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 Acceleration one kilogram of mass at the rate of one metre per second squared in the direction of the applied force.
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.
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.
Newton's second law of motion states that , where is the force applied, is the mass of the object receiving the force, and is the acceleration of the object. The newton is therefore:
where the following symbols are used for the units: N for newton, kg for kilogram, m for metre, and s for second.
In dimensional analysis:
where is force, is mass, is length and is time.
At average gravity on Earth (conventionally, ), 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.
- 1 N 0.10197 kg × 9.80665 m/s2 ()
The weight of an average adult exerts a force of about 608 N.
- 608 N 62 kg × 9.80665 m/s2 (where 62 kg is the world average adult mass)
Commonly seen as kilonewtons
It is common to see forces expressed in kilonewtons (kN) where . For example, the tractive effort of a Class Y steam train locomotive and the thrust of an F100 fighter jet engine are both around 130 kN.
One kilonewton, 1 kN, is , or about 100 kg of load.
So for example, a platform that shows it is rated at , will safely support a load.
- 1 kN102 kg × 9.81 m/s2
Specifications in kilonewtons are common in safety specifications for:
the holding values of fasteners, , and other items used in the Construction industry.
working loads in tension and in Shear stress.
rock climbing equipment.
thrust of and
clamping forces of the various moulds in injection moulding machines used to manufacture plastic parts.
Notes and references