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 Posted: Sun Jun 04, 2006 3:48 pm
Upon some suggestions, we thought it best to include this to help you while navigating through the Physics Guild. Here you will find a list of short forms and some general terms for all things which we deemed useful and necessary. If you feel there is something omitted, please tell us in this thread, and if you are unfamiliar with a short form which someone has used but is not found here, please also tell us in this thread so that we may include it. This list will continually be updated. Each list is in alphabetical order.
Last revision: 23 Jun 2006 ~ Vorpal
General Terms
EM - Electromagnetism (or electromagnetic)
EWSB - Electroweak symmetry breaking
GTR / GR - General Theory of Relativity
HUP - Heisenberg's uncertainy principle
PEP - Pauli's exclusion principle
QCD - Quantum chromodynamics
QED - Quantum electrodynamics
QFT - Quantum field theory
QM - Quantum mechanics
RQM - Relativistic quantum mechanics
STR / SR - Special Theory of Relatvity
SI prefixes
Factor==Exponent Form==Prefix (Symbol)
10^24==E24==yotta (Y)
10^21==E21==zetta (Z)
10^18==E18==exa (E)
10^15==E15==peta (P)
10^12==E12==tera (T)
10^9==E9==giga (G)
10^6==E6==mega (M)
10^3==E3==kilo (k)
10^2==E2==hecto (h)
10^1==E1==deca (da)
10^-1==E-1==deci (d)
10^-2==E-2==centi (c)
10^-3==E-3==milli (m)
10^-6==E-6==micro (µ)
10^-9==E-9==nano (n)
10^-12==E-12==pico (p)
10^-15==E-15==femto (f)
10^-18==E-18==atto (a)
10^-21==E-21==zepto (z)
10^-24==E-24==yocto (y)
A comparison of SI units with cgs and U.S. customary units follows. Values marked with ≡ are exact, either directly by definition or by inference from other definitions. The uncertainty is in reference to the last given digits, so that 6.0221415e23 with uncertainty 10 means (6.0221415±0.0000010)e23.
Dimensionless
mole (mol): 1 mol = 6.0221415e23 units (uncertainty 10) [Avogadro's number]
Length
SI unit: meter (m)
angstrom (Å): 1 Å ≡ 100 pm ≡ 1e-10 m
astronomical unit (AU): 1 AU = 1.49597870691e11 m (uncertainty 30)
centimeter (cm): 100 cm ≡ 1m
inch (in): 1 in ≡ 2.54 cm ≡ 0.0254 m
fermi (fm): 1 fm ≡ 1e-15 m [femtometer]
foot (ft): 1 ft ≡ 12 in ≡ 0.3048 m
light-year [ly]: 1 ly = 5.8786e12 mi = 6.3241e4 AU = 9.4607e15 m
mile (mi): 1 mi ≡ 1.609344 km ≡ 1.609344e3 m
[ly] By definition, 1 ly ≡ (31557600s)(299792458m/s), in reference to a Julian year.
Mass
SI unit: kilogram (kg), rather than gram
electron (m_e): 1 m_e = 0.510998918 MeV (U44) = 9.1093826e-31kg (U16)
electron-volt (eV/c²): 1 eV/c² = 1.78266181e-36 kg (uncertainty 15)
gram: 1000 g ≡ 1 kg
pound-mass (lbm): 1 lbm ≡ 0.45359237 kg
Time
SI unit: second (s)
Hertz (Hz): 1 Hz ≡ 1/s
year (tropical): 365.242190 days = 3.15569252e7 s
year (Julian): 365.25 days ≡ 3.1557600e7 s
Temperature
SI Unit: kelvin (K)
Celcius (°C): C ≡ (5/9)(F - 32) = K - 273.15
Farenheit (°F): F ≡ (9/5)C + 32
Rankine (°R): R ≡ (9/5)K = F + 459.67
Force
SI Units: newton (N), defined as kg·m/s².
dyne (dyn): 1e5 dyn ≡ 1 N
pound-force (lbf): 1 lbf ≡ 4.4482216152605 N
poundal (pdl): 1 pdl ≡ 1 lb·ft/s² ≡ 0.138254954376 N
relativistic limit: c⁴/(4G) = 3.0257e43N, uncertainty 5
Pressure
SI Unit: pascal (Pa), defined as N/m² ≡ kg/(m·s²)
atmosphere (atm): 1 atm ≡ 101.325 kPa = 760 Torr
bar (bar): 1 bar ≡ 1e6 dyn/cm² ≡ 0.1 MPa
barye (Ba): 1 Ba ≡ 1 dyn/cm² ≡ 0.1 Pa
pounds per square inch (psi): 1 psi ≡ 1 lbm/in² = 6.894757293 kPa
thousand pounds per square inch (ksi): 1 ksi ≡ 1000psi = 6.894757293 MPa
Torr (Torr): 760 Torr = 1 atm = 101.325 kPa
Energy
SI Unit: joule (J), defined as N·m = kg·m²/s².
British thermal unit (Btu): 1 Btu ≈ 1.054kJ (definitions vary)
calorie (cal): 1 cal ≡ 4.184 J (thermochemical; other calories exist)
Calorie (Cal): 1 Cal ≡ 1 kcal ≡ 4.184kJ (thermochemical)
electron-volt (eV): 1 eV ≡ 1 V·e = 1.60217653e-19 J (uncertainty 14)
erg (erg): 1 erg ≡ 1 g·cm/s² ≡ 1e-7 J
foe (foe): 1 foe ≡ 1e51 erg ≡ 1e44 J
foot-pounds (ft·lbf): 1 ft·lbf ≡ 1.3558179483314004J
watt-hour (Wh): 1 Wh ≡ 3600 J
Power
SI Unit: watt (W), defined as J/s = kg·m²/s³.
ergs per second (erg/s): 1 erg/s ≡ 1e-7 W
foot-pounds per second (ft·lbf/s): 1 ft·lbf/s = 1.3558179483314004 W
horsepower (hp): 1 hp ≡ 550 ft·lbf/s ≡ 745.69987158227022 W (mechanical)
relativistic limit: c⁵/(4G) = 9.0708e51 W, uncertainty 1
Electric Current and Field
SI Unit: ampere (A)
coulomb (C): 1 C ≡ 1 A·s
electrostatic unit (esu): 1 esu ≡ 1/(2997924580) C = 3.33564095198152e-10 C [stat-coulomb (statC), franklin (Fr)]
elementary charge (e): 1 e = 1.60217653e-19 C, uncertainty 14
farad (F): 1 F ≡ 1 C/V ≡ 1 s⁴·A²/(m²·kg)
ohm (Ω): 1 Ω ≡ 1 V/A ≡ 1 m²·kg/(s³·A²)
statvolt (statV): 1 statV ≡ 1 erg/esu ≡ 299.792458 V
volt (V): 1 V ≡ 1 J/C ≡ 1 W/A ≡ 1 m²·kg/(A·s³)
Magnetic Field
SI Unit tesla (T)
permeability of free space (μ_0): μ_0 ≡ 4π/10^7
Area
SI Unit: square meter, m²
square centimeter (cm²): 1 cm² ≡ 1e-4 m²
square inch (in²): 1 in² ≡ 6.4516 cm² ≡ 6.4516e-4 m²
square foot (ft²): 1 ft² ≡ 144 in² ≡ 0.09290304 m²
square mile (mi²): 1 mi² ≡ 2.589988110336 km² ≡ 2.589988110336e6 m²
hectare (ha): 1 ha ≡ 1e-2 km² ≡ 1e4 m²
Volume
SI Unit: cubic meter, m³
cubic centimeter (cm³): 1 cm³ ≡ 1 mL ≡ 1e-6 m³
cubic inch (in³): 1 in³ ≡ 16.387064 cm³
liter (L): 1 L ≡ 1 dm³ ≡ 0.001 m³
Velocity
SI Unit: meters per second, m/s
speed of light: c ≡ 299792458m/s
kilometer per hour(km/h)-->1km/h = 0.278m/s
Acceleration
SI Unit: meter per second squared, m/s²
feet per second squared (ft/s²): 1 ft/s² ≡ 0.3048 m/s²
standard gravity: 1 gee ≡ 9.80665 m/s² = 32.1740486 ft/s²
Density
kiolometers per cubic meter (kg/m³)
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Posted: Thu Jun 15, 2006 7:57 pm
shouldn't there be one for 10^0==E0==(starting unit or base unity) on the metric unit conversion index??
it just seemed odd that it jumed from E-1 to E1. and it allows for one to see what each one stands for such as meter/leter/gram. also a index into what each of them is used for like meter for leigth and leter for volume and gram for mass.
it seems layman but this is a private guild so anyone can view it, and if one doesn't understand some of the terms it may help that person out.
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Posted: Fri Jun 16, 2006 10:43 am
torasenshie shouldn't there be one for 10^0==E0==(starting unit or base unity) on the metric unit conversion index?? it just seemed odd that it jumed from E-1 to E1. and it allows for one to see what each one stands for such as meter/leter/gram. also a index into what each of them is used for like meter for leigth and leter for volume and gram for mass. it seems layman but this is a private guild so anyone can view it, and if one doesn't understand some of the terms it may help that person out. Anything to the power of 0 is 1 and it doesn't come with a prefix, as for meter/litre (you mispelled litre)/ gram... I could do that. There is one thing that concerns me hwr, have we decided to use metric? there are a lot of people who've joined the guild but who live in the states, so I'm wondering, how do you guys learn physics?
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Posted: Fri Jun 16, 2006 11:16 am
I'm British so I have a hacked metric/Imperial system for day-to-day life; but physics was always in metric.
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Posted: Fri Jun 16, 2006 7:36 pm
[ Message temporarily off-line ]
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Posted: Fri Jun 16, 2006 7:45 pm
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Posted: Sat Jun 17, 2006 8:02 am
yah I don't really understand what they are trying to do with the Imperial system the conversions are so... not nice round numbers. So tell ya what, we'll keep it metric, and ppl can learn it if they wish.
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Posted: Sat Jun 17, 2006 9:14 am
Gaia should definitely have better formatting for the posts, although maybe that would be too much to ask
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Posted: Sat Jun 17, 2006 5:20 pm
Some notes:
1. These are more properly called initialisms rather than acronyms, although that's a bit of a pedantic point that almost nobody would actually care about.
2. EM is a common shorthand for electromagnetism or electromagnetic.
3. The Celsius scale has a 273.15 unit difference with kelvin, rather than 273.16.
4. Unlike all other SI units, the base units for mass is the suffixed unit kilogram rather than the expected gram.
5. Why bother listing the suffixed units like the millimeter or megapascal? The suffixes are already given. Instead, there are other units not listed that are still used in physics. For example, the cgs system is still popular in electromagnetism, with its dynes, ergs, etc.
6. Some coverage of U.S. customary units may be a good thing, since some of them are very much in use in engineering fields. For example, measuring strength of materials in terms of pounds per square inch (psi) or kilopsi (ksi) is fairly common in materials science and engineering.
If you have no objections to this, I can simply make those changes myself (except probably #1). I would have done so already, but it would be bad form without asking first.
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Posted: Sat Jun 17, 2006 5:41 pm
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Posted: Sat Jun 17, 2006 7:33 pm
VorpalNeko Some notes: 1. These are more properly called initialisms rather than acronyms, although that's a bit of a pedantic point that almost nobody would actually care about. I didn't really call them anything VorpalNeko 2. EM is a common shorthand for electromagnetism or electromagnetic. 3. The Celsius scale has a 273.15 unit difference with kelvin, rather than 273.16. off by 0.01 ~ that's hilarious. VorpalNeko 4. Unlike all other SI units, the base units for mass is the suffixed unit kilogram rather than the expected gram. I started that way, but then decided it would be more repetitive if I went by order of magnitude (cause I was writing it up one by one so I didn't wanna put any brainpower into it). You can change them hwr, go ahead, do whatever you want with it, kill yourself, I already spent too much time on writing it up. It's not really written in stone, it's meant to be improved. VorpalNeko 5. Why bother listing the suffixed units like the millimeter or megapascal? The suffixes are already given. Instead, there are other units not listed that are still used in physics. For example, the cgs system is still popular in electromagnetism, with its dynes, ergs, etc. I dunno, I was being a**l, change it. VorpalNeko 6. Some coverage of U.S. customary units may be a good thing, since some of them are very much in use in engineering fields. For example, measuring strength of materials in terms of pounds per square inch (psi) or kilopsi (ksi) is fairly common in materials science and engineering. good idea, that should be in there. VorpalNeko If you have no objections to this, I can simply make those changes myself (except probably #1). I would have done so already, but it would be bad form without asking first. I have no objections.
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Posted: Sun Jun 18, 2006 12:20 am
I've made a revision, but ran out of steam in the middle of it. I'll finish it later. A Lost Iguana Oh, useful links. http://en.wikipedia.org/wiki/Atomic_units http://en.wikipedia.org/wiki/Planck_units However, it is not clear whether the Planck units are standardized. There are at least four possible definitions, starting from c = 1: either h = 1 or h/2π = 1, and either G = 1 or 8πG = 1.
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Posted: Sun Jun 18, 2006 4:52 pm
VorpalNeko: I love how you carry some of the conversions to 15 decimal places. Ps. how do you do the formatting? ie, the superscripts, and the defined as symbol.
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Posted: Tue Jun 20, 2006 7:45 pm
poweroutage VorpalNeko: I love how you carry some of the conversions to 15 decimal places. Eh, most of them are a matter of definition, so it is a matter of copy and paste when doing so on a computer. I figured that the reader can decide how many digits are necessary based on the use they are put for, and rounding them all to some specific value would be troublesome anyway. Just be glad that I did not go completely overboard on exactness, e.g., 1290320000 psi ≡ 8896443230521 N (that works, but has no decimal representation). Heh. Quote: Ps. how do you do the formatting? ie, the superscripts, and the defined as symbol. There are a variety of ways. If you running Windows, the easiest one is character map (run charmap.exe).
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Reply
