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| | Steradian || Sr || 1sr | | | Steradian || Sr || 1sr |
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| + | | Degree || ⁰ || 1⁰ |
| + | |- |
| + | | Arcminute || arc || 1arc |
| + | |- |
| + | | Grade || grad || 0°54 |
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Revision as of 20:17, 3 February 2024
Prefixes
Like all metric systems, the SI uses metric prefixes to systematically construct, for the same physical quantity, a set of units that are decimal multiples of each other over a wide range.
Prefixes are added to unit names to produce multiples and submultiples of the original unit. All of these are integer powers of ten, and above a hundred or below a hundredth all are integer powers of a thousand.
For example, kilo- denotes a multiple of a thousand and milli- denotes a multiple of a thousandth, so there are one thousand millimetres to the metre and one thousand metres to the kilometre.
The prefixes are never combined, so for example a millionth of a metre is a micrometre, not a millimillimetre. Multiples of the kilogram are named as if the gram were the base unit, so a millionth of a kilogram is a milligram, not a microkilogram.
Units
Acceleration
Name |
Abbreviation |
SI Units
|
Meters Per Second Per Second |
m/s2 |
1 m/s2
|
Gal |
gal |
0.01 m/s2
|
Standard Gravity |
g0 |
0.101972 m/s2
|
Amount of Substance
Name |
Abbreviation |
SI Units
|
Mole |
mol |
1mol
|
Katal |
kat |
1kat
|
Angle
Name |
Abbreviation |
SI Units
|
Radian |
rad |
1rad
|
Steradian |
Sr |
1sr
|
Degree |
⁰ |
1⁰
|
Arcminute |
arc |
1arc
|
Grade |
grad |
0°54
|
Area
Name |
Abbreviation |
SI Units
|
Square Meter |
m2 |
1m2
|
Square Kilometer |
km2 |
1000000m2
|
Square Mile |
mi2 |
≈2590000m2
|
Atomic
Name |
Abbreviation |
SI Units
|
becquerel |
Bq |
1Bq
|
Gray |
Gy |
1Gy
|
sievert |
Sv |
1Sv
|
Current
Name |
Abbreviation |
SI Units
|
Ampere |
A |
1A
|
Force
Name |
Abbreviation |
SI Units
|
Newton |
N |
1N
|
Frequency
Name |
Abbreviation |
SI Units
|
Hertz |
Hz |
1Hz
|
Length
Name |
Abbreviation |
SI Units
|
Millimeter |
mm |
0.001m
|
Centimeter |
cm |
0.01m
|
Decimeter |
dm |
0.1m
|
Meter |
m |
1m
|
Dekameter |
dam |
10m
|
Hectometer |
hm |
100m
|
Kilometer |
km |
1000m
|
Astronomical Unit |
au |
≈149597870691m
|
Luminosity
Name |
Abbreviation |
SI Units
|
Candela |
cd |
1cd
|
Lumens |
lm |
-
|
Lux |
lx |
-
|
Mass
Name |
Abbreviation |
SI Units
|
Picogram |
pg |
0.000000000000001kg
|
Nanogram |
ng |
0.000000000001kg
|
Microgram |
µg |
0.000000001kg
|
Milligram |
mg |
0.000001kg
|
Gram |
g |
0.001kg
|
Kilogram |
kg |
1kg
|
Tonne |
ton |
1000kg
|
Megagram |
Mg |
1000000kg
|
Power
Name |
Abbreviation |
SI Units
|
Watt |
W |
1W
|
Horsepower |
hp |
745.7W
|
Kilowatt |
kW |
1000W
|
Pressure
Name |
Abbreviation |
SI Units
|
Pascal |
Pa |
1Pa
|
Atmosphere |
atm |
101325Pa
|
Temperature
Name |
Abbreviation |
SI Units
|
Degrees Kelvin |
K |
1K
|
Degrees Celsius |
°C |
≈1K+273.15
|
Time
Name |
Abbreviation |
SI Units
|
Planck Time |
tP |
≈0.000000000000000000000000000000000000000000053905s
|
Nanosecond |
ns |
0.000000001s
|
Millisecond |
ms |
0.001s
|
Second |
s |
1s
|
Minute |
min |
60s
|
Hour |
hr |
3600s
|
Day |
day |
86400s
|
Velocity
Name |
Abbreviation |
SI Units
|
Kilometers Per Hour |
km/h |
≈0.278 m/s
|
Meters Per Second |
m/s |
1 m/s
|
Volume
Name |
Abbreviation |
SI Units
|
Cubed Centimeter |
cm3 |
0.000001m3
|
Cubed Meter |
m3 |
1m3
|
Work
Name |
Abbreviation |
SI Units
|
Joule |
J |
1J
|
Calorie |
cal |
4.184J
|
Kilocalorie |
kcal |
4184J
|
Kilowatt-Hour |
kWh |
3600000J
|