Newton

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Categories: Units of force | Articles needing additional references from December 2007

For other uses, see Newton (disambiguation).

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

1 Definition
2 Examples
3 References
4 See also

Definition

The newton is the unit of force in the SI system; it is equal to the amount of force required to give a mass of one kilogram a velocity of one metre per second. Algebraically:

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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 9.81 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 increasingy used when specifying load bearing capacity of items such as ropes and anti-vibration mounts, being approximately equivalent to the more familiar non-SI unit of force, the kgf (or even less correctly, the kg).
The force of Earth's gravity on a human being with a mass of 70 kg is approximately 687 N.
The scalar product of force and distance (N·m)— a force of 1 N exerted over a distance of 1 m— is one joule, the SI unit of energy.
Because a newton is a small force, it is common to see forces expressed in kilonewtons or kN, where 1 kN = 1 000 N.
A metric tonne (1 000 kg) exerts a force of 9.8 kN (or 1 000 kgf) under standard gravity conditions on Earth.