Newton

This article is about the SI unit of force. For other uses see Newton (disambiguation)

In physics, the newton (symbol: N) is the SI unit of force, named after Sir Isaac Newton in recognition of his work on classical mechanics. It was first used around 1904, but not until 1948 was it officially adopted by the General Conference on Weights and Measures (CGPM) as the name for the mks unit of force.

A newton is defined as the amount of force required to accelerate a mass of one kilogram at a rate of one metre per second squared.

The newton is an SI derived unit, comprising kg × m × s^-2 in SI base units.

Since one definition of weight is the force acting between two objects due to gravity, the newton is also the unit of weight. A mass of one kilogram near the Earth's surface has a weight of approximately 9.81 newtons, although this figure varies by a few tenths of one per cent over the Earth's surface. Conversely, an object with a mass of 9.81^-1 kg (≈101.94 grams) weighs roughly one newton. Rather fittingly, given the story about how Newton arrived at his theory of gravity, this is about the mass of a small apple.

Units of force
	Newton	Dyne	Kilopond	Pound-force	Poundal
1 N	:= 1 kg·m/s²	= 10⁵ dyn	~= 0.10197 kp	~= 0.22481 lb_f	~= 7.2330 pdl
1 dyn	= 10⁻⁵ N	:= 1 g·cm/s²	~= 1.0197×10⁻⁶ kp	~= 2.2481×10⁻⁶ lb_f	~= 7.2330×10⁻⁵ pdl
1 kp	= 9.80665 N	= 980665 dyn	:= g_n·(1 kg)	~= 2.2046 lb_f	~= 70.932 pdl
1 lb_f	= 4.4482216152605 N	~= 444822 dyn	~= 0.45359 kp	:= g_n·(1 lb)	~= 32.174 pdl
1 pdl	= 0.138254954376 N	~= 13825 dyn	~= 0.014098 kp	~= 0.031081 lb_f	:= 1 lb·ft/s²
The values for the pound-force are calculated using the same value for the standard acceleration of gravity g_n which is official for defining the kilopond (a.k.a. kilogram-force), something which is not required. Other values such as g_n = 32.16 ft/s² are also used.

Newton

See also