Physics, as a science that studies the laws of our Universe, uses a standard research methodology and a certain system of units of measurement. it is customary to denote H (Newton). What is strength, how to find and measure it? Let's explore this issue in more detail.

Isaac Newton is an outstanding English scientist of the 17th century who made an invaluable contribution to the development of the exact mathematical sciences. It is he who is the forefather of classical physics. He managed to describe the laws that govern both huge celestial bodies and small grains of sand carried away by the wind. One of his main discoveries is the law of gravity and the three basic laws of mechanics, which describe the interaction of bodies in nature. Later, other scientists were able to deduce the laws of friction, rest and sliding only thanks to the scientific discoveries of Isaac Newton.

A bit of theory

In honor of the scientist, a physical quantity was named. Newton is a unit of measure for force. The very definition of force can be described as follows: "force is a quantitative measure of the interaction between bodies, or a quantity that characterizes the degree of intensity or tension of bodies."

The magnitude of the force is measured in newtons for a reason. It was this scientist who created three unshakable "power" laws that are relevant to this day. Let's explore them with examples.

First law

For a complete understanding of the questions: "What is Newton?", "The unit of measurement of what?" and "What is its physical meaning?"

The first says that if other bodies do not exert any influence on the body, then it will be at rest. And if the body was in motion, then in the complete absence of any action on it, it will continue its uniform movement in a straight line.

Imagine that there is a book with a certain mass on the flat surface of the table. Having designated all the forces acting on it, we get that this is the force of gravity, which is directed vertically downward, and (in this case, the table), directed vertically upward. Since both forces balance each other's actions, the value of the resultant force is zero. According to Newton's first law, it is for this reason that the book is at rest.

Second law

He describes the relationship between the force acting on the body and the acceleration that it receives as a result of the applied force. Isaac Newton, when formulating this law, was the first to use a constant mass as a measure of the manifestation of inertia and inertia of a body. Inertia is the ability or property of bodies to maintain their original position, that is, to resist external influences.

The second law is often described by the following formula: F = a * m; where F is the resultant of all forces applied to the body, a is the acceleration received by the body, and m is the mass of the body. The force is ultimately expressed in kg * m / s 2. This expression is usually denoted in newtons.

What is Newton in physics, what is the definition of acceleration and how is it related to force? These questions are answered by the formula of the second law of mechanics. It should be understood that this law works only for those bodies that move at speeds much lower than the speed of light. At values ​​of speeds close to the speed of light, slightly different laws, adapted by a special section of physics on the theory of relativity, work.

Newton's third law

This is perhaps the clearest and simplest law that describes the interaction of two bodies. He says that all forces arise in pairs, that is, if one body acts on another with a certain force, then the second body, in turn, also acts on the first with a force equal in magnitude.

The very formulation of the law to scientists is as follows: "... the interactions of two bodies on each other are equal to each other, but at the same time directed in opposite directions."

Let's see what Newton is. In physics, it is customary to consider everything in terms of specific phenomena, therefore, we will give several examples describing the laws of mechanics.

1. Aquatic animals such as ducks, fish or frogs move in or through water precisely because of their interaction with it. Newton's third law says that when one body acts on another, there is always a reaction, which is equivalent in strength to the first, but directed in the opposite direction. Based on this, we can conclude that the movement of ducks occurs due to the fact that they push the water back with their paws, and they themselves swim forward due to the reciprocal action of the water.
2. The squirrel wheel is a prime example of proof of Newton's third law. Everyone probably knows what a squirrel wheel is. This is a fairly simple design, reminiscent of both a wheel and a drum. It is installed in cages so that pets like squirrels or decorative rats can run. The interaction of two bodies, a wheel and an animal, causes both of these bodies to move. Moreover, when the squirrel runs fast, the wheel spins at high speed, and when it slows down, the wheel starts spinning more slowly. This proves once again that action and response are always equal, although directed in opposite directions.
3. Everything that moves on our planet moves only thanks to the "reciprocal action" of the Earth. It may sound strange, but in fact, when we walk, we only make an effort to push the ground or any other surface. And we are moving forward, because the earth pushes us in response.

What is Newton: a unit of measurement or a physical quantity?

The very definition of "newton" can be described as follows: "it is a unit of measure of force." And what is its physical meaning? So, based on Newton's second law, this is a derived quantity, which is defined as a force capable of changing the speed of a body weighing 1 kg by 1 m / s in just 1 second. It turns out that Newton is, that is, it has its own direction. When we apply force to an object, for example pushing a door, then we simultaneously set the direction of movement, which, according to the second law, will be the same as the direction of the force.

If you follow the formula, it turns out that 1 Newton = 1 kg * m / s 2. When solving various problems in mechanics, it is very often required to translate newtons into other quantities. For convenience, when finding certain values, it is recommended to remember the basic identities that connect Newtons with other units:

• 1 N = 10 5 dyne (dyne is a unit of measurement in the CGS system);
• 1 N = 0.1 kgf (kilogram-force is a unit of force in the ICGSS system);
• 1 N = 10 -3 walls (the unit of measurement in the MTS system, 1 walls is equal to the force that imparts an acceleration of 1 m / s 2 to any body weighing 1 ton).

The law of universal gravitation

One of the most important discoveries of the scientist, which turned the idea of ​​our planet, is Newton's law of gravitation (what is gravitation, read below). Of course, before him there were attempts to unravel the mystery of the Earth's attraction. For example, he was the first to suggest that not only the Earth has an attractive force, but also the bodies themselves are capable of attracting the Earth.

However, only Newton was able to mathematically prove the relationship between the force of gravity and the law of motion of the planets. After many experiments, the scientist realized that in fact not only the Earth attracts objects to itself, but all bodies are magnetized to each other. He derived the law of gravity, which states that any bodies, including celestial bodies, are attracted with a force equal to the product of G (gravitational constant) and the masses of both bodies m 1 * m 2, divided by R 2 (the square of the distance between bodies).

All the laws and formulas derived by Newton made it possible to create an integral mathematical model, which is still used in research not only on the surface of the Earth, but also far beyond the borders of our planet.

Unit conversion

When solving problems, one should remember about the standard ones, which are also used for "Newtonian" units of measurement. For example, in problems about space objects, where the masses of bodies are large, it is often necessary to simplify large values ​​to smaller ones. If the solution turns out to be 5000 N, then it will be more convenient to write the answer in the form of 5 kN (kilo Newton). There are two types of such units: multiples and fractional ones. Here are the most used ones: 10 2 N = 1 hectoNewton (rN); 10 3 N = 1 kiloNewton (kN); 10 6 N = 1 megaNewton (MN) and 10 -2 N = 1 centiNewton (cN); 10 -3 N = 1 milliNewton (mN); 10 -9 N = 1 nanoNewton (nN).

It's no secret that there are special designations for quantities in any science. Letter designations in physics prove that this science is no exception in terms of identifying quantities using special symbols. There are a lot of basic quantities, as well as their derivatives, each of which has its own symbol. So, letter designations in physics are discussed in detail in this article.

Physics and basic physical quantities

Thanks to Aristotle, the word physics began to be used, since it was he who first used this term, which at that time was considered synonymous with the term philosophy. This is due to the generality of the object of study - the laws of the Universe, more specifically - how it functions. As you know, in the XVI-XVII centuries the first scientific revolution took place, it was thanks to it that physics was singled out as an independent science.

Mikhail Vasilievich Lomonosov introduced the word physics into the Russian language by publishing a textbook translated from German - the first physics textbook in Russia.

So, physics is a section of natural science devoted to the study of the general laws of nature, as well as matter, its movement and structure. There are not so many basic physical quantities as it might seem at first glance - there are only 7 of them:

• length,
• weight,
• time,
• current strength,
• temperature,
• amount of substance
• the power of light.

Of course, they have their own letter designations in physics. For example, the symbol m is chosen for the mass, and the symbol T for the temperature. Also, all quantities have their own unit of measurement: the intensity of light is candela (cd), and the unit of measurement for the amount of substance is the mole.

Derived physical quantities

There are much more derived physical quantities than basic ones. There are 26 of them, and often some of them are attributed to the main ones.

So, area is a derivative of length, volume - also of length, speed - of time, length, and acceleration, in turn, characterizes the rate of change in speed. Momentum is expressed in terms of mass and speed, force is the product of mass and acceleration, mechanical work depends on force and length, energy is proportional to mass. Power, pressure, density, surface density, linear density, amount of heat, voltage, electrical resistance, magnetic flux, moment of inertia, moment of momentum, moment of force - they all depend on mass. Frequency, angular velocity, angular acceleration are inversely proportional to time, and the electric charge has a direct dependence on time. The angle and solid angle are derived from length.

What letter denotes stress in physics? Voltage, which is a scalar quantity, is denoted by the letter U. For speed, the designation has the form of the letter v, for mechanical work - A, and for energy - E. The electric charge is usually denoted by the letter q, and the magnetic flux - F.

SI: general information

The International System of Units (SI) is a system of physical units that is based on the International System of Units, including the names and designations of physical quantities. It was adopted by the General Conference on Weights and Measures. It is this system that regulates the letter designations in physics, as well as their dimensions and units of measurement. The letters of the Latin alphabet are used for designation, in some cases - the Greek. It is also possible to use special characters as a designation.

Conclusion

So, in any scientific discipline there are special designations for various kinds of quantities. Naturally, physics is no exception. There are a lot of letter designations: force, area, mass, acceleration, tension, etc. They have their own designations. There is a special system called the International System of Units. It is believed that basic units cannot be mathematically derived from others. Derivative quantities are obtained by multiplying and dividing from the basic ones.

Newton (symbol: N, N) is the SI unit of force. 1 newton is equal to the force imparting an acceleration of 1 m / s² to a body with a mass of 1 kg in the direction of the action of the force. Thus, 1 N = 1 kg · m / s². The unit is named after the English physicist Isaac ... ... Wikipedia

Siemens (symbol: Cm, S) is the SI unit for measuring electrical conductivity, the reciprocal of ohm. Before World War II (in the USSR until the 1960s), Siemens was a unit of electrical resistance corresponding to resistance ... Wikipedia

This term has other meanings, see Tesla. Tesla (Russian designation: T; international designation: T) is a unit of measurement of magnetic field induction in the International System of Units (SI), numerically equal to the induction of such ... ... Wikipedia

Sievert (symbol: Sv, Sv) is a unit of measurement of effective and equivalent doses of ionizing radiation in the International System of Units (SI), used since 1979. 1 sievert is the amount of energy absorbed by a kilogram ... ... Wikipedia

This term has other meanings, see Becquerel. Becquerel (symbol: Bq, Bq) is a unit of measurement of the activity of a radioactive source in the International System of Units (SI). One becquerel is defined as the activity of a source, in ... ... Wikipedia

This term has other meanings, see Siemens. Siemens (Russian designation: Cm; international designation: S) is a unit for measuring electrical conductivity in the International System of Units (SI), the reciprocal of ohm. Through others ... ... Wikipedia

This term has other meanings, see Pascal (disambiguation). Pascal (symbol: Pa, international: Pa) is a unit of measure for pressure (mechanical stress) in the International System of Units (SI). Pascal is equal to pressure ... ... Wikipedia

This term has other meanings, see Gray. Gray (symbol: Gy, Gy) is a unit of measurement of the absorbed dose of ionizing radiation in the International System of Units (SI). The absorbed dose is equal to one gray, if as a result ... ... Wikipedia

This term has other meanings, see Weber. Weber (symbol: Wb, Wb) is a SI unit of magnetic flux measurement. By definition, a change in magnetic flux through a closed loop at a speed of one weber per second leads to ... ... Wikipedia

This term has other meanings, see Henry. Henry (Russian: H; international: H) is the SI unit for measuring inductance. The circuit has an inductance of one henry, if the current change with speed ... ... Wikipedia

Symbols are commonly used in mathematics to simplify and shorten text. Below is a list of the most common mathematical notations, the corresponding commands in TeX, explanations and examples of use. In addition to these ... ... Wikipedia

A list of specific symbols used in mathematics can be seen in the article Table of mathematical symbols Mathematical notation ("language of mathematics") is a complex graphic notation system used to express abstract ... ... Wikipedia

A list of sign systems (notation systems, etc.) used by human civilization, with the exception of scripts, for which there is a separate list. Contents 1 Listing Criteria 2 Mathematics ... Wikipedia

Paul Adrien Maurice Dirac Paul Adrien Maurice Dirac Date of birth: 8 &… Wikipedia

Dirac, Paul Adrien Maurice Paul Adrien Maurice Dirac Paul Adrien Maurice Dirac Date of birth: 8 August 1902 (... Wikipedia

Gottfried Wilhelm Leibniz ... Wikipedia

This term has other meanings, see Meson (disambiguation). Meson (from other Greek μέσος middle) is a boson of strong interaction. In the Standard Model, mesons are composite (non-elementary) particles composed of an even ... ... Wikipedia

Nuclear physics ... Wikipedia

It is customary to call alternative theories of gravitation theories of gravity that exist as alternatives to the general theory of relativity (GR) or substantially (quantitatively or fundamentally) modify it. To alternative theories of gravity ... ... Wikipedia

It is customary to call alternative theories of gravitation theories of gravity that exist as alternatives to the general theory of relativity or substantially (quantitatively or fundamentally) modify it. To alternative theories of gravity is often ... ... Wikipedia