Newton (unit)
Template:Use British English Oxford spelling Template:Infobox unit
The newton (symbol: N) is the unit of force in the International System of Units (SI). Expressed in terms of SI base units, it is 1 kg⋅m/s2, the force that accelerates a mass of one kilogram at one metre per second squared.
The unit is named after Isaac Newton in recognition of his work on classical mechanics, specifically his second law of motion.
Definition
[edit]A newton is defined as 1 kg⋅m/s2 (it is a named derived unit defined in terms of the SI base units).[1]: 137 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.[2]
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 one metre per second every second.[2]
In 1946, the General Conference on Weights and Measures (CGPM) Resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate one kilogram of mass at the rate of one metre per second squared. In 1948, the 9th CGPM Resolution 7 adopted the name newton for this force.[3] The MKS system then became the blueprint for today's SI system of units.[4] The newton thus became the standard unit of force in the Système international d'unités (SI), or International System of Units.[3]
The connection to Newton comes from Newton's second law of motion, which states that the force exerted on an object is directly proportional to the acceleration hence acquired by that object, thus:[5] where represents the mass of the object undergoing an acceleration . When using the SI unit of mass, the kilogram (kg), and SI units for distance metre (m), and time, second (s) we arrive at the SI definition of the newton: 1 kg⋅m/s2.
Examples
[edit]At average gravity on Earth (conventionally, = 9.80665 m/s2), a kilogram mass exerts a force of about 9.81 N.
- An average-sized apple with mass 200 g exerts about two newtons of force at Earth's surface, which we measure as the apple's weight on Earth.
- An average adult exerts a force of about 608 N on Earth.
- Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 62\text { kg} \times 9.80665 \text{ m/s}^2=608\text{ N} } (where 62 kg is the world average adult mass).[6]
Kilonewtons
[edit]
Large forces may be 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.[citation needed]
Climbing ropes are tested by assuming a human can withstand a fall that creates 12 kN of force. The ropes must not break when tested against 5 such falls.[7]: 11
Conversion factors
[edit]Template:Units of force Template:GravEngAbs Template:SI multiples
See also
[edit]- Force gauge
- International System of Units – Modern form of the metric system
- joule – SI unit of energy
- kilogram-force
- kip (unit)
- newton-metre
- Orders of magnitude (force)
- Pascal (unit) – SI derived unit of pressure
- pound (force)
- sthène
References
[edit]- ↑ Bureau International des Poids et Mesures (2019). The International System of Units (SI) (PDF) (9 ed.). Bureau International des Poids et Mesures (BIPM). p. 137. Archived from the original on 30 September 2021. Retrieved 22 September 2021.
- ↑ 2.0 2.1 "Newton | unit of measurement". Encyclopædia Britannica. 17 December 2020. Archived from the original on 27 September 2019. Retrieved 27 September 2019.
- ↑ 3.0 3.1 The International System of Units (SI) (1977 ed.). U.S. Department of Commerce, National Bureau of Standards. 1977. p. 17. ISBN 9282220451. Archived from the original on 11 May 2016. Retrieved 15 November 2015.
- ↑ David B. Newell; Eite Tiesinga, eds. (2019). The International System of Units (SI) (PDF) (NIST Special publication 330, 2019 ed.). Gaithersburg, MD: NIST. Retrieved 30 November 2019.
- ↑ "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 18 June 2007.
- ↑ Walpole, Sarah Catherine; Prieto-Merino, David; et al. (18 June 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.
- ↑ Bright, Casandra Marie. "A History of Rock Climbing Gear Technology and Standards." (2014).