other are in relative motion or have a tendency to move relatively, a force that hinders the relative motion or tendency to move on the contact surface is called friction. The direction of frictional force is opposite to the direction of the relative motion (or relative tendency of motion) of the object. There are three types of friction: static friction, rolling friction, and sliding friction.

The factors that affect friction are complex, and there are several aspects:

1.Smoothness of the surface of the sliding object: The surface of the object that looks smooth to the naked eye is rough when viewed with a microscopic stocking.

2.Smoothness of the support surface: The support surface cannot be completely smooth and smooth, and there is a certain roughness. This roughness rubs against the uneven fit of the sliding object.

3.Positive Pressure: The force in the normal direction will increase the interaction between the surfaces, thus increasing the frictional force. The frictional force is proportional to the applied normal force [f = n, where is the coefficient of friction].

4.Object Shape: Friction is also present in liquids and gases. Compared to sliding on a solid surface, air or water provides less friction (the higher the speed, the greater the friction). Choosing a streamlined shape can help reduce friction.

5.Contact area: Coulomb's law of friction f = n There is no effect of area, this is an approximate model, and a more accurate model, the pressure area must be taken into account.

6.Friction Type: Rolling friction is always less than sliding friction.

Wheel rolling greatly reduces apparent friction, such as roller skates. In general, the larger the rolling wheel, the smaller the equivalent coefficient of friction and therefore the less effort it takes. So when riding a bicycle, try to choose a model with large wheels if possible.

7.Sliding state: From an engineering point of view (not sci-fi), friction can only be reduced, not eliminated.

Friction can be reduced by forming a liquid lubricant lubrication film on contact surfaces, such as mechanical parts, and we use lubrication methods to avoid friction during operation. Lubricated wet friction is usually less than dry friction. Fluid friction is the friction between an object and a fluid (liquid or gas).

The fluid is not shear resistant, so it glides easily, but it is able to stretch the contact surface apart.