What are the contents of the three conservation laws?

The three major conservation laws in physics are conservation of energy, conservation of momentum, and conservation of angular momentum.

Initially they were corollaries of Newton's laws, but later it was found that they were far more applicable than Newton's laws and still held true in the microscopic world.

Physics, as an experimental science, follows a path of observing the development of phenomena, explaining phenomena with theories, testing the accuracy of phenomena with experiments, and thus confirming and falsifying a theory. This is essentially a logical abstraction of the objective world, and the more obvious the phenomenon or theory, the more superficial and less applicable; On the contrary, the less obvious and the wider the scope of application, the greater the ability to make a system and the more basic it is to abstract and summarize through obvious phenomena.

Because the three conservation laws are the basis of physics, they are the law of conservation of energy, the law of conservation of momentum, and the law of conservation of angular momentum.

1. The law of conservation of energy.

The law of conservation of energy, the first law of thermodynamics, states that the total energy in a closed system remains constant. Generally speaking, the total energy is no longer just the sum of kinetic energy and potential energy, but the total amount of stationary energy, kinetic energy and potential energy. The law of conservation of energy can be formulated as:

The total energy of a system can only be changed by the amount of energy transferred to or from the system. The total energy is the sum of the mechanical energy, thermal energy, and any form of internal energy other than thermal energy of the system.

2. The law of conservation of momentum.

A system is not subject to an external force or the resultant external force is zero, and the momentum of the system remains the same. i.e. δp1 δp2

3. The law of conservation of angular momentum.

For a particle, the angular momentum theorem can be expressed as follows: the microquotient of the angular momentum of the particle to the fixed point to the time is equal to the moment of the force acting on the particle.

The three conservation laws you are talking about should be the law of conservation of momentum and the law of conservation of energy.

and the law of conservation of angular momentum.

Together, they are known as the three fundamental conservation laws of modern physics. Originally they were Newton's laws.

but later it was found that their scope of application was much broader than Newton's laws, and they were more fundamental physical laws than Newton's laws, and were a reflection of the nature of space-time. Among them, the law of conservation of momentum is derived from the translational invariance of space, the law of conservation of energy is derived from the translational invariance of time, and the law of conservation of angular momentum is derived from the rotational symmetry of space.

The law of conservation of momentum is one of the most universal and fundamental laws of nature. It is not only suitable for low-speed movement of macroscopic objects, but also for high-speed movement with microscopic objects. From microscopic particles to cosmic objects, the law of conservation of momentum always applies as long as the conservation conditions are met, no matter what the nature of the internal force is.

Conditions apply. 1.The system is not subject to external forces or combined external forces.

zero; 2.Although the resultant external force of the system is not zero, the internal force of the system is much greater than the external force, such as collision, ** and other phenomena, the momentum of the system can be regarded as approximately conserved;

3.If the system does not meet any of the above conditions in general, the total momentum of the system is not conserved. However, if the system meets any of the above conditions in a certain direction, the momentum of the system is conserved in that direction.

Note: 1) Distinguish between internal and external forces.

There must be an interacting force between the two objects at the time of collision.

The force between two objects that belong to a system is called the internal force;

The force exerted by an object outside the system is called an external force.

2) With a certain total momentum, the momentum of each object can vary greatly.

1. Conservation of electric charge.

The so-called conservation of charge relationship is an equation between the concentration of anions and cations in any electrolyte solution. The key point is that the solution is electrically neutral, that is, the number of positive charges carried by cations = the number of negative charges carried by anions.

2. Conservation of materials.

That is, a primordial element in a solution is equal to the sum of its various forms of existence in this solution, that is, the conservation of elements. At the same time, the aqueous solution must contain hydrogen and oxygen, so the medium formula of conservation of materials must have nothing to do with hydrogen and oxygen.

3. Conservation of protons.

That is, H+ is conserved, and the total number of H+ lost in the solution is equal to the total number of H+ obtained, that is, the number of protons lost by the acid and the number of protons obtained by the base are the same.

The three conservation laws you mentioned should be the three recognized laws of modern physics, namely: the law of conservation of energy, the law of conservation of momentum, and the law of conservation of angular momentum. Let's take a closer look.

First, the law of conservation of energy: the famous first law of thermodynamics, which states that the total energy in a closed (isolated) system remains constant. Generally speaking, the total energy is no longer just the sum of kinetic energy and potential energy, but the total amount of rest energy (intrinsic energy), kinetic energy, and potential energy.

Second, the law of conservation of momentum: if a system is not exposed to an external force or the vector sum of the external forces is zero, the total momentum of the system remains constant.

Third, the law of conservation of mass: it is one of the basic laws that exist in nature, also known as the law of the immortality of matter. This law has been recognized since the French chemist Lavoisier experimentally overturned the phlogiston theory in the 18th century.

In any system that is isolated from its surroundings, the total mass remains the same, regardless of the changes or processes that occur. In other words, any change, including chemical reactions and nuclear reactions, cannot eliminate matter, but only change the original form or structure of matter, so this law is also called the law of immortality of matter.

In addition, there are three conservation laws in chemistry, which are the conservation of charge, the conservation of materials, and the conservation of protons.

Conservation of charge means that the total positive charge of the cation in the solution is equal to the total negative charge of the anion.

Conservation of materials refers to the equation relationship between the quantities of key ions in a solution.

Proton conservation is actually the concentration of H+ ionized by water in solution equal to the concentration of oh- ionized by water.

The Law of Conservation of Energy – Time Translation Invariance.

The law of conservation of momentum – spatial translational invariance.

The law of conservation of angular momentum – spatial isotropy.

There are three conservation laws: the law of conservation of energy (including the law of conservation of mechanical energy), the law of conservation of momentum, and the law of conservation of angular momentum.

Conservation of mechanical energy The total amount of kinetic energy and potential energy is conserved.

And the conservation of energy includes all energy, including heat, and so on.

So the range of conservation of energy is greater than that of mechanical energy.

Mechanical energy is a manifestation of a form of energy, and conservation of mechanical energy is also a manifestation of conservation of energy. The range of use of conservation of energy is larger than that of conservation of mechanical energy, but sometimes it is easier to solve a specific problem using specific mechanical energy.

If a system is not subjected to an external force or the vector sum of the external forces is zero, then the total momentum of the system remains the same, and this conclusion is called the law of conservation of momentum.

It might be better to make an analogy:

The conservation of momentum should still be quite clear, right? So for a system, if there is no resultant force, momentum is conserved. So for a system, if there is no resultant moment, the angular momentum is conserved.

The conservation of angular momentum is in rotation"Momentum is conserved"For the contraction of the nebula, I personally believe that it cannot be explained by the conservation of angular momentum alone. (But for nebulae, the gravitational force for their moment is zero, so angular momentum is conserved.) ）

‍‍‍1.Conservation of mass. In any system of matter that is isolated from its surroundings (an isolated system), its total mass remains the same regardless of the changes or processes that occur.

2.Conservation of energy, the change in quantity of energy, follows the most universal and basic law of nature, that is, the law of conservation of energy.

3.Conservation of electric charge. The total amount of charge can neither be created nor disappear, it can only be transferred from one object to another, or from one part of an object to another This is the law of conservation of charge.

Law of Conservation of Mass: The law of the immortality of matter, the sum of the masses of the substances participating in the reaction is equal to the sum of the masses of the substances produced after the reaction.

The Law of Conservation of Energy: The first law of thermodynamics, which states that the total energy of a closed (isolated) system remains constant.

The law of conservation of electric charge: It is divided into the law of conservation of weak charge and the law of conservation of charge of strong version, and the law of conservation of charge of weak version shows that the total amount of charge of the entire universe remains constant and does not change with the evolution of time.

The three major conservations are as follows:The three major conservation values of high school chemistry are:

1. Conservation of electric charge.

i.e. the solution is always electrically neutral, so cationic.

The total amount of positive charge with the band anion.

The total amount of negative charge in the band.

2. Conservation of materials.

That is, the specific proportional relationship between some elements present in the composition of the added solute, since there must be H and O elements of water in the aqueous solution, the equation in the conservation of materials must be the relationship of non-H and O elements.

3. Conservation of protons.

That is, the total amount of H+ is conserved, the total amount of H+ lost in the solution is equal to the total number of H+ obtained, or the total amount of H+ ionized by water in the aqueous solution is always equal to the total amount of Oh- ionized by water, and the conservation of materials and charge can also be introduced.

Jian Tong dismantled and punched:Chemistry is a kind of natural science, mainly at the molecular and atomic level, to study the composition, properties, structure and change laws of matter, and to create new substances (the essence of the crack is the original non-existent molecular annihilation in nature). The world is made up of matter, and there are two main forms of change: chemical and physical (and nuclear reactions).

The three conservation laws of physics refer to mechanical.

The law of conservation of momentum, the law of conservation of angular momentum, the law of conservation of mechanical energy, the conservation of mass is in chemistry.

Physics has nuclear reactions, and there will be a loss of mass, so there is no such thing as conservation of mass in physics, and conservation of charge is also a law of chemistry.

There are three conservation laws in chemistry: conservation of charge, conservation of materials, and conservation of protons.

The three conservation formulas are conservation of charge, conservation of materials , and conservation of protons.

Material balance: C(Na+)=2C(S2-)+2C(Hs-)+2C(H2S).

Charge balance: C(Na+)+C(H+)=2C(S2-)+S(Hs-)+C(OH-).

Proton balance: c(h+)=c(oh-)-c(hs-)-2c(h2s)<>

Conservation does not represent a physical quantity.

It is constant, but the increase of a certain physical quantity is always equal to the inflow (negative increase represents decrease, and negative inflow represents outflow). The increase is not equal to the inflow (e.g. the increase is positive, the inflow is 0) and it is not conserved (e.g., entropy).

In general, there are about twelve conservation laws in physics. The law of conservation of energy.

The law of conservation of momentum, the law of conservation of mass.

Law of conservation of electric charge, etc.

The law of conservation of momentum and energy, as well as the law of conservation of angular momentum, are the three fundamental conservation laws in modern physics.

There are three conservation laws: the law of conservation of momentum, the law of conservation of energy, and the law of conservation of mechanical energy.

There are only two conservation laws in physics: the law of conservation of energy and the law of conservation of momentum.

1. The law of conservation of energy.

Form of expression. Conservative mechanical system: In the case of only conservative force doing work, the energy of the system is expressed as mechanical energy (kinetic energy and potential energy), and the conservation of energy is specifically expressed as the law of conservation of mechanical energy.

Thermodynamic system: energy is expressed as internal energy, heat and work, and the expression form of conservation of energy is the first law of thermodynamics.

Nuclear mechanical system: In the process of nuclear fusion and nuclear fission, a large amount of energy is produced at the same time, a large number of particles are ejected, so the mass of the object is decreasing. If the process of nuclear fusion and nuclear fission is reversible, then a large number of particles and a large amount of energy are required to constitute the inverter process of nuclear fusion and nuclear fission.

Between nuclear fusion and nuclear fusion inversion, nuclear fission and nuclear fission inversion, their energy is conserved, and their mass is also conserved.

The total energy flowing into the system must be equal to the total energy flowing out of the system plus the change in the energy inside the system, and the energy can be transformed, from one form to another.

The increase in stored energy in the system is equal to the energy entering the system minus the energy leaving the system.

Significance. The law of conservation of energy is one of the most common and important fundamental laws of nature. From physics and chemistry to geology and biology, to cosmic celestial bodies.

As small as the inside of the nucleus, as long as there is energy conversion, it must obey the law of conservation of energy. From daily life to scientific research and engineering technology, this law plays an important role. Human beings' utilization of various energies, such as coal, oil and other fuels, as well as hydropower, wind energy, nuclear energy, etc., is achieved through energy conversion.

The law of conservation of energy is a powerful way for people to understand and use nature.

Three formulations of the law.

Perpetual motion machines cannot be caused, the law of conversion and conservation of energy and the first law of thermodynamics. These three statements are described in the literature as follows:"The first law of thermodynamics is the law of conservation of energy.

According to the law of conservation of energy, ,......The so-called perpetual motion machine must not be built. Conversely, the law of conservation of energy can be derived from the failure of a perpetual motion machine. "It is not difficult to see here that the three formulations are completely equivalent.

However, the author believes that this kind of equivalence is the modern value given to them by modern people, and if we examine it from the perspective of historical development, we will find that the three expressions have another side of continuity, but there is also a different side. This difference reflects the different stages of human cognition of the laws.

2. The law of conservation of momentum.

Content: A system is not subject to external forces or has zero external forces, and the momentum of the system remains constant. i.e. δp1 δp2

The law of conservation of energy.