Newton (unit)
Physical unit | |
---|---|
Unit name | Newton |
Unit symbol | |
Physical quantity (s) | force |
Formula symbol | |
dimension | |
system | International system of units |
In SI units | |
In CGS units | |
Named after | Isaac Newton |
Derived from | Kilogram , meter , second |
The Newton [ ˈnjuːtn ] (unit symbol N) is the unit of measurement used in the international system of units (SI) for the physical quantity force . It is a derived unit that can be expressed by the basic units kilogram (kg) , meter (m) and second (s) :
history
The name "Newton" was proposed in 1913 at the 5th General Conference on Weights and Measures (CGPM) as the unit of measurement in the MBS system for force. At the 9th CGPM in 1948, the Newton was officially included in the catalog of named units at the suggestion of the International Union for Physics .
Illustrations
- Dynamic examples (speed changes)
A newton is the magnitude of the force that has to be applied to accelerate a stationary body with a mass of 1 kg uniformly to speed within one second .
Or:
A newton is the magnitude of the force that has to be applied to accelerate a body with a mass of 1 kg .
Or:
A newton is the magnitude of the force that has to be applied to change the speed of a body with a mass of 1 kg every second by moving in a straight line .
- Static examples
If you want to specify the weight of an object in a gravitational field (which is usually done in Newtons), this has to be distinguished from the mass of the object, which is given in kilograms. As a rule of thumb : 1 kg corresponds to about 10 N on the earth's surface , but these quantities, like their units kg and N, are fundamentally different. Since the mean acceleration due to gravity (the so-called local factor) is at sea level , a body with a mass of 1 kg experiences a weight of 9.81 N. Conversely, 1 Newton is the weight that acts on a body with a mass of 102 grams .
Maximum loads on floors are often given in Newtons or Newtons per square meter . The tensile strength of ropes (e.g. tow ropes) or the load limit of cranes are also often given in Newtons - or they have been converted into a permissible mass using the rule of thumb above: You divide the measure belonging to the Newton unit of force by 10, which is the unit of mass To get the measure corresponding to the kilogram:
Common multiples
The unit symbol can be combined with the usual prefixes for units of measure . Common are:
- MN, Meganewtons (1,000,000 Newtons) is a unit used in the thrust of large solid rocket rockets (such as the space shuttle ).
- kN, kilonewton (1,000 Newton) is the usual unit for forces in construction (1 kN corresponds roughly to the weight force that acts on a mass of 100 kg), as well as the thrust of jet and rocket engines for aircraft and large rockets as well as traction and braking power for locomotives and railroad traction vehicles.
- daN, Dekanewton (10 Newtons) is a unit that z. B. is used in lifting technology as well as in load securing to specify the load capacity or the breaking strength of ropes or belts and corresponds approximately to the weight force acting on a mass of 1 kg. A rope with a breaking load of 1000 daN can therefore carry around 1000 kg.
- cN, Centinewton or Centinewton (0.01 Newton) is a common unit used to describe the strength of fibers and yarns (e.g. cN / dtex ) and corresponds roughly to the weight on earth that acts on a mass of 1 gram .
- mN, Millinewton (0.001 Newton) is the common unit of thrust for ion thrusters .
See also
- Newton meter
- Order of magnitude (force) - compilation of everyday and non-everyday forces
Individual evidence
- ^ Minutes of the 5th General Conference on Weights and Measures , 1913, p. 56 (accessed November 11, 2019), French
- ^ Minutes of the 9th General Conference on Weights and Measures , 1948, page 60 (accessed May 26, 2020), French
- ^ Resolution 7 of the 9th meeting of the CGPM (1948) ( online , accessed November 11, 2019), English