Metric System Without Tears
OR
The 9th BIPM Brochure without the confusing, misguided, and contradictory stuff

If you don't know what the Metric System (SI) is

If you are not aware of the 2019 changes

If you are familiar with the 9th BIPM Brochure


Quantity Unit Definition Normalized
Name Symbol
Time second s 9'192'631'770 periods of the radiation emitted by the ground-state hyperfine transition of the caesium 133 atom. 1 s
minute min 60 seconds. 60 s
hour h 60 minutes. 3600 s
day (SI,ATI) d
day
24 hours. 86'400 s
day (UTC) d
day
24 hours, sometimes plus or minus 1 "leap" second. 86'400(±01) s
Length
Distance
Position along a line
Displacement
meter m 1/299'792'458 of the distance traveled by light in one second. 1 m
angstrom 100 picometers. 10−10 m
astronomical unit au 149'597'870'700 meters. 149'597'870'700 m
inch ′′
in
25.4 millimeters. 2.54 × 10−2 m
foot
ft
12 inches. 0.3048 m
yard yd three feet. 0.9144 m
mile mi 1.609 344 kilometers. 1609.344 m
Area square meter m2 Area of a square with sides of 1 meter. 1 m2
hectare ha Area of a square with sides of 100 meters. 10'000 m2
acre ac 43'560 square feet. 4046.856'422'40 m2
barn b 100 square femtometers. 10−28 m2
Volume
Capacity
cubic meter m3 Volume of a cube with sides of 1 meter. 1 m3
liter L
dm3
1/1000 of a cubic meter. 10−3 m3
Velocity, speed meter per second m/s Speed of something that travels 1 meter in 1 second. m s−1
speed of light c Speed of light in vacuum. 299'792'458 m s−1
Acceleration meter per second squared m/s2 Acceleration of something whose speed increases by 1 meter per second in 1 second. m s−2
gal Gal 0.01 meters per second squared. 0.01 m s−2
standard gravity g0 9.80665 meters per second squared. 9.80665 m s−2
Energy in any form joule J 1/6'626'070'15 × 1042 times the energy of a photon of radiation with period 1 second. 1 kg m2 s−2
electronvolt eV 1.602'176'634 × 10−19 joules. 1.602'176'634 × 10−19 kg m2 s−2
large calorie
grand calorie
food calorie
kcal
Cal
4184 joules. 4184 kg m2 s−2
small calorie
gram calorie
cal 4.184 joules. 4.184 kg m2 s−2
Force newton N Force that produces 1 joule of work when applied over a displacement of 1 meter. 1 kg m s−2
dyne dyn Force that accelerates one gram of mass by 1 centimeter per second squared. 0.00001 kg m s−2
pound-force
pound of force
lbf One pound of mass times the standard gravity. 4.4482216152605 kg m s−2
Power watt W Power equivalent to transfer or conversion of one joule of energy per second. 1 kg m2 s−3
Mass gram g Mass that accelerates at 1000 meters per second squared when subjected to 1 newton of force. 10−3 kg
dalton Da 1/12 of the mass of one atom of carbon-12 in the ground state. 1.660'539'040(±20) × 10−27 kg
tonne
metric ton
t 1000 kilograms, or 1 megagram. 103 kg
pound (of mass) lb 0.45359237 kilograms. 0.45359237 kg
Density of a substance or material
Mass concentration in a solution or mixture
Solubility
gram per cubic meter g/m3 Density of a material that has 1 gram of mass in each cubic meter. 10−3 kg m−3
gram per liter
kilogram per cubic meter
g/L
kg/m3
Density of a material that has 1 kilogram of mass in each cubic meter. 1kg m−3
gram per cubic centimeter
tonne per cubic meter
g/cm3
t/m3
Density of a material that has 1 gram of mass in each cubic centimeter. 103 kg m−3
Plane angle
Phase of a sinusoidal function
Amount of rotation
Latitude
Longitude
Azimuth
Elevation
radian rad Central angle spanned on a circle by an arc whose length is equal the radius. 1 rad
turn turn Angle covered by a complete turn. 2 π rad
degree (of angle) °
deg
1/360 of a turn. π/180 rad
minute (of angle)
min
1/60 of a degree of angle. π/10'800 rad
second (of angle) ′′
sec
1/60 of a minute of angle. π/648'000 rad
Angular speed
Phase rate of a sinusoidal function
radian per second rad/s Angular speed of something that rotates through one radian in one second. 1 rad/s
turn per second turn/s Angular speed of something that makes one full turn in one second. 2 π rad/s
degree per second °/s
deg/s
Angular speed of something that rotates through one degree in one second. π/180 rad/s
rotations per minute rpm Angular speed of something that makes one full turn in one minute. π/30 rad/s
Solid angle steradian sr Central solid angle spanned on a sphere by a region with the same area as a square whose side is the radius. 1 sr
Count of cycles of a periodic process cycle cyc One full cycle of the process. 1 cyc
Frequency of a periodic process hertz Hz Frequency of a periodic process that completes one full cycle in one second. 1 cyc s−1
Wavelength of a periodic space function
Image resolution
meter per cycle m/cyc Wavelength of a periodic wave that repeats after 1 meter in the direction normal to the wave . 1 cyc−1 m
Periodicity of a periodic process second per cycle s/cyc Periodicity of a periodic process that completes one full cycle in one second. 1 cyc−1 s
Count of discrete particles (atoms, molecules, ions, nucleons, etc.) particle ptc One particle. 1/6.022'140'76 × 10−23 mol
mole mol 6.022'140'76 × 1023 particles 1 mol
Particle count per volume in a medium
Molarity of a solution
particle per cubic meter ptc/m3 Molarity of a solution or medium that has one particle of the relevant substance in each cubic meter, on average. 1/6.022'140'76 × 10−23 mol m−3
mole per liter
molar
mol/L
M
Molarity of a solution that has 1 mole of the relevant substance in each liter, on average. 103 mol m−3
Rate of particle flow
Reaction rate
Radioactivity
becquerel Bq Radioactivity of a sample that incurs in one nuclear decay event in each second on average. 1/6.022'140'76 × 10−23 mol s−1
particle per second ptc/s Rate of flow, reaction, or decay that amounts to one particle (atom, molecule, photon, etc.) in each second, on average. 1/6.022'140'76 × 10−23 mol s−1
katal kat Rate of chemical reaction that amounts to one mole of the reaction equation per each second. 1 mol s−1
Electric charge elementary charge e Electric charge of one electron or one proton. 1.602'176'634 × 10−19 s A
coulomb C 1/1.602'176'634 × 1019 times the elementary charge. 1 s A
Electric current ampere A Electric current equivalent to a net flow of 1 coulomb of electric charge in one second. 1 A
Electric potential difference
Voltage
volt V Electric potential difference that, when incurred by one coulomb of charge, changes its potential energy by one joule. 1 kg m2 s−3 A−1

Last edited on 2024-07-09 11:50:21 by stolfi