When is friction converted into internal energy and when is it converted into kinetic energy?

As long as there is friction to do work, there are other forms of energy that are converted into internal energy, such as kinetic energy being converted into internal energy; When friction does positive work on an object, the kinetic energy of the object increases! Pay attention: which forces are doing work, whether these forces are doing positive work or negative work, the kinetic energy of the object in the initial state, the kinetic energy of the object in the final state, as long as these are sorted out, the energy part will be passed, oh, by the way, the kinetic energy theorem is suitable for the transformation of kinetic energy when all forces do work on the object, where the mechanical energy can be balanced, the kinetic energy theorem can be used!

If the work is done by static friction, only the transfer of energy is involved, not mechanical energy.

and the conversion of internal energy, if it is sliding friction.

The internal energy converted into work is equal to the product of the sliding friction force and the relative displacement of the two objects.

The distinction between these two energy conversions is mainly judged by appearances: the conversion of friction into internal energy is usually accompanied by an increase in temperature, that is, the so-called frictional heat generation; The conversion of friction into kinetic energy is usually accompanied by a change in velocity, i.e., the work done by friction causes a change in kinetic energy.

The sliding friction is all converted into internal energy, and the rolling friction is converted into kinetic energy.

With relative motion, sliding friction must be converted into internal energy.

There are many ways to convert kinetic energy, static friction, sliding friction can be, only sliding friction is accompanied by the generation of internal energy.

As long as the friction is worked, it will be converted into internal energy and kinetic energy

When applying the kinetic energy theorem, when the frictional force is doing work, then it should be subtracted.

The frictional force is opposite to the direction of motion, so it is the negative work done, and this part of the work will be converted into internal energy, which will lead to a decrease in the kinetic energy of the system.

The so-called kinetic energy, simply put, refers to the energy possessed by the motion of an object. Numerically equal to (1 2) mv, after the frictional force is done, according to the theorem of conservation of energy, if one form of energy increases, then another form of energy decreases.

Just answer what you add: the kinetic energy increment of the object is equal to the work done by the combined external force, moving on an inclined plane, the object is subjected to two forces, friction and gravity, and both forces do work, so the kinetic energy increment is the result of the joint action of these two forces.

In addition, the internal energy of transformation is equal to.

The frictional force is multiplied by the relative displacement of the object and the conveyor belt.

In this problem, the energy that the system converts into internal energy, that is, the work done by friction, is the result of multiplying the distance between the block and the conveyor belt by the frictional force.

Because friction does not only work on the block, but also on the conveyor belt.

So to relative the distance of the slide.

According to the law of kinetic energy (the amount of work done by an external force is equal to the amount of change in kinetic energy), the increment of kinetic energy of a block (i.e., the amount of change in kinetic energy) is equal to the work done by an external force (i.e., friction) on the block, so the increment of kinetic energy of a block is equal to the displacement of the block relative to the ground multiplied by the frictional force.

One is the distance the block slides relative to the conveyor belt multiplied by the friction, and the other is the displacement of the block relative to the ground multiplied by the friction.

Of course not.

In addition, the energy converted into internal energy by the system is the sum of the work done by friction on the block and the conveyor belt, and the kinetic energy increment is the work done by friction on the block.

So it's different.

Hope it helps.

Mechanical energy conversion occurs between kinetic energy and potential energy, both gravitational potential energy and elastic potential energy. If there is no other force doing work, then mechanical energy is conserved; When work is done by friction (part of the mechanical energy is converted into internal energy), the mechanical energy is of course not conserved.

Examine the following figures:

Upper left: Objects that do oblique throwing motion (including flat throwing, upward throwing, downward throwing, and free fall motion), regardless of air resistance, the mechanical energy of the object is conserved during motion.

Top right: The object slides down a smooth slope with conserved mechanical energy. Because the supporting force of the inclined plane does not do work, only gravity does the work.

Bottom left: Conservation of mechanical energy of a small ball. Because only gravity and the elastic force of the spring move on the ball.

Bottom right: The mechanical energy of a parachute is not conserved. Because the parachute is dragged by the air during the fall, part of the mechanical energy is converted into internal energy.

Note: Mechanical energy includes kinetic energy and potential energy, and during the conversion process, mechanical energy is equal to the sum of kinetic energy and potential energy. Namely.

e = e momentum + e potential.

If no other force does work to increase or decrease the sum of the mechanical energy of the object, then the mechanical energy is conserved (δe=0).

If the frictional workmanship is all converted into internal energy, the gravitational potential energy is conserved without change.

Summary. The conversion process is that kinetic energy generates heat through friction, and heat is the increase in the temperature of the object and becomes internal energy.

Kinetic energy is converted into internal energy and friction is used to do the work process, how the object moves.

The conversion process is that kinetic energy generates heat through friction, and heat is the increase in the temperature of the object and becomes internal energy.

I would like to ask, the kinetic energy of an object is converted into internal energy, so what energy is there that makes an object move.

Kinetic energy is converted into internal energy, and the friction between two mutual objects and the internal energy produced by the object is the internal energy common to the system. Otherwise, who can it be given to inside.

What about the energy of the object's motion.

The energy of the motion of an object is because of the energy possessed by motion.

The internal energy converted from kinetic energy during the motion of the object, why can the object still move.

The faster the energy and mass, the faster the speed, the higher the ability of the moving object.

Of course, there are also downward forces, frictional forces, gravity forces, and so on.

In the process of converting one's kinetic energy into potential energy, only when there is an external force to do work on it, can it maintain a constant velocity.

Kinetic energy is inseparable from the chosen inertial frame of reference. Potential energy is inseparable from the force field. The interacting force is inseparable from the two objects that interact with each other.

When the direction of friction is consistent with the direction of the movement of the walking ants, friction is the driving force, for example:

1. Walking: When people are walking, friction is the driving force, people want to go forward, shoes have backward friction relative to the ground, and the friction of the ground to the shoes is forward, so people can move forward;

2. Driving: When the car is moving, the tires of the car have a backward movement trend, and the ground gives the tires forward friction, so the friction is the power, but the car is not only a power force when it is moving, but also the power provided by the power device of the car to the car;

3. Conveyor belt: When transporting goods, the industrial conveyor belt only needs to turn on the power supply, and the items can be put on the conveyor belt to move forward, and the friction force is also used here, when the item just touches the conveyor belt, because the conveyor belt is moving forward again, and the item has no speed, so there is a backward movement trend, so the conveyor belt provides the vertical friction of the inlay.

When the direction of friction coincides with the direction of motion, friction is dynamic, for example:

1. Walking: When people are walking, friction is the driving force, people want to go forward, shoes have backward friction relative to the ground, and the friction of the ground to the shoes is forward, so people can move forward;

2. Driving: When the car is moving, the tires of the car have a tendency to move backwards, and the ground gives the tires forward friction, so the friction is the power, but the car is not only friction when it is in motion, but also the power device of the car to provide the wild scum power provided by the car;

3. Conveyor belt: When transporting goods, the industrial conveyor belt only needs to turn on the power supply, and the item can move forward when it is put on the conveyor belt, and the friction force is also used here.

The work done by friction is all converted into internal energy, which is equal to the sliding friction force multiplied by the relative displacement. If there is static friction between two objects, then the sum of the work done by the two static friction forces must be zero, so the static friction force cannot produce heat.

When two objects that are in contact with each other and squeezed each other, when they are in relative motion or have a relative tendency to motion, a force is generated on the contact surface that hinders the relative motion or relative tendency of motion, and this force is called friction.

The direction of frictional force is opposite to the direction of the relative motion of the object or the relative tendency of motion.

There are two causes of friction between solid surfaces: the mutual attraction of atoms and molecules on the solid surface (energy requirements for chemical bond recombination, glue force) and the resistance to each other caused by the roughness of the surface between them.

Internal energy, from a microscopic point of view, is the statistical average of the sum of the energies moving irregularly. The energy of the irregular motion of a molecule includes the kinetic energy of the molecule, the potential energy of the interaction between the molecules, and the energy of the internal motion of the molecule. The internal energy of an object does not include the kinetic energy of this object when it is in motion as a whole and its potential energy in the gravitational field.

In principle, the internal energy of an object should include the sum of the kinetic energy, potential energy, chemical energy, ionization energy and nuclear energy inside the nucleus of all microscopic particles, but in the process of changing the general thermodynamic state, the molecular structure, atomic structure and nuclear structure of the substance do not change, so the change of these energies can not be considered. But when chemical reactions are involved in thermodynamics research, chemical energy needs to be included in the internal energy.

You may not understand these concepts well and are a little confused.

Takeaway: Work is a measure of energy conversion.

It means that "the process of force doing work corresponds to the process of energy transformation, and the value of work is equal to the value of energy conversion".

In the kinetic energy theorem, the total work is equal to the increment (or change) of the kinetic energy of an object (when it is a unit of an object).

This total work refers to the algebraic sum of all the forces on the object to do work (regardless of concepts such as energy conversion and heat generation), and this law itself is to "see" the problem from the perspective of "work", so there is no need to pay attention to energy conversion of these things.

If we "see" the problem from the perspective of "energy transformation", we don't need to pay attention to the work done, but directly look at which energy increases and which energy decreases, and then lists the equation by the energy conservation relation.

The above two research questions have different perspectives, but the results are consistent. Because the "value of the work" is equal to the "value of the energy conversion".

For example, when the work done by sliding friction corresponds to the conversion of mechanical energy into heat energy, if the kinetic energy theorem is used, only the work of friction (regardless of the increased heat) is listed, and if it is solved by energy conversion, only the increased heat (regardless of the work of friction) is listed.

I guess you're asking about columnar and algebra at the time.

The kinetic energy theorem w=w1+w2 must be positive here.

And in algebra, according to whether the friction force is consistent with the direction of motion, if it is consistent, it is a positive sign. Otherwise, it is a minus. That is, positive or negative work.