What is the work of overcoming friction, and how to understand the work of overcoming friction

The work done to overcome friction is the negative work done by friction. The force acts on a moving object, if the force does not decompose the projection in the direction of motion, it does not do work, if there is a projection direction that is consistent, it does positive work, and if there is a projection direction that is opposite, it does negative work. And the frictional force is opposite to the direction of relative motion, so the frictional force is to do negative work, and it can also be said that the moving object overcomes the frictional force to do work.

Overcoming gravity to do work means that the moving object has an upward displacement in the vertical direction, which is called overcoming gravity to do work. Judge whether the ball has the force to do work on it when rolling on the ground, and analyze the force on the ball, and the ball is subjected to gravity, the support force of the ground, and the friction force at this time. If the ball is moving horizontally, the gravitational and supporting forces are perpendicular to the direction of motion and do no work, only friction does work.

Am I clear enough?

When the force has a component in the direction of motion of the object or in the opposite direction, the force does work on the object. Among them, the same direction is positive work, and the reverse direction is negative work. And to overcome what force is done is that this force does negative work.

In terms of friction, if an object is moving on a horizontal plane and the plane is not smooth, then friction will be generated when it is moving, and negative work will be done. If on the conveyor belt, the object is advanced by the friction between the object and the conveyor belt, the friction at this time is doing positive work. Therefore, it is best to analyze the force on the object and look at the direction of the force.

The work done to overcome friction is the negative work done by friction on the object in its trajectory.

Let's say you're going up the stairs.

If the plank is placed horizontally, the trolley will be subjected to the friction of the plank on it when it moves, and the horizontal direction is not only subject to the rope pull force (the rope pull force can be approximated as equal to the weight gravity), therefore, one end of the plank is raised, so that one component of gravity along the plank can just balance the friction force, so that the trolley can be approximated to be only affected by the tensile force.

When an object slides on the surface of another object, friction occurs between the contact surfaces that hinders their relative motion, which is called sliding friction. The magnitude of sliding friction is related to the magnitude of the roughness of the contact surface and the magnitude of the pressure. The greater the pressure, the rougher the contact surface of the object, and the greater the sliding friction generated.

The methods of increasing the favorable friction are: increasing the pressure, increasing the roughness of the contact surface, and the magnitude of the pressure.

The conditions for the production of friction and aber: first: contact; Second: rough contact surface; Third: there is a force to mess with the locust; Fourth: there is a relative movement or a tendency to relative movement.

The above four conditions are indispensable.

Work is: the product of the force and the distance of the object in the direction of the force.

If the direction of velocity (pulling direction) of the object's motion is the specified direction, then the direction of friction is opposite, and the work done by friction is negative. This means that work is done to overcome friction.

Causes of friction: At present, the causes of friction are not scientifically determined. The cause of friction has always been the subject of scientific exploration, and various scientific hypotheses have been proposed

The bumpiness theory of friction, the adhesion theory of friction, the new frictional adhesion theory, etc. (Note: Friction is a very common force.)

Mo Da early filial piety friction force is a kind of contact force);

Note] At present, the earlier friction of the uneven and uneven is still used, which is to the effect that the surface in contact with the object is rough and uneven, and some objects look smooth to the human eye, but in fact they are not flat, and when the object is in relative motion or has a relative movement trend, the uneven part will hinder it.

I hope it helps you, and if you have any questions, you can ask them

I wish you progress in your studies and go to the next level! (*

First of all, friction is the force that hinders the movement of an object, and the work done to overcome friction is (the original tensile force f - friction force f)s

Overcoming friction is like overcoming gravity.

The direction of gravity is vertically downward, and people climb stairs and go upstairs, then the force f of human movement in the upward process is greater than gravity g, so f-g is the gravity to overcome, and it is also a reason to overcome friction, the force of the original motion of the object is greater than the friction force of the negative work done in motion.

Halo, that is, the work done by the bicycle on the floor when it moves = the work done by him (he overcomes the friction of the bicycle on the floor), is fs=w

Overcoming friction is the work done by friction, the work done by friction is negative, and overcoming friction is positive.

Friction is the force between the ground and the bicycle that hinders the relative motion of the bicycle.

When an object moves on a frictional surface, it is affected by frictional force, and the force experienced by the object at this time is equal to or greater than the frictional force, and how much work is done by the applied force at this time, it can be said how much work has been done to overcome the frictional force.

When the force is less than the frictional force, the object has no displacement and therefore no work has been done.

Friction to do work:

When this term is introduced, it is generally used to indicate that friction is a useful work of arguing bridges. Take conveyor belts, for example.

, friction is the driving force, and the conveyor belt is the static friction force.

Do the right work. The relationship between the two:

When the force in front of the friction gear obstructs the movement of the object, that is, when the negative work is done, the object has to overcome the friction force, and heat will be generated.

Part of the power comes from the applicator, and part of the power generated by the force is turned into kinetic energy, and part of it is turned into heat. The work done by an object to overcome friction is the total work, which is the combination of kinetic energy and heat.

Work done over resistance = Negative work done on the object by resistance.

The essence is still electromagnetic interaction.

Examples of Friction Reduction:

1. Add lubricating oil to the self-tracking scale driving axle, and the air transportation is to reduce friction by separating the contact surfaces from each other.

2. There are wheels under the suitcase, which is convenient and labor-saving to drag and walk, which is to reduce the sliding friction to rolling friction.

4. The fan shaft should be made very smooth, which can reduce friction.

5. Before skating, shave the ice blade, and reduce the friction by reducing the roughness of the contact surface under the same pressure.

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!