newton | |
---|---|

Visualization of one newton of force | |

General information | |

Unit system | SI derived unit |

Unit of | Force |

Symbol | N |

Named after | Sir Isaac Newton |

Conversions | |

1 N in ... | ... is equal to ... |

SI base units | 1 kg⋅m⋅s ^{−2} |

British Gravitational System | 0.2248089 lb_{f} |

The **newton** (symbol: **N**) is the International System of Units (SI) derived unit of force. It is named after Isaac Newton in recognition of his work on classical mechanics, specifically Newton's second law of motion.

See below for the conversion factors.

*One newton is 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.*^{ [1] } The units "metre per second squared" can be understood as change in velocity per time, i.e. an increase of velocity by 1 metre per second every second.

In 1946, 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.^{ [2] } 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.

The newton is named after Isaac Newton . As with every SI unit named for a person, its symbol starts with an upper case letter (N), but when written in full it follows the rules for capitalisation of a common noun ; i.e., "*newton*" becomes capitalised at the beginning of a sentence and in titles, but is otherwise in lower case.

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, namely:^{ [3] }

where the proportionality constant represents the mass of the object undergoing an acceleration . As a result, the *newton* may be defined in terms of kilograms (), metres (), and seconds () as

At average gravity on Earth (conventionally, *g* = 9.80665 m/s^{2} ), a kilogram mass exerts a force of about 9.8 newtons. An average-sized apple exerts about one newton of force, which we measure as the apple's weight.^{ [4] }

- 1 N = 0.10197 kg × 9.80665 m/s
^{2}(0.10197 kg = 101.97 g).

The weight of an average adult exerts a force of about 608 N.

- 608 N = 62 kg × 9.80665 m/s
^{2}(where 62 kg is the world average adult mass).^{ [5] }

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 kN = 102 kg × 9.81 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 kilograms (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.

newton (SI unit) | dyne | kilogram-force, kilopond | pound-force | poundal | |
---|---|---|---|---|---|

1 N | ≡ 1 kg⋅m/s^{2} | = 10^{5} dyn | ≈ 0.10197 kp | ≈ 0.22481 lbf | ≈ 7.2330 pdl |

1 dyn | = 10^{–5} N | ≡ 1 g⋅cm/s^{2} | ≈ 1.0197 × 10^{–6} kp | ≈ 2.2481 × 10^{–6} lbf | ≈ 7.2330 × 10^{–5} pdl |

1 kp | = 9.80665 N | = 980665 dyn | ≡ g_{n} ⋅ (1 kg) | ≈ 2.2046 lbf | ≈ 70.932 pdl |

1 lbf | ≈ 4.448222 N | ≈ 444822 dyn | ≈ 0.45359 kp | ≡ g_{n} ⋅ (1 lb) | ≈ 32.174 pdl |

1 pdl | ≈ 0.138255 N | ≈ 13825 dyn | ≈ 0.014098 kp | ≈ 0.031081 lbf | ≡ 1 lb⋅ft/s^{2} |

The value of g_{n} as used in the official definition of the kilogram-force is used here for all gravitational units. |

Base | Force | Weight | Mass | |||||
---|---|---|---|---|---|---|---|---|

2nd law of motion | m = F/a | F = W⋅a/g | F = m⋅a | |||||

System | BG | GM | EE | M | AE | CGS | MTS | SI |

Acceleration (a) | ft/s^{2} | m/s^{2} | ft/s^{2} | m/s^{2} | ft/s^{2} | Gal | m/s^{2} | m/s^{2} |

Mass (m) | slug | hyl | pound-mass | kilogram | pound | gram | tonne | kilogram |

Force (F),weight ( W) | pound | kilopond | pound-force | kilopond | poundal | dyne | sthène | newton |

Pressure (p) | pounds per square inch | technical atmosphere | pounds-force per square inch | atmosphere | poundals per square foot | barye | pieze | pascal |

Prefix name | N/A | deca- | hecto- | kilo- | mega- | giga- | tera- | peta- | exa- | zetta- | yotta- |
---|---|---|---|---|---|---|---|---|---|---|---|

Prefix symbol | da- | h- | k- | M- | G- | T- | P- | E- | Z- | Y- | |

Factor | 10^{0} | 10^{1} | 10^{2} | 10^{3} | 10^{6} | 10^{9} | 10^{12} | 10^{15} | 10^{18} | 10^{21} | 10^{24} |

Prefix name | N/A | deci- | centi- | milli- | micro- | nano- | pico- | femto- | atto- | zepto- | yocto- |
---|---|---|---|---|---|---|---|---|---|---|---|

Prefix symbol | d- | c- | m- | μ- | n- | p- | f- | a- | z- | y- | |

Factor | 10^{0} | 10^{–1} | 10^{–2} | 10^{–3} | 10^{–6} | 10^{–9} | 10^{–12} | 10^{–15} | 10^{–18} | 10^{–21} | 10^{–24} |

- 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

The **kilogram** is the base unit of mass in the International System of Units (SI), the current metric system, having the unit symbol **kg**. It is a widely used measure in science, engineering and commerce worldwide, and is often simply called a **kilo** in everyday speech.

The **litre** or **liter** is a metric unit of volume. It is equal to 1 cubic decimetre (dm^{3}), 1000 cubic centimetres (cm^{3}) or 0.001 cubic metre (m^{3}). A cubic decimetre occupies a volume of 10 cm × 10 cm × 10 cm and is thus equal to one-thousandth of a cubic metre.

**Mass** is both a property of a physical body and a measure of its resistance to acceleration when a net force is applied. An object's mass also determines the strength of its gravitational attraction to other bodies.

The **International System of Units** is the modern form of the metric system. It is the only system of measurement with an official status in nearly every country in the world. It comprises a coherent system of units of measurement starting with seven base units, which are the second, metre, kilogram, ampere, kelvin, mole, and candela. The system allows for an unlimited number of additional units, called derived units, which can always be represented as products of powers of the base units. Twenty-two derived units have been provided with special names and symbols. The seven base units and the 22 derived units with special names and symbols may be used in combination to express other derived units, which are adopted to facilitate measurement of diverse quantities. The SI system also provides twenty prefixes to the unit names and unit symbols that may be used when specifying power-of-ten multiples and sub-multiples of SI units. The SI is intended to be an evolving system; units and prefixes are created and unit definitions are modified through international agreement as the technology of measurement progresses and the precision of measurements improves.

In science and engineering, the **weight** of an object is the force acting on the object due to gravity.

The **pound of force** or **pound-force** is a unit of force used in some systems of measurement including English Engineering units and the foot–pound–second system. Pound-force should not be confused with foot-pound, a unit of energy, or pound-foot, a unit of torque, that may be written as "lbf⋅ft"; nor should these be confused with pound-mass, often simply called *pound*, which is a unit of mass.

The **newton-metre** is a unit of torque in the SI system. One newton-metre is equal to the torque resulting from a force of one newton applied perpendicularly to the end of a moment arm that is one metre long. The nonstandard notation *Nm* occurs in some fields.

The **kilogram-force**, or **kilopond**, is a non-standard gravitational metric unit of force. It is equal to the magnitude of the force exerted on one kilogram of mass in a 9.80665 m/s^{2} gravitational field. That is, it is the weight of a kilogram under standard gravity. Therefore, one kilogram-force is by definition equal to 9.80665 N. Similarly, a gram-force is 9.80665 mN, and a milligram-force is 9.80665 μN.

The **metre per second squared** is the unit of acceleration in the International System of Units (SI). As a derived unit, it is composed from the SI base units of length, the metre, and time, the second. Its symbol is written in several forms as **m/s ^{2}**,

The **newton-second** is the derived SI unit of impulse. It is dimensionally equivalent to the momentum unit **kilogram-metre per second** (**kg⋅m/s**). One newton-second corresponds to a one-newton force applied for one second.

A **kilogram-force per centimetre square** (kgf/cm^{2}), often just **kilogram per square centimetre** (kg/cm^{2}), or **kilopond per centimetre square** is a deprecated unit of pressure using metric units. It is not a part of the International System of Units (SI), the modern metric system. 1 kgf/cm^{2} equals 98.0665 kPa (kilopascals). It is also known as a **technical atmosphere**.

The **standard acceleration due to gravity**, sometimes abbreviated as **standard gravity**, usually denoted by *ɡ*_{0} or *ɡ*_{n}, is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth. It is defined by standard as 9.80665 m/s^{2}. This value was established by the 3rd CGPM and used to define the standard weight of an object as the product of its mass and this nominal acceleration. The acceleration of a body near the surface of the Earth is due to the combined effects of gravity and centrifugal acceleration from the rotation of the Earth ; the total is about 0.5% greater at the poles than at the Equator.

The **gravitational metric system** is a non-standard system of units, which does not comply with the International System of Units (SI). It is built on the three base quantities length, time and force with base units metre, second and kilopond respectively. Internationally used abbreviations of the system are **MKpS**, **MKfS** or **MKS** . However, the abbreviation MKS is also used for the MKS system of units, which, like the SI, uses mass in kilogram as a base unit.

The **foot–pound–second system** or **FPS system** is a system of units built on three fundamental units: the foot for length, the (avoirdupois) pound for either mass or force, and the second for time.

The **gravity of Earth**, denoted by **g**, is the net acceleration that is imparted to objects due to the combined effect of gravitation and the centrifugal force.

**Metric units** are units based on the metre, gram or second and decimal multiples or sub-multiples of these. The most widely used examples are the units of the International System of Units (SI). By extension they include units of electromagnetism from the CGS and SI units systems, and other units for which use of SI prefixes has become the norm. Other unit systems using metric units include:

In common usage, the **mass** of an object is often referred to as its **weight**, though these are in fact different concepts and quantities. In scientific contexts, mass is the amount of "matter" in an object, whereas weight is the force exerted on an object by gravity. In other words, an object with a mass of 1.0 kilogram weighs approximately 9.81 newtons on the surface of the Earth, which is its mass multiplied by the gravitational field strength. The object's weight is less on Mars, where gravity is weaker, and more on Saturn, and very small in space when far from any significant source of gravity, but it always has the same mass.

A **unit of measurement** is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement. For example, a length is a physical quantity. The metre is a unit of length that represents a definite predetermined length. When we say 10 metres, we actually mean 10 times the definite predetermined length called "metre". Measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind.

Effective 20 May 2019, the 144th anniversary of the Metre Convention, the SI base units were redefined in agreement with the International System of Quantities. In the redefinition, four of the seven SI base units – the kilogram, ampere, kelvin, and mole – were redefined by setting exact numerical values for the Planck constant, the elementary electric charge, the Boltzmann constant, and the Avogadro constant, respectively. The second, metre, and candela were already defined by physical constants and were not subject to correction to their definitions. The new definitions aimed to improve the SI without changing the value of any units, ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures (CGPM) unanimously approved these changes, which the International Committee for Weights and Measures (CIPM) had proposed earlier that year after determining that previously agreed conditions for the change had been met. These conditions were satisfied by a series of experiments that measured the constants to high accuracy relative to the old SI definitions, and were the culmination of decades of research.

The history of the metric system began during the Age of Enlightenment with measures of length and weight derived from nature, along with their decimal multiples and fractions. The system became the standard of France and Europe within half a century. Other measures with unity ratios were added, and the system went on to be adopted across the world.

- ↑ "Newton | unit of measurement".
*Encyclopedia Britannica*. Retrieved 2019-09-27. - ↑ International Bureau of Weights and Measures (1977),
*The International System of Units*(3rd ed.), U.S. Dept. of Commerce, National Bureau of Standards, p. 17, ISBN 0745649742. - ↑ "Table 3. Coherent derived units in the SI with special names and symbols".
*The International System of Units (SI)*. International Bureau of Weights and Measures. 2006. Archived from the original on 2007-06-18. - ↑ Whitbread BSc (Hons) MSc DipION, Daisy. "How much is 100 grams?" . Retrieved 22 September 2020.
- ↑ Walpole, Sarah Catherine; Prieto-Merino, David; Edwards, Phillip; Cleland, John; Stevens, Gretchen; Roberts, Ian (2012). "The weight of nations: an estimation of adult human biomass".
*BMC Public Health*.**12**(12): 439. doi:10.1186/1471-2458-12-439. PMC 3408371 . PMID 22709383. - ↑ Comings, E. W. (1940). "English Engineering Units and Their Dimensions".
*Industrial & Engineering Chemistry*.**32**(7): 984–987. doi:10.1021/ie50367a028. - ↑ Klinkenberg, Adrian (1969). "The American Engineering System of Units and Its Dimensional Constant g
_{c}".*Industrial & Engineering Chemistry*.**61**(4): 53–59. doi:10.1021/ie50712a010.

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