# Digital.Complex: Those damn Greek letters - Digital.Complex

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## Those damn Greek letters What they mean Rate Topic:     1 Votes //<![CDATA[ rating = new ipb.rating( 'topic_rate_', { url: 'http://www.digitalcomplex.org/index.php?s=58248e01b60732d52b7ca6df3662b46f&amp;app=forums&module=ajax&section=topics&do=rateTopic&t=470&md5check=' + ipb.vars['secure_hash'], cur_rating: 5, rated: 0, allow_rate: 0, multi_rate: 1, show_rate_text: true } ); //]]>

### #1 aotsukisho

•     • Group: Owner
• Posts: 2,523
• Joined: 18-October 05

Posted 06 April 2007 - 12:57 AM

I'm throwing this huge list of what all these single-letter/symbol variables all stand for. I have a physics midterm soon, and a reference to what all these things stand for will help me out a lot. For those of you in physics, you can help correct any mistakes I make, and add whatever symbols you're working with too.

Note that this isn't a complete list, because I'm only listing the symbols that I've encountered. I have placeholders for the entire Greek/Roman alphabet though, so I don't have to add lines in later.

```Α -
Β -
β - Relativity-related ratio (u/c)
Γ -
γ - Relativity constant (1/sqrt(1-(u^2/c^2)); γ>>1 implies 'relativistic speed' )
Δ - Difference of (final-initial)
δ - Impulse function (ie. δ(x)); deformation of an object under normal-axial loading (meter)
Ε - Youngs Modulus, Modulus of Rigidity (Newtons/meter^2 or Pascals)
ε - Normal Strain (unitless by definition: δ/L)
Ζ -
ζ - Damping ratio in a spring system
Η -
η - Performance (Desired output/required input: W[sub]net,out[/sub]/Q[sub]in[/sub])
Θ -
θ - Angular position, Angle (degrees)
Ι -
ι -
Κ -
κ -
Λ -
λ - Wavelength (meters)
Μ -
μ - Coefficient of friction (μ[sub]k[/sub])
Ν -
ν - Frequency (hertz, 1/sec); specific weight (1/ρ: meter^3/kilogram)
Ξ -
ξ -
Ο -
ο -
Π - Product operator
π - Mathematical constant (3.141592654...)
ϖ -
Ρ -
ρ - Density (kilograms/meter^3); Radius of Curvature, [(1+(dy/dx)^2)^(3/2)]/[d^2y/dx^2] (meters)
Σ - Summation operator
σ - Normal Stress (Newtons/meter^2 or Pascals)
ς -
Τ -
τ - Torque (newton-meters); Shear Stress (Newtons/meter^2 or Pascals)
Υ -
υ -
φ - Angle of Twist (radians)
Χ -
χ -
Ψ -
ψ -
Ω - Resistance (ohms)
A -
a - Linear acceleration (meters/second^2)
B -
b -
C -
c - Speed of light constant (299,792,458 meters/second)
D -
d - Derivative (ie. dx/dt), Distance (meters)
E -
e -
F - Force (newtons)
f -
G - Gravitational constant (6.67E-11 newton-meters^2/kilogram^2); Shear Modulus ()
g - Gravitational acceleration (9.81 meters/second^2 downwards)
H -
h - Plancks Constant (6.62606896E-34 joule-seconds)
I - Moment of Inertia (kilograms/meter^2), Electric current (amperes)
i -
J - Polar Moment of Inertia (kilograms*meters^2)
j - Imaginary number (sqrt(-1))
K - Kinetic energy of a system (joules)
k -
L - Length (meters)
l - Relativistic length (meters)
M -
m - Mass (kilograms)
N - Newtons (kilogram-meters/second^2)
n -
O -
o -
P - Mechanical Power (Newton-meters), Electrical Power (amps^2-ohms, volts^2/amp)
p - Momentum, Pressure (Newton/meters^2)
Q - Electrical Charge (coulombs, ampere-seconds, farad-volts)
q -
R - Ideal Gas Constant ([kiloPascals*kilogram]/[meter^3*Kelvin])
S - Relativistic Inertial Reference Frame (nonmoving compared to other reference frame, S')
s -
T -
t - Time (seconds; relativity special case t[sub]0[/sub] is 'proper time', ie. from inertial reference frame S, not S')
U - Gravitational potential energy of a system (joules)
u - Relativistic velocity between two inertial frames of reference (meters/second)
V - Electric potential (volts)
v - Linear velocity (meters/second)
W - Work (joules)
w -
X -
x - Horizontal Position (meters)
Y -
y - Vertical Position (meters)
Z -
z - Z-axis position (meters)```

0

### #2 Enoesiw

•    • Posts: 103
• Joined: 19-July 07

Posted 20 July 2009 - 10:44 PM

I added in 'nu'=frequency, 'P'=Mechanical/Electrical Power, 'Q'=Electrical Charge

Added in a bunch of ME terms.
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