Geology Reference
In-Depth Information
Appendix: SI, c.g.s. and Imperial
(customary USA) units and
conversion factors
Imperial (USA)
Quantity
SI name
SI symbol
c.g.s. equivalent
equivalent
10
3
g
Mass
kilogram
kg
2.205 lb
Time
second
s
s
s
10
2
cm
Length
metre
m
39.37 in
3.281 ft
metre s
-
2
ms
-
2
10
2
cm s
-
2
=
10
2
gal
39.37 in s
-
2
Acceleration
gu
=
m
ms
-
2
10
-
1
milligal (mgal)
3.937
¥
10
-
5
in s
-
2
Gravity
gravity unit
megagram m
-
3
Mg m
-
3
gcm
-
3
3.613
¥
10
-
2
lb in
-
3
62.421 lb ft
-
3
Density
10
5
dyne
Force
newton
N
0.2248 lb (force)
Pa
=
Nm
2
10 dyne cm
-
2
=
10
-
5
bar
1.45
¥
10
-
4
lb in
-
2
Pressure
pascal
10
7
erg
Energy
joule
J
0.7375 ft lb
W
=
Js
-
1
10
7
erg s
-
1
0.7375 ft lb s
-
1
1.341
¥
10
-
3
hp
Power
watt
Temperature
T
°C*
°C
(1.8
T
+
32)°F
Current
ampere
A
A
A
Potential
volt
V
V
V
W=
VA
-
1
Resistance
ohm
W
W
10
2
W
cm
Resistivity
ohm m
W
m
3.281 ohm ft
S
=W
-
1
Conductance
siemens
mho
mho
siemens m
-
1
Sm
-
1
10
-
2
mho cm
-
1
0.3048 mho ft
-
1
Conductivity
Dielectric constant
dimensionless
10
8
maxwell
Magnetic flux
weber
Wb
=
Vs
T
=
Wb m
-
2
10
4
gauss (G)
Magnetic flux
tesla
density (
B
)
Magnetic anomaly
nT
=
10
-
9
T
gamma (
g
)
=
10
-
5
G
nanotesla
ampere m
-
1
A m
-
1
4
p
¥
10
-
3
oersted
Magnetizing field
(
H
)
(Oe)
H
=
Wb A
-
1
10
9
emu
(electromagnetic
unit)
Inductance
henry
henry m
-
1
4
p
¥
10
-
7
Hm
-
1
Permeability of vacuum (
m
0
)
1
Susceptibility
dimensionless
k
4
p
emu
Magnetic pole strength
ampere m
A m
10 emu
ampere m
2
Am
2
10
3
emu
Magnetic moment
ampere m
-
1
Am
-
1
10
-
3
emu cm
-
3
Magnetization (
J
)
* Strictly, SI temperatures should be stated in kelvin (K = 273.15 + °C). In this topic, however, temperatures are given in the more familiar
Centigrade (Celsius) scale.
