The Physics
Factbook
An encyclopedia of scientific essays

About Units

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Acceptable Units

The following units are acceptable for use in the "standardized result" column of your final submission.

Quantity,
Synonyms or Related Quantities
SI Unit,
Symbol
Other Units,
Symbol w/Notes
Acceleration
 
m/s2 g
(multiples of 9.8 m/s2)
Angular Velocity
(Angular Speed, Rate of Rotation)
rad/s rpm
Area
 
m2 -
Density
 
kg/m3 molecule/m3
Electric Current
(Amperage)
amp, A
(a.k.a. ampère)
-
Electric Field
 
V/m or N/C
(identical units)
-
Electric Potential
(Electromotive Force, Potential Difference, Voltage)
volt, V -
Electrical Resisitivity
(Reciprocal of Electrical Conductivity)
Ω·m -
Energy
(Energy Density)
joule, J electron volt, eV
J/kg (energy density)
Force
(Lift, Tension, Weight, etc.)
newton, N -
Friction
(Coefficient of Friction)
- -
Frequency
 
hertz, Hz -
Length
(Altitude, Diameter, Distance, Size, Thickness, Wavelength)
meter, m light-year
Magnetic Field
(Magnetic Flux Density, Magnetic Induction)
tesla, T Wb/m2 or N/Am
(identical to tesla)
Mass
 
kilogram, kg solar masses
atomic mass unit, amu
Money
(Cost, Earnings, Income, Price, Salary, Worth)
$US $US/g, $US/kg, $US/L, $US/m3, $US/J, etc.
Number
 
- -
Power
(Power Density)
watt, W W/m2
(power density)
Pressure
 
pascal, Pa atmosphere, atm
Refraction
(Index of Refraction, Refractive Index)
- -
Temperature
 
kelvin, K degree celsius, °C
Time
(Age, Half-life, Period)
second, s year, yr
Velocity
(Speed)
m/s -
Volume
 
m3 liter, L

Acceptable Prefixes

The following prefixes may be used in conjunction with the acceptable units given above. The use of prefixes is preferred to the use of scientific notation in most cases.

Multiples Divisions
SI Prefix Symbol Value SI Prefix Symbol Value
kilo k 103 milli m 10−3
mega M 106 micro µ 10−6
giga G 109 nano n 10−9
tera T 1012 pico p 10−12
peta P 1015 femto f 10−15
exa E 1018 atto a 10−18

Conversion Resources

Learn to use Google Calculator. Not only does it do conversions, but it can also do computations with mixed units and state the answer with the correct SI unit.