What is the heat of frictional heat generation Frictional heat generation is common sense, why can f

Friction generates heat, yesMechanical energyThe process of conversion into internal energy, where "heat" refers to internal energy.

The temperature of an object increases because the energy inside the object increases. And there are two ways to increase the internal energy of an object: absorbing heat and external force doing work on the object. Frictional heat generation is the increase in temperature due to the work done by external force on the object, so it is the increase of the internal energy of the object first.

Frictional heat generation is the increase of internal energy and then the increase of temperature. In real life, the meaning of the word "hot" generally has several meanings: temperature, internal energy, and heat, such as: the word "hot" in "the weather is really hot" refers to temperature; The word "hot" in "heating" and "exothermy" refers to heat.

Frictional heat generation is an abbreviation. Specifically, frictional heat generation is the heat energy produced during the friction process. More precisely, it is the internal energy generated during the friction process. Frictional heat generation refers to a kind of energy, which is generated by friction, and the energy form is content.

The essence of frictional thermogenesis

The process by which molecules on the surface of an object rubbing against each other collide with each other. Suppose an object is at rest and another object is moving relative to that object. Then in this process, the molecules in the stationary object are struck and some or all of the directional kinetic energy of the molecules in the moving object is obtained.

The molecule that obtains this directional kinetic energy will collide with other molecules around it, because the collision between the molecules is extremely frequent, and the direction of the impact is random, therefore, the original directional kinetic energy is finally transformed into irregular kinetic energy, that is, the kinetic energy of thermal motion increases. As a result, the surface of the object that rubs against each other is macroscopically manifested as an increase in internal energy and an increase in temperature.

Frictional heat generation is the process of converting mechanical energy into internal energy, and "heat" here refers to internal energy.

Endothermic heating is the amount of heat absorbed during heat transfer, and "heat" here refers to heat. In ancient times, there were two different views on heat, one was to regard heat as a special substance; One holds that heat is some form of motion of matter.

The essence of frictional thermogenesis

Scientists have further studied the relationship between heat and work, especially the British scientist Joule has done a lot of experiments to quantitatively study the relationship between heat and work, proving that how much mechanical work is done, how much mechanical energy is converted into heat as much energy. Joule's work, showing that heat is not a special substance, and at the same time laying the foundation for the law of conservation of energy.

The establishment of the law of conservation of energy completely negated the theory of thermal mass, and at the same time opened the way for the development of the theory of molecular motion. After a long period of research by scientists, the idea that heat is a form of motion has finally become an accepted truth. People recognize:

The macroscopic thermal phenomenon turns out to be the manifestation of the irregular movement of a large number of molecules inside an object.

Because during the friction process, the molecules between the objects will move violently, and there will be irregular motion performance, which will generate heat.

This is because when friction occurs, there is a violent movement of molecules between objects, so heat is generated.

This is because in the process of friction, this mechanical energy is converted into heat energy, so that friction can generate heat.

1. Friction generates heat, and the "heat" here refers to: internal energy. Friction is the process by which the work done by the applied force is converted into the internal energy of the object, the internal energy of the object increases, the speed of particle motion accelerates, and the temperature increases.

2. Internal energy (internalenergy) is the statistical average of the sum of the random motion energy of molecules from a microscopic point of view. In the absence of an external field, the energy of the random motion of the 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.

Categories: Education Science >> Admission >> High School Entrance Examination Question Description:

Is it internal or external to overcome friction and do work? Why did the last calorie increase?

Analysis: This is the internal work, at this time, the mechanical energy overcomes the friction to do the work, the mechanical energy is converted into the internal energy of the object, and the irregular movement of the molecules accelerates, so the temperature rises! Because heat is generated as a result of the constant movement of particles inside an object!

In general, under certain circumstances, the mass of the object decreases and the temperature decreases. The internal energy of the object is increased and the temperature rises!

On the other hand, your question is also problematic, because heat is the amount of energy transferred by an object in the process of heat transfer, and it is a process quantity, and it is meaningless to simply say how much heat there is in an object or to say that the heat of an object increases or decreases!

The process of friction is essentially the process by which molecules on the surface of an object rubbing against each other collide with each other. Suppose an object is at rest and another object is moving relative to that object.

In this process, the molecules in the stationary object are impacted, because the collisions between the molecules are extremely frequent, and the direction of the impact is random, therefore, the original directional kinetic energy is finally transformed into irregular kinetic energy, that is, the kinetic energy of thermal motion increases.

Knowledge developmentThe formula for frictional heat generation is: q=f x;

In the formula, q is frictional heat generation, which represents a kind of energy in j.

x refers to the relative displacement between two objects.

f refers to sliding friction and f = n.

As mentioned earlier, x refers to the relative displacement between two objects, i.e., between the objects, the relative slippage has occurred.

The meaning of x in the equation is that two objects must have relative sliding, which means that there must be sliding friction at the interface of two objects, not static friction; Static friction requires that there can be no relative sliding between two objects.