Kilonewton

Kilonewton

For other uses, see Newton (disambiguation).

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The newton (symbol: N) is the SI derived unit of force, named after Isaac Newton in recognition of his work on classical mechanics.

1 Definition
2 Examples
3 Notes
4 References
5 See also

Definition

The newton is the unit of force derived in the SI system; it is equal to the amount of force required to give a mass of one kilogram an acceleration of one meter per second squared. Algebraically:

1N = 1^kg.m⁄_s²

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

Examples

1 N is the force of Earth's gravity on an object with a mass of about 102 g (¹⁄_9.8 kg) (such as a small apple).
On Earth's surface, a mass of 1 kg exerts a force of approximately 9.80665 N [down] (or 1 kgf). The approximation of 1 kg corresponding to 10 N is sometimes used as a rule of thumb in everyday life and in engineering.
The decanewton (daN) = 10 N is increasingly used when specifying load bearing capacity of items such as ropes and anti-vibration mounts because it is approximately equivalent to the more familiar non-SI unit of force, the kgf.
The force of Earth's gravity on a human being with a mass of 70 kg is approximately 687 N.
The dot product of force and distance is mechanical work. Thus, in SI units, a force of 1 N exerted over a distance of 1 m is 1 N·m of work. The Work-Energy Theorem states that the work done on a body is equal to the change in energy of the body. 1 N·m = 1 J (joule), the SI unit of energy.
It is common to see forces expressed in kilonewtons or kN, where 1 kN = 1 000 N.
A tonne (metric ton)=(1 000 kg) exerts a force of 9.80665 kN (or 1 000 kgf) under standard gravity conditions on Earth.

Notes

**Units of force**
	newton (SI unit)	dyne	kilogram-force, 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	≈ 4.448222 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 lb_f	≡ 1 lb·ft/s²
The value of g_n as used in the official definition of the kilogram-force is used here for all gravitational units.

Three approaches to mass and force units
System	Gravitational		Engineering		Absolute
Force (F)	F = m·a		F = m·a/g_c = w·a/g		F = m·a
Weight (w)	w = m·g		w = m·g/g_c ≈ m		w = m·g

Units	English	Metric	English	Metric	English	Metric
Acceleration (a)	ft/s²	m/s²	ft/s²	m/s²	ft/s²	m/s²
Mass (m)	slug	hyl	pound-mass	kilogram	pound	kilogram
Force (F)	pound	kilopond	pound-force	kilopond	poundal	newton

1 kp = 9.80665 N. kp is kilopond 1 kilopond was the measure of 1 kilogram on Earth.

in 1960 this measure was changed to newtons

1 kg on the surface of the Earth weighs 9.8 N, because 1 kg × 9.8 m/s^2 = 9.8 N.

References

^ Serway and Jewett (2008). Physics for Scientists and Engineers

Halliday, Resnick and Walker Fundamentals of Physics, John Wiley & Sons ISBN 0471470619

http://www.sengpielaudio.com/calculator-forceunits.htm

Contents

Definition

Examples

Notes

References

See also