Define the physical quantity mass. What is mass

WEIGHT

WEIGHT

(lat. massa). 1) the amount of substance in the object, regardless of the form; body, matter. 2) in the hostel: a significant amount of something.

, 1910 .

WEIGHT

1) in physics - the amount of matter contained in a given body; 2) set; 3) a substance that does not have a definite form; 4) in factories, this is sometimes the name of the material that directly serves for the dressing of manufactured products (paper pulp, wood pulp, porcelain pulp); 5) mister (in the language of Negroes in America); 6) bankruptcy estate for commercial. The language refers to all available sources from which the debts of the bankrupt person must be paid. See COMPETITION.

Dictionary of foreign words included in the Russian language. - Pavlenkov F., 1907 .

WEIGHT

1) the amount of matter in the physical body; 2) heavy body; hence the word massive; 3) some materials from which various products are prepared, for example, the molten mass of cast iron, the mass of liquid glass, paper m., etc.; 4) bankruptcy estate - a set of sources from which the debt of a person over whose affairs a bankruptcy has been established (i.e., a temporary administration drawn up by creditors from several persons at their choice from among themselves) can be paid to clarify the true situation of an insolvent debtor, to put in order bills and payment of debts); 5) among American blacks - "mass" means master.

A complete dictionary of foreign words that have come into use in the Russian language. - Popov M., 1907 .

WEIGHT

On the Negro. language: sir.

, 1865 .

WEIGHT

In Negro: sir.

Dictionary of foreign words included in the Russian language. - Chudinov A.N., 1910 .

WEIGHT

lat. massa, French masse. The amount of matter in an object.

Explanation of 25,000 foreign words that have come into use in the Russian language, with the meaning of their roots. - Mikhelson A.D., 1865 .

Weight

(lat. massa com, piece)

1) physical. quantity, one of the main characteristics of matter, which determines its inert and gravitational properties; m. as a measure of the inertia of the body with respect to the force acting on it (m. of rest) and m. as a source of the gravitational field are equal (equivalence principle); in the international system of units (si), m is expressed in kilograms;

2) a substance in the form of a thick or semi-liquid mixture of smth.; semi-finished product in various industries, for example, paper m., porcelain m.;

3) a lot, a huge amount of something, someone;

4) masses - wide circles of the population, the people.

New dictionary of foreign words.- by EdwART,, 2009 .

Weight

masses, w. [Latin. massa]. 1. A lot, a large number. Mass of people. Tired of the mass of impressions. 3. Pile, bulk. The dark mass of an armadillo was approaching the shore. || A concentrated part of something, an overwhelming amount. The bulk of the artillery is located on the flank. 4. A mixture, a doughy substance, which is a semi-finished product in various industries (technical). Wood pulp. porcelain mass. 5. Weight and inertia inherent in matter and energy (physical).

A large dictionary of foreign words. - Publishing house "IDDK", 2007 .

Weight

s, and. (German Masse lat. māssa kom, heap).
1. pl. No, physical A quantity that measures the amount of matter in a body, a measure of the inertia of a body with respect to the force acting on it. The acceleration of a body depends on its mass..
2. Doughy shapeless substance, thick mixture. Molten m. Syrkovaya m.
3. pl. No, trans. About something. very large, concentrated in one place. dark m. building.
4. pl. No, what, unfold Many, many. M. people. M. books.
|| Wed myriads.
5. pl. Wide circles of the population, people. The will of the masses. Knowledge - to the masses.
Mass -
1) characteristic of the mass of people ( mass demonstrations);
2) produced in large quantities mass production of goods);
3) intended for the masses ( book published in bulk);
4) belonging to the masses ( mass audience).

Explanatory Dictionary of Foreign Words L. P. Krysina.- M: Russian language, 1998 .

See what "MASS" is in other dictionaries:

Massage, ah, eat... Russian word stress

weight- uh. masse f., German. Masse, Massa, lat. massa lump, thickness, pile. 1. This word generally means 1) a heap, a heap, a heap, a number of many parts of the same or different kind, which together make up a body or a whole. Jan. 1804. Melt it ... ... Historical Dictionary of Gallicisms of the Russian Language

See a lot, mob... Dictionary of Russian synonyms and expressions similar in meaning. under. ed. N. Abramova, M .: Russian dictionaries, 1999. mass piece, many, crowd, mob, many ... Synonym dictionary

WEIGHT- (1) one of the main physical characteristics of matter, which is a measure of its inertial (see) and gravitational (see) properties. In the classical (see), the mass is equal to the ratio of the force F acting on the body to the acceleration a acquired by it: m \u003d F / a (see). ... ... Great Polytechnic Encyclopedia

WEIGHT, masses, women. (lat. massa). 1. A lot, a large number. Mass of people. Tired of the mass of impressions. A lot of trouble. 2. more often pl. Wide circles of workers, the population. The working masses. Stay away from the masses. The vital interests of the peasant ... ... Explanatory Dictionary of Ushakov

- - 1) in the natural scientific sense, the amount of matter contained in the body; the resistance of a body to a change in its motion (inertia) is called inertial mass; the physical unit of mass is the inert mass of 1 cm3 of water, which is 1 g (gram ... ... Philosophical Encyclopedia

- (from the Latin massa lump, lump, piece), a fundamental physical quantity that determines the inert and gravitational properties of all bodies from macroscopic bodies to atoms and elementary particles. As a measure of inertia, mass was introduced by I. Newton with ... ... Modern Encyclopedia

One of the main physical characteristics of matter, which determines its inert and gravitational properties. In classical mechanics, the mass is equal to the ratio of the force acting on the body to the acceleration it causes (Newton's 2nd law) in this case, the mass ... ... Big Encyclopedic Dictionary

MASS, better masa female, lat. substance, body, matter; | thickness, the totality of matter in a known body, its materiality. The volume of the atmosphere is vast, and the mass is negligible. Such a mass will crush everything. A mass of goods, a heap, an abyss. | merchant all property... Dahl's Explanatory Dictionary

- (symbol M), a measure of the amount of a substance in an object. Scientists distinguish two types of masses: gravitational mass is a measure of mutual attraction between bodies (earth attraction), expressed by Newton in the law of universal gravitation (see GRAVITATION); inert... Scientific and technical encyclopedic dictionary

Weight- a physical quantity that is inseparably inherent in matter and determines its inertial, energy and gravitational properties. In classical physics, it is strictly subject to the conservation law, on the basis of which classical mechanics is built. In quantum mechanics, a special form of energy and, as such, also the subject of the (mass-energy) conservation law.

Mass is denoted by the Latin letter m

The SI unit for mass is the kilogram. In the Gaussian system, mass is measured in grams. In atomic physics, it is customary to equate mass to atomic mass unit, in solid state physics - to the mass of an electron, in high energy physics, mass is measured in electronvolts. In addition to these units, there are a huge number of historical units of mass that have been preserved in certain areas of use: pound, ounce, carat, ton etc. In astronomy, the unit for comparing the masses of celestial bodies is the mass of the Sun.

Body mass is a physical quantity that characterizes its inertial and gravitational properties.

In classical physics, mass is a measure of the amount of matter contained in a body. The law of conservation of mass is valid here: the mass of an isolated system of bodies does not change with time and is equal to the sum of the masses of the bodies that make it up.

In Newtonian mechanics, body mass is a scalar physical quantity, which is a measure of its inertial properties and a source of gravitational interaction. In classical physics, mass is always a positive quantity.

Mass is an additive quantity, which means: the mass of each set of material points (\(m \) ) is equal to the sum of the masses of all individual parts of the system (\(m_i \) )

\[ m=\sum\limits_(i=1)^(n)(m_i) \]

In classical mechanics, one considers:

• body mass is not dependent on the movement of the body, on the impact of other bodies, the location of the body;
• the law of conservation of mass is fulfilled: the mass of a closed mechanical system of bodies is constant in time.

As a measure of body inertia, mass is included in Newton's second law, written in a simplified (for the case of constant mass) form:

\[ \LARGE m = \dfrac(F)(a) \]

where \ (a \) is acceleration, and \ (F \) is the force that acts on the body

Mass types

Strictly speaking, there are two different quantities that have the common name "mass":

• inertial mass characterizes the ability of a body to resist a change in its state of motion under the action of a force. Provided that the force is the same, an object with less mass changes its state of motion more easily than an object with more mass. Inertial mass appears in a simplified form of Newton's second law, as well as in the formula for determining the momentum of a body in classical mechanics.
• gravitational mass characterizes the intensity of interaction of the body with the gravitational field. It appears in Newton's law of universal gravitation.

Although inertial mass and gravitational mass are conceptually different concepts, all experiments known to date show that these two masses are proportional to each other. This allows you to build a system of units so that the unit of measurement of all three masses is the same, and they are all equal to each other. Almost all systems of units are built on this principle.

In general relativity, inertial and gravitational masses are considered to be completely equivalent.

Inertia is the property of various material objects to acquire different accelerations under the same external influences from other bodies. Inherent in different bodies to varying degrees. The property of inertia shows that it takes time (distance) to change the speed of a body. The harder it is to change the speed of a body, the more inert it is.

Mass is a scalar quantity, which is a measure of the inertia of a body during translational motion. (When rotating - the moment of inertia). The more inert the body, the greater its mass. The mass defined in this way is called inertial (in contrast to the gravitational mass, which is determined from the law of universal gravitation).

Mass of elementary particles

Mass, or rather rest mass, is an important characteristic of elementary particles. The question of what causes the values ​​of the mass of particles observed in experiment is an important problem in elementary particle physics. So, for example, the mass of a neutron is somewhat larger than the mass of a proton, which is due to the difference in the interaction of quarks that make up these particles. The approximate equality of the masses of some particles makes it possible to combine them into groups, treating them as different states of one common particle with different values ​​of the isotopic spin.

Mass (physical value) Weight, a physical quantity, one of the main characteristics of matter, which determines its inertial and gravitational properties. Accordingly, M. is inert and M. gravitational (heavy, gravitating).

The concept of M. was introduced into the mechanics of I. Newton. In Newton's classical mechanics, M. is included in the definition of momentum ( momentum) body: the momentum p is proportional to the speed of the body v,

p = m.v.

The coefficient of proportionality - a constant value m for a given body - is the M. of the body. An equivalent definition of M. is obtained from the equation of motion of classical mechanics

f = ma.

Here M. is the coefficient of proportionality between the force acting on the body f and the acceleration of the body caused by it a. The mass defined by relations (1) and (2) is called inertial mass, or inertial mass; it characterizes the dynamic properties of the body, is a measure of the inertia of the body: at a constant force, the greater the M. of the body, the less acceleration it acquires, that is, the slower the state of its movement changes (the greater its inertia).

Acting on different bodies with the same force and measuring their accelerations, one can determine the ratios of M. of these bodies: m 1 :m 2 :m 3 ... = a 1 : a 2 : a 3 ...; if one of the M. is taken as a unit of measurement, one can find the M. of the remaining bodies.

In Newton's theory of gravitation, magnetism appears in a different form - as a source of the gravitational field. Each body creates a gravitational field proportional to the M. of the body (and is affected by the gravitational field created by other bodies, the strength of which is also proportional to the M. bodies). This field causes the attraction of any other body to this body with a force determined by Newton's law of gravity:

where r is the distance between the bodies, G is the universal gravitational constant, a m 1 and m 2 ‒ M. attracting bodies. From formula (3) it is easy to obtain a formula for weightР bodies of mass m in the Earth's gravitational field:

P \u003d m g.

Here g = G M / r 2 is the free fall acceleration in the Earth's gravitational field, and r » R is the Earth's radius. The mass determined by relations (3) and (4) is called the gravitational mass of the body.

In principle, it does not follow from anywhere that magnetism, which creates a gravitational field, also determines the inertia of the same body. However, experience has shown that inertial magnetism and gravitational magnetism are proportional to each other (and with the usual choice of units of measurement, they are numerically equal). This fundamental law of nature is called the principle of equivalence. Its discovery is associated with the name of G. Galilee, who established that all bodies on Earth fall with the same acceleration. A. Einstein put this principle (which he formulated for the first time) at the basis of the general theory of relativity (cf. gravity). The principle of equivalence has been established experimentally with very high accuracy. For the first time (1890‒1906), a precision check of the equality of inert and gravitational magnetism was carried out by L. Eötvös, who found that M. matched with an error of ~ 10-8 . In 1959–64 the American physicists R. Dicke, R. Krotkov, and P. Roll reduced the error to 10-11 , and in 1971 the Soviet physicists V. B. Braginsky and V. I. Panov reduced the error to 10-12 .

The principle of equivalence makes it possible to most naturally determine the M. of a body weighing.

Initially, mass was considered (for example, by Newton) as a measure of the amount of matter. Such a definition has a clear meaning only for comparing homogeneous bodies built from the same material. It emphasizes the additivity of the M. ‒ The M. of a body is equal to the sum of the M. of its parts. The mass of a homogeneous body is proportional to its volume, so we can introduce the concept density‒ M. units of body volume.

In classical physics, it was believed that the M. of a body does not change in any processes. This corresponded to the law of conservation of matter (substance), discovered by M. V. Lomonosov and A. L. Lavoisier. In particular, this law stated that in any chemical reaction the sum of M. of initial components is equal to the sum of M. of final components.

The concept of M. has acquired a deeper meaning in the mechanics of special. A. Einstein's theory of relativity (see. Relativity theory), which considers the movement of bodies (or particles) with very high speeds - comparable to the speed of light with » 3×1010 cm/sec. In the new mechanics - it is called relativistic mechanics - the relationship between the momentum and the velocity of a particle is given by the relation:

At low speeds (v<< с ) это соотношение переходит в Ньютоново соотношение р = mv . Поэтому величину m 0 называют массой покоя, а М. движущейся частицы m определяют как зависящий от скорости коэфф. пропорциональности между р и v :

With this formula in mind, in particular, they say that the momentum of a particle (body) increases with an increase in its velocity. Such a relativistic increase in the momentum of a particle as its velocity increases must be taken into account when designing particle accelerators high energies. M. rest m 0 (M. in the reference frame associated with the particle) is the most important internal characteristic of the particle. All elementary particles have strictly defined values ​​of m 0 inherent in this kind of particles.

It should be noted that in relativistic mechanics the definition of M. from the equation of motion (2) is not equivalent to the definition of M. as a proportionality factor between the momentum and velocity of a particle, since acceleration ceases to be parallel to the force that caused it, and M. turns out to depend on the direction of the particle's velocity.

According to the theory of relativity, the momentum of a particle m is related to its energy E by the relation:

M. rest determines the internal energy of the particle - the so-called rest energy E 0 \u003d m 0 c 2 . Thus, energy is always associated with M. (and vice versa). Therefore, there is no separate (as in classical physics) law of conservation of M. and the law of conservation of energy - they are merged into a single law of conservation of total (that is, including the rest energy of particles) energy. An approximate division into the law of conservation of energy and the law of conservation of magnetism is possible only in classical physics, when the particle velocities are small (v<< с ) и не происходят процессы превращения частиц.

In relativistic mechanics, magnetism is not an additive characteristic of a body. When two particles combine to form one compound stable state, an excess of energy (equal to binding energy) DE , which corresponds to M. Dm = DE / s 2 . Therefore, the M. of a composite particle is less than the sum of the M. of the particles that form it by the value DE / s 2 (so-called mass defect). This effect is especially pronounced in nuclear reactions. For example, the M. of a deuteron (d) is less than the sum of the M. of a proton (p) and a neutron (n); defect M. Dm is associated with the energy E g of the gamma quantum (g) produced during the formation of a deuteron: p + n ® d + g, E g \u003d Dm c 2 . The defect of M., which occurs during the formation of a composite particle, reflects the organic connection of M. and energy.

The unit of M. in the CGS system of units is gram, and in International system of units SI - kilogram. The mass of atoms and molecules is usually measured in atomic mass units. It is customary to express the mass of elementary particles either in units of the mass of the electron m e , or in energy units, indicating the rest energy of the corresponding particle. So, the M. of an electron is 0.511 MeV, the M. of a proton is 1836.1 meV, or 938.2 MeV, etc.

The nature of mathematics is one of the most important unsolved problems of modern physics. It is generally accepted that the magnetism of an elementary particle is determined by the fields associated with it (electromagnetic, nuclear, and others). However, the quantitative theory of M. has not yet been created. There is also no theory explaining why the M. of elementary particles form a discrete spectrum of values, and even more so, allowing to determine this spectrum.

In astrophysics, the magnetism of a body that creates a gravitational field determines the so-called gravity radius bodies R gr = 2GM/c 2 . Due to gravitational attraction, no radiation, including light, can go outside, beyond the surface of a body with a radius R £ R gr . Stars of this size would be invisible; so they were called black holes". Such celestial bodies must play an important role in the universe.

Lit .: Jammer M., The concept of mass in classical and modern physics, translated from English, M., 1967; Khaikin S. E., physical foundations of mechanics, M., 1963; Elementary textbook of physics, edited by G. S. Landsberg, 7th ed., vol. 1, M., 1971.

Ya. A. Smorodinsky.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

See what "Mass (physical quantity)" is in other dictionaries:

- (lat. massa, lit. lump, lump, piece), physical. value, one of the har to matter, which determines its inertial and gravitational forces. sv. The concept of "M." was introduced into mechanics by I. Newton in the definition of the momentum (number of motion) of the body momentum p proportional. ... ... Physical Encyclopedia

- (lat. massa). 1) the amount of substance in the object, regardless of the form; body, matter. 2) in the hostel: a significant amount of something. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. MASS 1) in physics, quantity ... ... Dictionary of foreign words of the Russian language

- - 1) in the natural scientific sense, the amount of matter contained in the body; the resistance of a body to a change in its motion (inertia) is called inertial mass; the physical unit of mass is the inert mass of 1 cm3 of water, which is 1 g (gram ... ... Philosophical Encyclopedia

WEIGHT- (in the ordinary view), the amount of substance contained in a given body; the exact definition follows from the basic laws of mechanics. According to Newton's second law, "the change in motion is proportional to the acting force and has ... ... Big Medical Encyclopedia

Phys. the value characterizing the dynamic. sv va tepa. I. m. is included in Newton's second law (and, thus, is a measure of the body's inertia). Equal to gravity. mass (see MASS). Physical Encyclopedic Dictionary. Moscow: Soviet Encyclopedia. Editor-in-Chief A... Physical Encyclopedia

- (heavy mass), physical. a value that characterizes the body's power as a source of gravity; equal to the inertial mass. (see MASS). Physical Encyclopedic Dictionary. Moscow: Soviet Encyclopedia. Editor-in-Chief A. M. Prokhorov. 1983... Physical Encyclopedia

Phys. a value equal to the ratio of mass to count in VA. Unit M. m. (in SI) kg / mol. M \u003d m / n, where M M. m. in kg / mol, m is the mass in va in kg, n is the number in va in moles. Numerical value M. m., vyraz. in kg / mol, equally refers. molecular weight divided by... Big encyclopedic polytechnical dictionary - size, character ka physical. objects or phenomena of the material world, common to many objects or phenomena as qualities. relation, but individual in quantities. relationship for each of them. For example, mass, length, area, volume, electric power. current F ... Big encyclopedic polytechnic dictionary

In life, we very often say: “weight 5 kilograms”, “weighs 200 grams” and so on. And yet we do not know that we are making a mistake by saying so. The concept of body weight is studied by everyone in the course of physics in the seventh grade, however, the erroneous use of some definitions has mixed up with us so much that we forget what we have learned and believe that body weight and mass are one and the same.

However, it is not. Moreover, the mass of the body is a constant value, but the weight of the body can change, decreasing down to zero. So what is wrong and how to speak correctly? Let's try to figure it out.

Body weight and body weight: calculation formula

Mass is a measure of the inertia of the body, it is how the body reacts to the impact applied to it, or itself acts on other bodies. And the weight of the body is the force with which the body acts on a horizontal support or vertical suspension under the influence of the Earth's gravity.

Mass is measured in kilograms, and body weight, like any other force, in newtons. The weight of a body has a direction, like any force, and is a vector quantity. Mass has no direction and is a scalar quantity.

The arrow that indicates the weight of the body in the figures and graphs is always directed downward, as well as the force of gravity.

Body weight formula in physics is written as follows:

where m - body weight

g - free fall acceleration = 9.81 m/s^2

But, despite the coincidence with the formula and direction of gravity, there is a serious difference between gravity and body weight. Gravity is applied to the body, that is, roughly speaking, it is it that presses on the body, and the weight of the body is applied to the support or suspension, that is, here the body is already pressing on the suspension or support.

But the nature of the existence of gravity and body weight is the same attraction of the Earth. Strictly speaking, the weight of the body is a consequence of the force of gravity applied to the body. And just like gravity, body weight decreases with height.

Body weight in weightlessness

In a state of weightlessness, the weight of the body is zero. The body will not put pressure on the support or stretch the suspension and will not weigh anything. However, it will still have mass, since in order to give the body any speed, it will be necessary to apply a certain effort, the greater, the greater the mass of the body.

In the conditions of another planet, the mass will also remain unchanged, and the weight of the body will increase or decrease, depending on the force of gravity of the planet. We measure body weight with weights, in kilograms, and to measure body weight, which is measured in Newtons, we can use a dynamometer, a special device for measuring force.

Body mass

the main mechanical quantity that determines the amount of acceleration imparted to the body by a given force. The masses of bodies are directly proportional to the forces imparting equal accelerations to them and inversely proportional to the accelerations imparted to them by equal forces. So the relationship between M. (T), force f, and acceleration a, can be expressed by the formula

i.e., M. is numerically equal to the ratio between the driving force and the acceleration produced by it. The value of this ratio depends solely on the moving body, so the value of M fully characterizes the body from the mechanical point of view. The view of the real value of M. changed with the development of science; At present, in the system of absolute mechanical units, M. is taken as the amount of substance, as the main quantity, by which the force is then determined. From a mathematical point of view, it makes no difference whether M. is taken as an abstract factor by which the accelerating force must be multiplied in order to obtain the driving force, or as the amount of matter: both assumptions lead to the same results; from the physical point of view, the latter definition is undoubtedly preferable. First, matter, as the amount of matter in a body, has real significance, because not only mechanical, but also many physical and chemical properties of bodies depend on the amount of matter in a body. Secondly, the basic quantities in mechanics and physics must be accessible to direct, possibly accurate measurement; we can measure force only with spring force meters - instruments that are not only not accurate enough, but also not reliable enough, due to the variability of the elasticity of the springs over time. Lever scales do not in themselves determine the absolute value of the weight as a force, but only the ratio or equality of the weight (see Weight and weighing) of two bodies. On the contrary, balances make it possible to measure or compare the M. of bodies, since, due to the equality of the acceleration of the fall of all bodies on the same point on the earth, equal weights of two bodies correspond to equal M. Balancing a given body with the required number of accepted units of M., we find the absolute value M. him. For unit M. is accepted now in scientific treatises of grams (see). A gram is almost equal to M. of one cubic centimeter of water, at a temperature of its greatest density (at 4 ° C, M. 1 cubic cm of water \u003d 1.000013 g). According to the unit of mass, the unit of force is also determined - the dyna, or, in short, the dyna (see Units of measures). Force f, informing T grams A units of acceleration, equal to (1 dyne)× m× A = that dynam. Body weight is also determined R, in dynes, according to M. m, and free fall acceleration g; p=mg din. However, we do not have enough data for a direct comparison of the amounts of various substances, such as wood and copper, to verify whether equal M. of these substances really contain equal amounts of them. As long as we are dealing with bodies of the same substance, we can measure the amount of substance in them by their volumes, when equal. temperatures, according to the weight of bodies, according to the forces imparting equal accelerations to them, since these forces, with a uniform distribution over the body, must be proportional to the number of equal particles. This proportionality of the amount of the same substance to its weight also takes place for bodies of different temperatures, since heating does not change the weight of the body. If, however, we are dealing with bodies made of different substances (one of copper, another of wood, etc.), then we cannot assert that the quantities of matter are proportional to the volumes of these bodies, nor proportional to their forces that give them equal accelerations, since different substances could have a different ability to perceive motion, just as they have a different ability to magnetize, to absorb heat, to neutralize acids, etc. Therefore, it would be more correct to say that equal M. of various substances contain equivalent their quantity in relation to mechanical action - but indifferently in relation to other physical and chemical properties of these substances. Only under one condition is it possible to compare the quantities of dissimilar substances by their weight - this is under the condition of extending to them the concept of the relative density of bodies consisting of the same substance, but at different temperatures. To do this, it is necessary to assume that all heterogeneous substances consist of exactly the same particles, or initial elements, and that all the various physical and chemical properties of these substances are the result of a different grouping and convergence of these elements. We do not currently have enough data to confirm or deny this, although many phenomena even speak in favor of such a hypothesis. In essence, chemical phenomena do not contradict this hypothesis: many bodies consisting of different simple bodies exhibit similar physical and crystalline properties, and vice versa, bodies with the same composition of simple substances exhibit different physical and partly even chemical properties, such, for example, isomeric bodies having the same percentage of the same simple bodies, and allotropic bodies representing varieties of the same simple body (such as coal, diamond and graphite, representing different states of carbon). The force of gravity, the most general of all the forces of nature, speaks in favor of the hypothesis of the unity of matter, since it acts on all bodies in the same way. That all bodies of the same substance must fall equally rapidly, and that their weight must be proportional to the quantity of the substance, is understandable; but it by no means follows from this that bodies made of different substances also fall with the same speed, since gravity could act differently, for example, on water particles than on zinc particles, just as the magnetic force acts differently on different bodies. Observations show, however, that all bodies, without exception, in empty space at the same place on the surface of the Earth, fall equally quickly, and consequently, gravity acts on all bodies as if they consisted of the same substance and differed only by the number of particles and their distribution in a given volume. In the chemical phenomena of the union and decomposition of bodies, the sums of their weights remain unchanged; their structure and, in general, properties that do not belong to the very essence of matter are modified. The independence of gravity from the structure and composition of bodies shows that this force penetrates deeper into the essence of matter than all other forces of nature. Therefore, the measurement of the amount of matter by the weight of bodies has a complete physical basis.

P. Van der Fleet.

Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron. - St. Petersburg: Brockhaus-Efron. 1890-1907 .

See what "Body weight" is in other dictionaries:

body mass- kūno masė statusas T sritis Standartizacija ir metrologija apibrėžtis Tam tikro kūno masė. atitikmenys: engl. body mass vok. Korpermasse, f rus. body weight, fpranc. masse du corps, f … Penkiakalbis aiskinamasis metrologijos terminų žodynas

body mass- kūno masė statusas T sritis fizika atitikmenys: angl. body mass vok. Korpermasse, f rus. body weight, fpranc. masse du corps, f … Fizikos terminų žodynas

body mass- kūno masė statusas T sritis Kūno kultūra ir sportas apibrėžtis Žmogaus svoris. Kūno masė yra labai svarbus žmogaus fizinės brandos, sveikatos ir darbingumo rodiklis, vienas pagrindinių fizinio išsivystymo požymių. Kūno masė priklauso nuo amžiaus … Sporto terminų žodynas

Body mass- One of the main indicators of the level of physical development of a person, depending on age, gender, morphological and functional geno- and phenotypic features. Despite the existence of many systems for assessing “normal” M. t., the concept ... ...

- (weight) in anthropology is one of the main anthropometric features that determine physical development ... Big Encyclopedic Dictionary

In combination with other anthropometric features [body length (height) and chest circumference], an important indicator of physical development and health. It depends on gender, height, is associated with the nature of nutrition, heredity, ... ... Great Soviet Encyclopedia

- (weight), in anthropology one of the main anthropometric features that determine physical development. * * * HUMAN BODY WEIGHT HUMAN BODY WEIGHT (weight), in anthropology, one of the main anthropometric features that determine the physical ... ... encyclopedic Dictionary

- (weight), in anthropology one of the main. anthropometry, signs that determine physical. development … Natural science. encyclopedic Dictionary

Overweight- Accumulation of body weight (mainly due to adipose tissue) above normal for a given person, but before the development of obesity. In medical supervision, I. m. t. is understood to be an excess of the norm by 1–9%. The problem lies, however, in establishing ... ... Adaptive physical culture. Concise Encyclopedic Dictionary

ideal body weight- ideali kūno masė statusas T sritis Kūno kultūra ir sportas apibrėžtis Konkrečių sporto šakų, rungčių, tam tikras funkcijas komandoje atliekančių žaidėjų kūno masės modelis. atitikmenys: engl. ideal body mass vok. ideale Körpermasse, f rus.… … Sporto terminų žodynas

Books

• Health School. Overweight and obesity (+ CD-ROM), R. A. Eganyan, A. M. Kalinina. The publication includes a manual for overweight and obese health school physicians with an appendix on CD-ROM and materials for patients. In the guide for…