Nm is a unit of measurement in physics. Just about something complicated: a nanometer is actually how much

; designations: mmk, mμ)

It is one of the most commonly used units of measurement for short lengths, and is equal to 10 angstroms, a generally accepted non-SI unit of measurement. It is often associated with the field of nanotechnology and the wavelength of visible light.

One nanometer is approximately equal to a conventional structure of ten hydrogen atoms lined up, if we take two Bohr radii as the diameter of a hydrogen atom.

The distance between carbon atoms in diamond is 0.154 nm.

See also

Notes

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See what “Nanometer” is in other dictionaries:

Nanometer... Spelling dictionary-reference book

Nanometer (nm) is a unit of length equal to 10–9 m, 10–3 μm, or 10 angstroms (A). (Source: “Microbiology: a dictionary of terms”, Firsov N.N., M: Drofa, 2006) Nanometer (nm) units. length measurements equal to 10"9m. (Source: “Dictionary of terms... ... Dictionary of microbiology

- (designation nm), a unit of length equal to 10 9 m. Used to measure intermolecular distances and wavelengths. Replaced the ANGSTREM unit previously used for such measurements... Scientific and technical encyclopedic dictionary

Exist., number of synonyms: 2 unit (830) millimicron (2) ASIS Dictionary of Synonyms. V.N. Trishin. 2013… Dictionary of synonyms

nanometer- a, m. nanomètre m. One billionth of a meter. The thinnest wires with a diameter of less than ten nanometers (thousandths of a micron) have been created at Harvard University (USA). Such a wire consists of only 20 rows of atoms. Nizh 1999 9 17. Kilometers,… … Historical Dictionary of Gallicisms of the Russian Language

nanometer- millimicron (10 9 meters) Topics of biotechnology Synonyms millimicron EN nanometer ... Technical Translator's Guide

Nanometer nm- Nanometer, nm * nanometer, nm * nanometer or nm unit of length equal to 10 E, or 10 9 m ... Genetics. Encyclopedic Dictionary

The term nanometer The term in English nanometer Synonyms Abbreviations nm, nm Related terms nano, nanorange Definition one billionth of a meter. Description is a generally accepted unit of measurement of length in the field of nanomaterials and nanotechnologies.… … Encyclopedic Dictionary of Nanotechnology

nanometer- Nanometer (nm) Nanometer (nm) A unit of length equal to one billionth (10 9) of a meter. Commonly used to measure the size of atoms, molecules and cellular organelles. The size of a silicon atom is 0.24 nm. The diameter of a human hair is about... ... Explanatory English-Russian dictionary on nanotechnology. - M.

nanometer- nanometras statusas T sritis Standartizacija ir metrologija apibrėžtis Dalinis ilgio matavimo vienetas, 10⁹ karto mažesnis už metrą: 1 nm = 10⁻⁹ m. atitikmenys: engl. nanometer; nanometer vok. Nanometer, n rus. nanometer, m pranc. nanometre, m... Penkiakalbis aiškinamasis metrologijos terminų žodynas

So, “micro” means so much. These pages contain unit converters that allow you to quickly and accurately convert values ​​from one unit to another, as well as from one system of units to another. How do I feel about this? I already know what a meter is. I found a centimeter and a millimeter on a ruler. How much do “micro” and “nano” mean?

One billionth of a meter. The thinnest wires with a diameter of less than ten nanometers (thousandths of a micron) have been created at Harvard University (USA). The definition of these units is in no way connected with any historical human constructions, only with the fundamental laws of nature.

Nanometer. Unit converter.

Since then, all other measures have also been redefined in terms of metric units. And in 1996, the first version of the site with instant calculations was launched. In the SI system, length is measured in meters. Derived units such as kilometer (1000 meters) and centimeter (1/100 meter) are also commonly used in the metric system. Shipping uses nautical miles. One nautical mile is equal to 1852 meters. This made latitude calculations easier, since 60 nautical miles equaled one degree of latitude.

In astronomy they measure long distances, therefore, to facilitate calculations, special values ​​have been adopted. An astronomical unit (au, au) is equal to 149,597,870,700 meters. This is the distance that light travels in a vacuum in one Julian year. This quantity is used in popular science literature more often than in physics and astronomy. One parsec is the distance from the Sun to another astronomical object, such as a planet, star, moon, or asteroid, with an angle of one arcsecond.

Distance in astronomy

This is the distance a person travels in an hour. Sea League - three nautical miles, approximately 5.6 kilometers. Elbow is an ancient measurement equal to the distance from the tip of the middle finger to the elbow. This value was widespread in the ancient world, in the Middle Ages, and until modern times. The meter was later equated to the wavelength of the orange line of the electromagnetic spectrum of the krypton ⁸⁶Kr atom in a vacuum, multiplied by 1,650,763.73.

Distance in physics and biology

In physics, length is always a positive scalar quantity. Given the speed of a wheel or its radius, the distance traveled by that wheel can be calculated. Such calculations are useful, for example, in cycling. Calculations for converting units in the Length and Distance converter are performed using the functions of unitconversion.org.

Convert feet and inches to meters and vice versa

Select the unit to convert to from the right list of units. Compared to 22 nm, 14 nm technology reduces the distance between dielectric fins, increases the height of the barriers, and reduces their number. Thus, Intel Core in its mobile form it is getting closer and closer to the SoC design, and there is no doubt that it will soon get very close.

Using the Length and Distance Converter

Perhaps this is a way to lure people to new hardware, since Android with every new version on the contrary, it accelerates on the same hardware. Or maybe programming shouldn't be such a simple profession, accessible to those who don't want to lick. It's time to move the distribution of labor to a new level, as is done in cinema: a book should have a producer, director, screenwriter, costume designers, special effects masters, etc.

Such a wire consists of only 20 rows of atoms. The international nautical mile was defined in 1929 at the International Extraordinary Hydrographic Conference. In physics, natural units of measurement are based only on fundamental physical constants.

Currently, the only non-metric measures of length that are officially allowed to be used are miles, yards and feet for road signs. Cruise ship Celebrity Reflection in port in Miami. It was originally measured as an arc of one minute along the meridian, that is, 1/(60x180) of the meridian. The value of one astronomical unit is a constant, that is, a constant value. The Earth is located at a distance of one astronomical unit from the Sun.

For this purpose, a special value has been adopted, the micrometer. The result will immediately appear in the “Result” field and in the “Converted Value” field. Nanometer - (nm, nm) a unit of length in the metric system, equal to one billionth of a meter (i.e. 10−9 meters).

The science of weights and measures, metrology is yesterday. Today it is common to measure what no one sees, that is, nano-sized objects. This is what nanometrology does. Stepan Lisovsky, MIPT graduate student, employee of the Department of Nanometrology and Nanomaterials, talks about the basic principles of nanometrology and the functions of various microscopes and explains why the size of a particle depends on the method of its measurement.

Reference Thinking

To begin with, let's talk about simple metrology. As a discipline, it could have arisen in ancient times, when many people talked about measure - from Pythagoras to Aristotle - but it did not arise. Metrology failed to become part of the scientific picture of the world of that time because of the same Aristotle. For many centuries to come, he established the priority of a qualitative description of phenomena over a quantitative one. Everything changed only in the time of Newton. The meaning of phenomena “according to Aristotle” ceased to satisfy scientists, and the emphasis shifted - from the semantic part of the description to the syntactic one. Simply put, it was decided to look at the measure and degree of interactions of things, and not try to comprehend their very essence. And it turned out to be much more fruitful. Then came the finest hour of metrology.

The most important task of metrology is to ensure the uniformity of measurements. The main goal is to decouple the measurement result from all details: time, place of measurement, who is measuring and how he decides to do it today. As a result, only that should remain that always and everywhere, regardless of anything, will belong to the thing - its objective measure, which belongs to it due to the reality that is common to all. How to get to things? Through its interaction with the measuring device. To do this, there must be a unified measurement method, as well as a standard that is the same for everyone.

So, we have learned to measure - all that remains is for everyone else in the world to measure the same way as we do. This requires that they all use the same method and use the same standards. Practical benefits People quickly realized the introduction of a uniform system of measures for everyone and agreed to start negotiating. Appeared metric system measurements, which gradually spread to almost the entire world. In Russia, by the way, the credit for introducing metrological support belongs to Dmitry Mendeleev.

The result of a measurement, in addition to the actual value of the quantity, is also an approach expressed in units of measurement. Thus, a measured meter will never become a newton, and an ohm will never become a tesla. That is, different quantities imply a different nature of measurement, but, of course, this does not always happen. A meter of wire turns out to be a meter both from the point of view of its spatial characteristics, and from the point of view of conductivity, and from the point of view of the mass of the substance in it. One quantity turns out to be involved in different phenomena, and this greatly facilitates the work of the metrologist. To a certain extent, even energy and mass turned out to be equivalent, so the mass of supermassive particles is measured in the energy required to create it.

In addition to the meaning of a quantity and its unit of measurement, there are several other important factors that you need to know about each measurement. All of them are contained in a specific measurement technique chosen for the case we need. It specifies everything: standard samples, the accuracy class of instruments, and even the qualifications of researchers. Being able to provide all this, based on the methodology, we can carry out correct measurements. Ultimately, the use of the technique gives us guaranteed measurements of the measurement error, and the entire measurement result comes down to two numbers: the value and its error, with which scientists usually work.

Measure the invisible

Nanometrology works according to almost the same laws. But there are a couple of nuances that cannot be ignored. To understand them, you need to understand the processes of the nanoworld and understand what, in fact, is their peculiarity. In other words, what is so special about nanotechnology?

Of course, we need to start with the size: one nanometer in a meter is approximately the same as one Chinese in the population of China. Dimensions of this scale (less than 100 nm) make a whole series of new effects possible. Here are the effects of quantum physics, including tunneling, and interaction with molecular systems, and biological activity and compatibility, and an overdeveloped surface, the volume of which (more precisely, the near-surface layer) is comparable to the total volume of the nanoobject itself. Such properties are a treasure trove of opportunities for a nanotechnologist and at the same time a curse for a nanometrologist. Why?

The fact is that, due to the presence of special effects, nanoobjects require completely new approaches. They cannot be seen optically in the classical sense due to a fundamental limitation on the resolution that can be achieved. Because it is strictly tied to the wavelength of visible radiation (you can use interference and so on, but all this is already exotic). Several basic solutions have been invented for this problem.

It all started with a field-electronic projector (1936), which was later modified into a field-ionic one (1951). The principle of its operation is based on the rectilinear movement of electrons and ions under the action of an electrostatic force directed from the nano-sized cathode to the anode-screen of the macroscopic dimensions we already need. The picture that we see on the screen is formed at or near the cathode due to certain physical and chemical processes. First of all, this is the extraction of field electrons from the atomic structure of the cathode and the polarization of atoms of the “imaging” gas near the cathode needle. Once formed, a picture in the form of a certain distribution of ions or electrons is projected onto the screen, where it is manifested by fluorescence forces. This is an elegant way to look at the nanostructure of spikes made from some metals and semiconductors, but the elegance of the solution is too restrictive on what we can see, so such projectors have not become particularly popular.

Another solution was to literally feel the surface, first implemented in 1981 in the form of a scanning probe microscope, which was awarded the Nobel Prize in 1986. As you can guess from the name, the surface under study is scanned with a probe, which is a pointed needle.

An interaction occurs between the needle and the surface structure, which can be determined with high accuracy either by the force acting on the probe, by the resulting deflection of the probe, or by a change in the frequency (phase, amplitude) of the probe oscillations. The initial interaction, which determines the ability to study almost any object, that is, the universality of the method, is based on the repulsive force that arises upon contact and on long-range van der Waals forces. It is possible to use other forces, and even the emerging tunnel current, mapping the surface not only from the point of view of the spatial location of nanoobjects on the surface, but also their other properties. It is important that the probe itself be nanosized, otherwise it will not be the probe that scans the surface, but the surface - the probe (due to Newton’s third law, the interaction is determined by both objects and in a sense symmetrically). But in general, this method turned out to be both universal and possessing the widest range of capabilities, so that it became one of the main ones in the study of nanostructures. Its main disadvantage is that it is extremely time-consuming, especially in comparison with electron microscopes.

Electron microscopes, by the way, are also probe microscopes, only the probe in them is a focused beam of electrons. The use of a lens system makes it conceptually similar to optical, although not without major differences. First and foremost: an electron has a shorter wavelength than a photon due to its massiveness. Of course, the wavelengths here do not belong to the electron and photon particles themselves, but characterize the behavior of the waves corresponding to them. Other important difference: the interaction of bodies with photons and with electrons is quite different, although it is not without common features. In some cases, the information obtained from interaction with electrons is even more meaningful than from interaction with light - however, the opposite situation is not uncommon.

And the last thing you should pay attention to is the difference between optical systems: if for light the lenses are traditionally material bodies, then for electron beams they are electromagnetic fields, which gives greater freedom to manipulate electrons. This is the “secret” of scanning electron microscopes, the image on which, although it looks like it was obtained with a regular light microscope, is made this way only for the convenience of the operator, and is obtained from a computer analysis of the characteristics of the interaction of the electron beam with a separate raster (pixel) on samples that are scanned sequentially. The interaction of electrons with a body makes it possible to map the surface in terms of relief, chemical composition and even luminescent properties. Electron beams can pass through thin samples, which allows one to see the internal structure of such objects - right down to the atomic layers.

These are the main methods that allow us to distinguish and study the geometry of objects at the nanoscale level. There are others, but they work with entire systems of nanoobjects, calculating their parameters statistically. Here is X-ray diffractometry of powders, which makes it possible to find out not only the phase composition of the powder, but also something about the size distribution of crystals; and ellipsometry, which characterizes the thickness of thin films (a thing that is indispensable in the creation of electronics, in which the architecture of systems is created mainly layer by layer); and gas sorption methods for analyzing specific surface area. The names of some methods can be confusing: dynamic light scattering, electroacoustic spectroscopy, nuclear magnetic resonance relaxometry (it is, however, simply called NMR relaxometry).

But that's not all. For example, you can transfer a charge to a nanoparticle moving in the air, then turn on the electrostatic field and, looking at how the particle deviates, calculate its aerodynamic size (its friction force with the air depends on the size of the particle). By the way, the size of nanoparticles is determined in a similar way in the already mentioned method of dynamic light scattering, only the speed in Brownian motion is analyzed, and also indirectly, by fluctuations of light scattering. The hydrodynamic diameter of the particle is obtained. And there are more than one such “cunning” methods.

Such an abundance of methods that seem to measure the same thing - size, has one interesting detail. The size of the same nanoobject often differs, sometimes even by several times.

What size is right?

Here is the time to remember ordinary metrology: the measurement results, in addition to the actual measured value, are also determined by the accuracy of the measurements and the method by which the measurement was carried out. Accordingly, the difference in results can be explained both by different accuracy and by the different nature of the measured quantities. The thesis about the different nature of different sizes of the same nanoparticle may seem wild, but it is true. The size of a nanoparticle in terms of its behavior in an aqueous dispersion is not the same as its size in terms of the adsorption of gases on its surface and is not the same as its size in terms of interaction with an electron beam in a microscope. Not to mention that for statistical methods and one cannot talk about a certain size, but only about a value that characterizes the size. But despite these differences (or even thanks to them), all these results can be considered equally true, simply saying a little about different things, looking from different sides. These results can be compared only from the point of view of the adequacy of relying on them in certain situations: to predict the behavior of a nanoparticle in a liquid, it is more adequate to use the value of the hydrodynamic diameter, and so on.

All of the above is true for ordinary metrology, and even for any recording of facts, but it is often overlooked. We can say that there are no facts that are more true and less true, more consistent with reality and less (except perhaps forgery), but there are only facts that are more and less adequate for use in a given situation, and also based on more or less correct interpretation for this. Philosophers have learned this well since the times of positivism: any fact is theoretically loaded.

Don't miss Stepan's lecture:

Modern engine: power or torque?

For more than a century, internal combustion engines have been used in almost all areas of transport. They are the “heart” of a car, tractor, diesel locomotive, ship, airplane, and over the past thirty years they have come to represent a kind of fusion of the latest achievements of science and technology. Terms such as POWER and TORQUE have become familiar to us and are a necessary criterion for assessing the power capabilities of an engine. But how accurately can you assess the potential of an engine, having only meager figures with the technical data of the car in front of your eyes? I hope you will not rely entirely on the assurances of the car dealership salesperson that the engine of the car you are purchasing is powerful enough and will completely satisfy you? In order not to regret later about an unprofitable purchase, I ask you to familiarize yourself with the following.
Since ancient times, humanity has used all kinds of mechanisms and devices for construction, moving goods, and transporting people. With the invention of HIS MAJESTY'S WHEEL more than 10 thousand years ago, the theory of mechanics underwent major changes. Initially, the role of the wheel was reduced only to a banal reduction of resistance (friction force) and the transfer of friction force into rolling. Of course, rolling a round one is much more pleasant than dragging a square one! But a qualitative change in the method of using the wheel occurred much later thanks to the advent of another ingenious invention - the ENGINE! The father of the steam locomotive is often called George Stevenson, who built his famous steam locomotive "Rocket" in 1829. But back in 1808, the Englishman Richard Trevithick demonstrates one of the most revolutionary inventions in history - the first steam locomotive. But to our general joy, Trevithick first built a steam car for street traffic, and then only came up with the idea of ​​a steam locomotive. Thus, the car is in some way the progenitor of the steam locomotive. Unfortunately, the fate of the discoverer Richard Trevithick, as well as many engineers, but not businessmen, was sad. He went broke, lived for a long time in a foreign land, and died in poverty. But let's not talk about sad things...
Our task is to understand what engine torque and power are, and it will be greatly simplified if we remember the structure of a steam locomotive. In addition to the passive converter of friction from one type to another, the wheel began to perform one more task - to create a driving (traction) force, that is, pushing off from the road, setting the carriage in motion. The steam pressure acts on the piston, which in turn presses on the connecting rod, which turns the wheel, creating TORQUE. The rotation of the wheel under the influence of torque causes the appearance of a couple of forces. One of them - the frictional force between the rail and the wheel - is, as it were, pushed back from the rail, and the second - the same TRACTION FORCE we are looking for is transmitted through the wheel axis to the parts of the locomotive frame. Using the example of a steam locomotive, it is noticeable that the greater the steam pressure acting on the piston, and through it on the connecting rod, the greater the traction force will push it forward. Obviously, by changing the steam pressure, the diameter of the wheel and the position of the connecting rod attachment point relative to the center of the wheel, you can change the power and speed of the locomotive. The same thing happens in a car.

The difference is that all force transformations are carried out directly in the engine itself. At the exit from it we simply have a rotating shaft, that is, instead of a force pushing the locomotive forward, here we get a circular motion of the shaft with a certain force - TORQUE. And the POWER developed by an engine is its ability to rotate as quickly as possible, while simultaneously creating torque on the shaft. Then the car’s power transmission (transmission) comes into action, which changes this torque as we need and delivers it to the drive wheels. And only in contact between the wheel and the road surface is the torque “straightened out” again and becomes a traction force.
Obviously, it is preferable to have the greatest traction force. This will provide the required acceleration intensity, the ability to climb hills and transport more people and cargo.

IN technical specifications car has such parameters as engine speed at maximum power and maximum torque and the magnitude of this power and torque. As a rule, they are measured in revolutions per minute (min), kilowatts (kW) and newtonometers (Nm), respectively. It is necessary to be able to correctly understand the external speed characteristics of the engine.

This graphic image dependence of power and torque on crankshaft speed. It's the shape of the torque curve that's most telling, not the magnitude. The sooner the maximum is reached and the more flat the curve drops as the speed increases (that is, the engine has constant thrust), the more correctly the engine is designed and operates. However, getting an engine with sufficient power reserves, high speeds and even stable TORQUE over a wide speed range is not easy. This is precisely what the use of supercharging of various systems, electronic control of fuel injection, variable valve timing, adjustment of the exhaust system and a number of other measures are aimed at.
Let's look at an example. You have to overcome a rise, and you cannot increase the speed (accelerate the car before the rise) due to the road situation. To maintain the pace of movement, you will need to increase the traction force. Here a situation often arises that looks like this: adding gas does not increase the traction force. This causes a decrease in speed, and hence engine speed, accompanied by a further decrease in the traction force on the drive wheels.
So what to do? How to maintain high traction force at low speeds if the engine “does not pull”, that is, does not provide sufficient TORQUE? The transmission comes into action. You manually, or the automatic transmission yourself, change the gear ratio so that the traction force and the speed of movement are in the optimal ratio. But this is an additional inconvenience in driving a car. The conclusion suggests itself: it would be better if the engine itself adapted to work in such situations. For example, you are driving uphill. The force of resistance to the movement of the car increases, the speed decreases, but the traction force can be added by simply pressing the gas pedal harder. Automotive designers use the term “ENGINE ELASTICITY” to evaluate this parameter.
This is the ratio between the maximum power rpm and the maximum torque rpm (rpm Pmax/rpm Mmax). It should be such that, in relation to the maximum power speed, the maximum torque speed is as low as possible. This will allow you to reduce and increase speed only by operating the gas pedal, without resorting to changing gears, as well as driving in higher gears at low speed. You can practically evaluate the elasticity of the engine by checking the car’s ability to accelerate from 60 to 100 km/h in fourth gear. The less time this acceleration takes, the more elastic the engine.
To confirm the above, let us turn to the results of tests of Audi, BMW and Mercedes cars conducted in Europe and published by the Russian publishing house of the German magazine Auto Motor und Sport in the November 2005 issue. Mainly, let's look at the characteristics of Audi and BMW. From the table above it is clear that the Audi engine, of a much smaller volume and almost the same power, is practically not inferior to the Bavarian in acceleration from a standstill, but in measurements of elasticity and efficiency it beats the competitor on both blades. Why is this happening? Because the elasticity coefficient of the Audi engine is 2.39 (4300/1800) versus 1.66 (5800/3500) for BMW, and since the weight of the cars is approximately equal, the stallion from Munich allows him to give an enviable head start to his compatriot. Moreover, these impressive results are achieved using AI-95 fuel.
So, let's sum it up!
Of two engines of the same volume and power, the one with higher elasticity is preferable. All other things being equal, such a motor will wear out less, operate with less noise and consume less fuel, and will also simplify manipulation of the gear lever. Modern supercharged gasoline and diesel engines fall under all these conditions. Operating a car with such an engine, you will get a lot of pleasant impressions!

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1 newton meter [N m] = 0.1019716212978 kilogram-force meter [kgf m]

Initial value

Converted value

newton meter kilonewton meter millinewton meter micronewton meter ton-force (short)-meter ton-force (long)-meter ton-force (metric)-meter kilogram-force meter gram-force centimeter pound-force foot poundal-foot poundal-inch

More about moment of force and terminology

General information

A moment of force is a physical quantity that characterizes how much force applied to a body causes the body to rotate around an axis. In English and some other languages, this phenomenon is called by different words, depending on the context. Since this article was written for a translator site, we will talk a little about terminology in other languages. The magnitude of the moment of force is equal to the vector product of the force applied to the body by the distance calculated along the perpendicular between the axis of rotation and the point of application of the force that causes rotation. IN English For the moment of force, two terms are used, moment of force ( moment of force) and a separate term, torque. The English term torque is used to denote a physical quantity that is measured in the same way as the moment of force (in English), but only in a context in which the force responsible for this property necessarily causes rotation bodies. This quantity is also measured by multiplying the force by the distance between the axis of rotation and the point of application of the force. In Russian, the term “torque” corresponds to the terms “torque” and “rotational moment”, which are synonyms. The Russian term "torque" refers to the internal forces that occur in objects under the influence of loads applied to them. This term corresponds to the English terms “torsional movement”, “torque effect”, “torsional shear” and some others.

As mentioned above, in this article we pay a lot of attention to the context in which a particular English term is used. Our task is to explain the difference to help the reader if he encounters these terms in an English text in the future. The most important thing to remember is that both terms, moment of force and torque, are used for the same physical quantity, but in different contexts. In many languages, like in Russian, only one term is used. Below we will consider in what context each of these terms is used.

Terminology in English

As we mentioned above, the English terms “torque” and “torque” are used for the same concept, but in different contexts. In this section we will discuss when in English the term “torque” is most often used and when “torque” is almost never used. The concept of “torque” is often spoken of in the context when a force acting on a body causes a change in the angular acceleration of the body. On the other hand, when we talk about a moment of force in English, the force acting on the body does not necessarily cause such acceleration. That is, “torque” is a particular example of a moment of force, but not vice versa. You can also say that "torque" is a moment of force, but a moment of force is not "torque".

Let's look at a few examples below. It is worth recalling once again that the difference in the use of these two terms depends on the context, but they are used for the same physical phenomenon. Often these two terms are used interchangeably.

To understand what a moment of force is, let’s first consider what a moment is in general. Moment- this is the intensity with which a force acts on a body at a certain distance relative to the body. The magnitude of the moment of force depends on the magnitude of the force that acts on the body and on the distance from the point of application of the force to a point on the body. As we saw from the definition above, this point is often located on the axis of rotation.

The moment of force is proportional to the force and the radius. This means that if a force is applied to a body at a certain distance from the axis of rotation, then the rotational effect of this force is multiplied by the radius, that is, the further from the axis of rotation the force is applied, the more rotating effect it has on the body. This principle is used in systems of levers, gears and pulleys to obtain gains in force. In this context, people most often talk about the moment of force and its use in various systems, such as lever systems. Examples of lever operation are shown in. It is worth noting that in this article we are mainly discussing torque, which corresponds to the English term “torque”.

Sometimes the concepts of moment of force and torque are distinguished using the concept of “force pair”. Couple of forces- these are two forces of the same magnitude acting in opposite directions. These forces cause the body to rotate, and their vector sum is zero. That is, the term “moment of force” is used in a more general context than torque.

In some cases, the term "torque" is used when the body is rotating, while the term "moment" is used when the body is not rotating, for example, when talking about support beams and other structural elements of buildings in construction. In such systems, the ends of the beam are either rigidly fixed (rigid termination) or the fastening allows the beam to rotate. In the second case, they say that this beam is fixed on a hinged support. If a force acts on this beam, for example, perpendicular to its surface, then the result is a moment of force. If the beam is not fixed, but is attached to a hinged support, then it moves freely in response to the forces acting on it. If the beam is fixed, then in opposition to the moment of force another moment is formed, known as bending moment. As you can see from this example, the terms moment of force and torque differ in that moment of force does not necessarily change angular acceleration. In this example, the angular acceleration does not change because the external forces acting on the beam are countered by internal forces.

Examples of moment of force

A good example of a moment of force in everyday life is the action on the body of both a moment of force and a bending moment, which we talked about above. The moment of force is often used in construction and in the design of building structures, since, knowing the moment of force, it is possible to determine the load that this structure must withstand. The load includes the load caused by self-weight, the load caused by external influences (wind, snow, rain, etc.), the load caused by furniture, and the load caused by visitors and building occupants (their weight). The load caused by people and the interior is called in construction payload, and the load caused by the weight of the building itself and the environment is called static or constant load.

When the Alexandra Bridge over the Ottawa River was built in 1900, many I-beams were used

If a force is applied to a beam or other structural element, then in response to this force a bending moment occurs, under the influence of which some parts of this beam are compressed, while others, on the contrary, are stretched. Consider, for example, a beam that is subject to a downward force applied centrally. Under the influence of this force, the beam takes a concave shape. Upper part the beam on which the force acts is compressed under the influence of this force, while the lower one, on the contrary, is stretched. If the load is greater than this material can withstand, the beam collapses.

The greatest load is on the very top and bottom layers of the beam, so in construction and in the design of structures these layers are often strengthened. A good example is using I-beam structures. I-beam - a structural element with a cross section in the shape of the letter H or Latin letter “I” with top and bottom serifs (that’s why English people use the term I-beam, This form is very economical, since it allows you to strengthen the weakest parts of the beam, using the least amount of material. Most often, I-beams are made of steel, but other materials can be used for a strong I-beam design. You can find videos on YouTube testing I-beams made from materials less strong than steel, such as foam and plywood (search for plywood beam test). I-beams made of plywood and particle boards appeared on Russian market building materials are relatively new, although they have long been widely used in the construction of frame houses in North America.

If the structure is subject to a bending moment, then I-beams are a solution to strength problems. I-beams are also used in structures that are subject to shear stress. The edges of the I-beam resist the bending moment while the center support resists the shear stress. Despite its advantages, an I-beam cannot withstand. To reduce this stress on the surface of the structure, it is made round and the surface is polished to prevent stress from accumulating at points where the surface is uneven. Increasing the diameter and making this structure hollow inside can help reduce its weight.

Conclusion

In this article, we looked at the difference between the terms “moment of force” and “torque,” ​​as well as the English terms “moment of force” and “torque,” ​​and saw several examples of moment of force. We mainly talked about cases where the moment of force creates problems in construction, but often the opposite happens and the moment of force brings benefits. Examples of using moment of force in practice - in. It is also worth mentioning that the difference in terminology in English is often significant in American and British engineering and civil engineering, while in physics these terms are often used interchangeably.

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