Newton - what is it? Newton - a unit of what?

Physics as a science that studies the laws of our universe uses the standard research methodology and a certain system of units of measurement. The unit of force is usually designated H (newton). What is power, how to find it and measure it? Let's study this issue in more detail.

Interesting from history

Isaac Newton is an outstanding English scholar of the 17th century who made an invaluable contribution to the development of exact mathematical sciences. He is the forefather of classical physics. He managed to describe the laws, which obey both the huge celestial bodies, and fine grains, carried away by the wind. One of his main discoveries is the law of universal gravitation and the three basic laws of mechanics that describe the interaction of bodies in nature. Later, other scientists were able to derive the laws of friction, rest and slip only thanks to the scientific discoveries of Isaac Newton.

A bit of theory

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

The magnitude of the force is measured in Newtons for a reason. It was to these scientists that three unshakable "law enforcement" laws were created, which are still valid today. Let's study them on examples.

The First Law

To fully understand the questions: "What is Newton?", "Unit of measurement of what?" And "What is its physical meaning?", It is worth carefully studying the three basic laws of mechanics.

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 motion along a straight line.

Imagine that on a flat surface of the table is a certain book with a certain mass. Denoting all the forces acting on it, we get that it is the force of gravity, which is directed vertically downward, and the reaction force of the support (in this case of the table), directed vertically upwards. Since both forces counterbalance each other's actions, the magnitude of the resultant force is zero. According to Newton's first law, it is for this reason that the book rests.

The 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. Isaak Newton, when formulating this law, first used the constant mass value as a measure of inertia and inertia of the body. Inertness refers to 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 strength 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 does it relate 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 with velocities much less than the speed of light. At velocities close to the speed of light, there are already a few other laws that are adapted by a special section of physics on the theory of relativity.

Newton's third law

This is perhaps the most understandable and simple 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 has an effect on the first with equal strength in modulus.

The very formulation of the law to scientists looks like this: "... the interactions of two bodies on each other are equal to one another, but they are directed in opposite directions."

Let's see what Newton is. In physics, it is customary to consider everything on concrete phenomena, so we give some examples describing the laws of mechanics.

1. Waterfowl like ducks, fish or frogs move in water or on water precisely because of interaction with it. Newton's third law says that when one body acts on another, there is always opposition, which is equivalent in strength to the first, but directed in the opposite direction. Proceeding from this, it can be concluded that the movement of the ducks is due to the fact that they pushes the water back with paws, and they themselves float forward due to the reciprocal action of the water.
2. The squirrel wheel is a vivid example of the proof of Newton's third law. What is a squirrel wheel, for sure everyone knows. This is a fairly simple design, reminiscent of both the wheel and the drum. It is installed in cages so that pets such as squirrels or decorative rats can run. The interaction of two bodies, the wheel and the animal, leads to the fact that both these bodies are moving. And when the protein runs fast, then the wheel spins at a high speed, and when it slows down, the wheel starts to spin more slowly. This once again proves that action and counteraction are always equal, although they are directed in opposite directions.
3. Everything that moves on our planet moves only because of the "response action" of the Earth. This may seem strange, but in fact, when walking, we make efforts only to push the ground or any other surface. And we are moving forward, because the earth pushes us in response.

What is Newton: unit or physical quantity?

The very definition of "Newton" can be described as follows: "This is a unit of force." And what is its physical meaning? So, based on Newton's second law, it is a derivative quantity, which is defined as a force that can change the speed of a body of 1 kg per 1 m / s in just 1 second. It turns out that a newton is a vector quantity, that is, it has its own direction. When we apply force to an object, for example pushing a door, we simultaneously specify 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 often necessary to convert newtons to other quantities. For convenience in finding these or those values it is recommended to remember the basic identities that connect the newtons with other units:

• 1 H = 10 ⁵ dyne (dyne - unit of measurement in the GHS system);
• 1 Н = 0.1 kgf (kilogram-force - unit of force in the ICGSS system);
• 1 Н = 10 ^-3 walls (unit of measurement in the MTS system, 1 wall is equal to the force that reports acceleration in 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 notion of our planet, is the law of gravitation of Newton (what is gravity, read below). Of course, before him there were attempts to unravel the mystery of the attraction of the Earth. For example, Johannes Kepler was the first to suggest that not only the Earth has an attractive force, but also the bodies themselves are able to attract the Earth.

However, only Newton managed to prove mathematically the relationship between gravitational force and the law of motion of 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 body, including the celestial bodies, is attracted with a force equal to the product of G (the gravitational constant) and the masses of both bodies m ₁ * m ₂ , divided by R ² (the square of the distance between the bodies).

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

Conversion of units

When solving problems, remember the standard SI prefixes, which are used, among other things, for "Newtonian" units of measurement. For example, in problems about cosmic objects, where the masses of bodies are large, very often there is a need to simplify large values to smaller ones. If the solution is 5000 N, then the answer is more convenient to write in the form 5 kN (kiloNewton). Such units are of two types: multiple and lobed. Here are the most used of them: 10 ² H = 1 hectareNewton (gN); 10 ³ N = 1 kiloNewton (kN); 10 ⁶ Н = 1 megaNewton (MN) and 10 ^-2 Н = 1 centiNewton (сН); 10 ^-3 H = 1 millionNewton (mN); 10 ^-9 H = 1 nano-Newton (nH).