Examples of changes in the internal energy of the body when hitting. Methods for changing internal energy. Examples of changes in internal energy

How to change the mechanical energy of the body? Yes, very simple. Change its location or give it acceleration. For example, kick the ball or raise it above the ground.

In the first case, we will change its kinetic energy, in the second potential. What is the case with internal energy? How to change the internal energy of the body? To begin with, we'll see what it is. Internal energy is the kinetic and potential energy of all particles from which the body consists. In particular, the kinetic energy of particles is the energy of their movement. And the speed of their movement, as is known, depends on the temperature. That is, a logical conclusion - increasing the body temperature, we will increase its internal energy. The easiest way to increase body temperature is heat exchange. When contacting bodies with different temperatures, a colder body heats up due to warmer. The warmer body in this case is cooled.

A simple daily example: a cold spoon in a cup with hot tea is very quickly heated, and tea at the same time cool down. Increased body temperature is possible in other ways. How do we do everything when our face or hands freeze on the street? We are three of them. During friction, the items are heated. Also, items are heated at shuffles, pressure, that is, in other words, when interacting. Everyone knows how the fire was mined in ancient times - either rubbed the bores about each other, or stucked silicon on another stone. Also in our time in silicon lighters, the friction of the metal rod about flint is used.

So far, it was about changing the internal energy by changing the kinetic energy of the components of its particles. What about the potential energy of the same particles? As is known, the potential energy of particles is the energy of their interpordability. Thus, to change the potential energy of body particles, we need the body to deform: compress, twist, and so on, that is, to change the location of the particles relative to each other. This is achieved by influencing the body. We change the speed of individual parts of the body, that is, we take work on it.

Examples of changes in internal energy

Thus, all cases of influence on the body in order to change its internal energy are achieved in two ways. Either by transferring it heat, that is, heat transfer, or by changing the speed of its particles, that is, committing work over the body.

Examples of changes in internal energy - It is almost all the processes occurring in the world. The internal energy of particles does not change in the case when absolutely nothing happens to the body, they agree, extremely rarity - the law of energy conservation is valid. There is something around us all the time. Even with the subjects, with whom, at first glance, nothing happens, in fact various changes in the changes are happening: minor changes in temperature, small deformations, and so on. The chair begins under our weight, the book on the shelf slightly changes the temperature from each movement of the air, not to mention the drafts. Well, as for living bodies - it's clear here without words that something is happening in them all the time, and the internal energy changes almost at every moment of time.

676. Is the thermal movement of the rotation of the artificial satellite around the Earth?
No, it's not. The heat movement is the erratic movement of molecules and atoms, of which the body consists.

677. Movement of gas molecules can be called a thermal motion?
The heat movement is the process of chaotic particle movement. Gas molecules are moving chaotically, so their movement can be called thermal. 678. Is it possible to say that the diffusion phenomenon is caused by thermal motion?
The thermal movement is the process of chaotic particle movement in the substance. Diffusion is the process of mutual penetration of atoms and molecules of one substance to another. The process of mutual penetration is caused by the chaotic movement of atoms and molecules, therefore, the diffusion phenomenon is caused by thermal motion.

679. What happens to the thermal motion while raising the temperature?
With an increase in temperature, the speed of movement of molecules is increased.

680. Will the kinetic and potential energy of water molecules change in a tightly clogged can with cold water, if it is immersed in hot water?
The temperature in the bank will increase due to the phenomenon of heat exchange, thereby increasing kinetic energy. Potential energy will remain unchanged, as it depends on the distance between molecules, and it does not change.

681. Freely falling ball, hitting asphalt, jumps again, but never rises to the initial height, which fell. Why?
Because the kinetic energy of the ball is spent on overcoming the resistance of the air and the forces of earthly gravity.

682. Up Take a coin. What transformations of energy occur when the coin is lifted? when it falls? At the moment of hitting the asphalt?
With an increase in the height of the climb of the coin, its potential energy increases, and kinetic decreases. In the highest point, the potential energy is maximum, and the kinetic is minimal. At the beginning of the fall, kinetic energy increases, and potential decreases. At the time before the blow, the kinetic energy is maximum, and the potential is minimal. When you hit, the conversion of part of the energy in heat, as well as in the energy of the deformation.

683. Why when you hit asphalt, the coin heats up?
Because part of the energy of the coin turns into thermal.

684. One glass of hot water is poured, in the other - the cold water of the same mass. In which glass water has greater internal energy?
In a glass with hot water, molecules are moving faster than in cold. Therefore, hot water has greater inner energy.

685. Give examples of changes in the internal energy of bodies when compressing them.
Heating air in the piston of the pump.

686. How is the internal energy of bodies when friction? Give examples.
Increases. Sharpening knife on a grinding stone; friction of car tires when braking.

687. Is the inner energy of the bodies change when hitting? Give examples.
When hit, the internal energy of the bodies increases. Work hammer; rebound ball from the floor.

688. Why is the change in the inner energy of the spring when it is compressed?
When compressing the spring increases its potential energy. Consequently, internal energy increases.

689. Does the internal gas energy change occurs when expanding it?
When expanding gas produces work against external forces, the internal energy decreases in this case.

690. What is happening with the internal energy of liquid and solid when they are heated?
There is an increase in internal energy due to an increase in the speed of the particle movement.

691. Does the inner energy of ice change in its melting?
When melting ice, the internal energy increases due to the heat of heat by radiation and heat transfer.

692. The strength of friction makes work over the body. What features indicate the change in the inner energy of the body?
When completing the friction work, the body is heated, the kinetic energy increases and causes an increase in internal energy.

Tasks: 1. After processing on a sharpening circle, the chisel becomes hot. The chisel, taken out of the mountain, is also hot. Is the reason for increasing the temperature of the chisel? 2. With the friction of the head of the match about the boxes, the match flammifies. Explain the phenomenon. 3. The match lights up with friction of it about boxes. She flashes and when making it a candle flame. What is the similarity and distinction of the reasons leading to the ignition of matches in both cases. 4. Give examples of changing the internal energy of the body in the process of performing work when: friction, impact, compression. 5. Why saw heats up if she saw a long time? 6. Why, if you quickly slide down the six or rope, can you burn your hands?

7. Why skates easily slide on ice, and on the glass, the surface of which is smoother, is impossible to ride ice skates? 8. Why, when driving a nail his hat heats up weakly, and when a nail is already drunk, then just a few shots to heat the hat strongly? 9. What is the cause of strong heating and combustion of artificial earth satellites when they enter them into the lower dense layers of the atmosphere?