نيوتن (وحدة)

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newton
Visualization of one newton of force
معلومات عامة
نظام الوحدات	SI
وحدة قياس	force
الرمز	N
مسمى على اسم	Sir Isaac Newton
التحويلات
1 N في ...	... يساوي ...
SI base units	1 kg⋅m⋅s−2
CGS units	105 dyn
Imperial units	0.224809 lbf

نيوتن Newton هي وحدة القوة في نظام المتر كيلوگرام ثانية، وهي القوة التي لو أثرت على كتلة كيلوگرام واحد لأكسبتها تعجيل مقداره متر في الثانية في الثانية.

سميت هذه الوحدة بالنيوتن تخليدا للعالم سير إسحق نيوتن العالم الفيزيائي والرياضي الإنكليزي.

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 التعريف

A newton is defined as $1\ {\text{kg}}\cdot {\text{m/s}}^{2}$ (it is a derived unit which is defined in terms of the SI base units). One newton is, therefore, the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in the direction of the applied force.

The units "metre per second squared" can be understood as measuring a rate of change in velocity per unit of time, i.e. an increase in velocity by 1 metre per second every second.

In 1946, the Conférence Générale des Poids et Mesures (CGPM) Resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate 1 kilogram of mass at the rate of 1 metre per second squared. In 1948, the 9th CGPM Resolution 7 adopted the name newton for this force. The MKS system then became the blueprint for today's SI system of units. The newton thus became the standard unit of force in the Système international d'unités (SI), or International System of Units.

This SI unit is named after Isaac Newton. As with every International System of Units (SI) unit named for a person, the first letter of its symbol is upper case (N). However, when an SI unit is spelled out in English, it should always begin with a lower case letter (newton)—except in a situation where any word in that position would be capitalized, such as at the beginning of a sentence or in material using title case. Note that "degree Celsius" conforms to this rule because the "d" is lowercase.— Based on The International System of Units, section 5.2.

In more formal terms, Newton's second law of motion states that the force exerted on an object is directly proportional to the acceleration hence acquired by that object, thus:

$F=ma,$

where m represents the mass of the object undergoing an acceleration a. As a result, the newton may be defined in terms of the kilogram (${\text{kg}}$), metre (${\text{m}}$), and second (${\text{s}}$) as

$1\ {\text{N}}=1\ {\frac {{\text{kg}}{\cdot }{\text{m}}}{{\text{s}}^{2}}}.$

 أمثلة

At average gravity on Earth (conventionally, $g={9.80665}\ {\text{m/s}}^{2}$), a kilogram mass exerts a force of about 9.8 newtons.

• An average-sized apple at 200 g exerts about two newtons of force at Earth's surface, which we measure as the apple's weight on Earth.

$0.200{\text{ kg}}\times 9.80665{\text{ m/s}}^{2}=1.961{\text{ N}}.$

• An average adult exerts a force of about 608 N on Earth.

$62{\text{ kg}}\times 9.80665{\text{ m/s}}^{2}=608{\text{ N}}$ (where 62 kg is the world average adult mass).

 كيلونيوتن

A carabiner used in rock climbing, with a safety rating of 26 kN when loaded along the spine with the gate closed, 8 kN when loaded perpendicular to the spine, and 10 kN when loaded along the spine with the gate open.

It is common to see forces expressed in kilonewtons (kN), where 1 kN = 1000 N. For example, the tractive effort of a Class Y steam train locomotive and the thrust of an F100 jet engine are both around 130 kN.

One kilonewton, 1 kN, is equivalent to 102.0 kgf, or about 100 kg of load under Earth gravity.

$1{\text{ kN}}=102{\text{ kg}}\times 9.81{\text{ m/s}}^{2}$.

So, for example, a platform that shows it is rated at 321 kilonewtons (72,000 lb_f) will safely support a 32,100-kilogram (70,800 lb) load.

Specifications in kilonewtons are common in safety specifications for:

• the holding values of fasteners, Earth anchors, and other items used in the building industry;
• working loads in tension and in shear;
• rock-climbing equipment;
• thrust of rocket engines, Jet engines and launch vehicles;
• clamping forces of the various moulds in injection-moulding machines used to manufacture plastic parts.

 عوامل التحويل

سوابق النظام الدولي للوحدات

مضاعفات	اسم السابقة		ديسا	هكتو	كيلو	ميگا	گيگا	تيرا	پيتا	إكسا	زيتا	يوتا
	رمز السابقة		da	h	k	M	G	T	P	E	Z	Y
	العامل	100	101	102	103	106	109	1012	1015	1018	1021	1024
المضاعفات الفرعية	اسم السابقة		ديسي	سنتي	ملي	ميكرو	نانو	پيكو	فمتو	اتو	زپتو	يوكتو
	رمز السابقة		d	c	m	μ	n	p	f	a	z	y
	العامل	100	10−1	10−2	10−3	10−6	10−9	10−12	10−15	10−18	10−21	10−24

 انظر أيضاً

• Force gauge
• International System of Units (SI)
• Joule, SI unit of energy, 1 newton exerted over a distance of 1 metre
• Kilogram-force, force exerted by Earth's gravity at sea level on one kilogram of mass
• Kip (unit)
• Pascal, SI unit of pressure, 1 newton acting on an area of 1 square metre
• Orders of magnitude (force)
• Pound (force)
• Sthène
• Newton metre, SI unit of torque

 الهامش

وحدات القوة

	نيوتن (وحدات SI)	داين	كيلوجرام-قوة (Kilopond)	رطل-قوة	باوندال
1 نيوتن	≡ 1 كجم·م/ث²	= 105 داين	≈ 0.10197 كجم-قوة	≈ 0.22481 رطلق	≈ 7.2330 باوندال
1 داين	= 10−5 نيوتن	≡ 1 جم·سم/ث²	≈ 1.0197 كجم-قوة	≈ 2.2481 رطلق	≈ 7.2330 باوندال
1 كجم- قوة	= 9.80665 نيوتن	= 980665 داين	≡ gn·(1 كجم)	≈ 2.2046 رطلق	≈ 70.932 باوندال
1 رطلق	≈ 4.448222 نيوتن	≈ 444822 داين	≈ 0.45359 كجم-قوة	≡ gn·(1 lb)	≈ 32.174 باوندال
1 باوندال	≈ 0.138255 نيوتن	≈ 13825 داين	≈ 0.014098 كجم-قوة	≈ 0.031081 رطلق	≡ 1 رطل·قدم/ث²
قيمة gn المستخدمة هنا لجميع وحدات الجاذبية مساوية لقيمنها في التعريف الرسمي للكيلوجرام-قوة.