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LENGTH |
m |
meter |
|
km, (cm), mm,
μm, nm
|
1 inch = 25.4 mm
1 foot = 305 mm
1 yard = 0.915 m
1 mile = 1.609 km |
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MASS |
kg |
kilogram |
g (gram) |
1 ton = 1000 kg
1 ounce = 28.35 g
1 pound = 454 g
1 kip = 454 kg
1 tom = 1016 kg |
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TIME |
s |
second |
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| ms (millisecond), minute, hour |
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TEMPERATURE |
oK |
degree kelvin |
|
1 deg C (celsius) = 1 deg K
N oC = N + 273.15oK
1 deg F = 5/9 deg C
N oF = 5/9 (N- 32)oC |
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LUMINOUS INTENSITY |
cd |
candela |
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PREFIXES
TO UNITS
- Multiples and Submultiples
| Fraction =
Name, Abbreviation |
(10-1
= deci,d)
(10-2 = centi,c)
(10-3 = milli,m)
(10-6 = micro,µ)
(10-9 = nano,n)
(10-12 = pico,p) |
(10 = deca, da)
(102= hecto, h)
(103= kilo, k)
(106= mega, M)
(109= giga, G)
(1012= tera, T) |
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DERIVED UNITS |
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AREA |
m2 |
meter squared |
square with sides of unit length
|
1 mm2 = 10-6
m2
1 ha (hectare) = 104 m2
1 km2 = 106 m2 |
1 ft2
= 0.093 m2
1 acre = 0.405 ha
1 mile2 = 2.59 km2 |
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VOLUME |
m3 |
cubic meter |
cube with sides of unit length
|
1 litre = 10 dm3
= 10-3 m3
1 cm3 = 10-6 m3 |
1 ft3
= 0.028 m3
1 gallon = 4.5461 |
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DENSITY |
kg/m3 |
kilogram per cubic meter |
unit mass per unit volume
|
1 g/cm3
= 1000 kg/m3
1 lb/in3 = 27.68 g/cm3
1 lb/ft3
= 16.019 kg/m3 |
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SURFACE DENSITY |
kg/m2 |
kilogram per meter squared |
unit mass per unit area
|
| 1 lb/ft2 = 4.882 kg/m2 |
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VELOCITY (LINEAR) |
m/s |
meter per second |
| unit length movement in unit time |
1 km/h = 0.278 m/s
1 ft/min = 0.005 m/s
1 ft/s = .305 m/s
1 mph = 1.609 km/h
1 knot = 1.853 km/h |
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ACCELERATION
(LINEAR) m2 |
meter per second squared |
unit velocity change in unit time
|
| 1 ft/s2 = 0.305 m/s2 |
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FORCE |
N |
newton |
kN, MN |
causing unit acceleration of unit
mass
|
1kbf = 4.448 N
1 kgf = 9.807 N
1 dyn = 10-5
N |
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WORK, ENERGY |
J (N m) |
joule |
|
unit force acting over unit
length
|
1 Wh= 3600 J
1 kWh = 3600 kJ
1 erg = 0.1 µJ
1 cal = 4.187 J
1 kcal = 4187 J
1 m kgf = 9.807 J
1 Btu = 1055.06 J
1 therm = 105.506 MJ
1 hp-h = 2684.5 kJ
1 ft lbf = 1.3556 J |
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POWER or ENERGY FLOW
RATE
unit energy spent in unit time |
W (J/s)
|
watt
megawatt
kilowatt |
| |
1 erg/s = 0.1
μW
1 cal/s = 4.187 W
1 kcal/h = 1.163 W
1 hp (metric) = 735.5 W |
1 Btu/h = 0.293 W
1 ton refrig = 3.516 kW
1 ft lbf/s = 1.356 W
1 hp = 745.7 W |
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DENSITY OF ENERGY
FLOW RATE (INTENSITY) |
W/m2 |
watt per meter squared |
unit energy flow rate through
unit area
|
kW/m2
µW/m2
MJ/m2
day
1 Btu/ft2h = 3.155 W/m2
1 kcal/m2h = 1.163 W/m2
1 cal/cm2h = 1langley/h = 41.87
kJ/m2 = 11.63 W/m2 |
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PRESSURE, STRESS |
N/m2 (pascal) |
newton per meter squared |
unit force acting on unit area
|
kN/m2,
MN/m2
1 bar = 100 kN/m2
1 m bar = 100 N/m2
1 kgf/cm2 = 98 kN/m2
1 kgf/m2 = 9.8 kN/m2
1 atmosphere = 101.32 kN/m2
1 m water guage = 9.8 kN/m2
1 lbf/in2
= 6895 N/m2
1 lbf/ft2
= 47.88 N/m2
1 tonf/ft2 = 1.356 W
1 ft water guage = 2.99 N/m2 |
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THERMAL CAPACITY |
J/deg C |
|
|
energy required by body for unit
temperature increase
|
1 Btu/deg F = 4.187 J/kg deg C
1 kcal/deg C = 4187 J/deg C |
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SPECIFIC HEAT |
J/kg deg C |
J/m3 deg C |
|
heat flow rate through unit area
of unit thickness of substance with unit temperatures difference between the two faces
|
1 Btu/lb deg F = 4.187 J/kg deg C
1 Btu/ft3 deg F = 67 kJ/m3 deg C
1 kcal/kg deg C = 4.187 kJ/kg deg C
1 kcal/m3 deg C = 4.187 kJ/m3 deg C
1 kcal/l deg C = 4.187 MJ/m3 deg C |
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THERMAL
CONDUCTIVITY |
W/m deg C |
|
heat flow rate through unit ara
of unit thickness of substance with unit temperature difference between the two faces
|
1 Btu.in/ft2.h.deg F = 0.144 W/m deg C
1 kcal/m.h.deg C = 1.163 W/m deg C |
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THERMAL
TRANSMITTANCE |
W/m2 deg C |
|
heat flow rate through unit area
of body with unit difference in temperature of air on the two sides
|
1 Btu/ft2.h.deg F = 5.678 W/m2 deg C
1 kcal/m2.h.deg C = 1.163 W/m2 deg C |
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LATENT
HEAT, CALORIFIC VALUE |
J/kg, J/m3 |
|
change in energy content at
change of state, or heat produced by combustion (per uit mass or unit volume)
|
1 Btu/lb = 2326 J/kg
1 Btu/ft3 = 37.26 kJ/m3
1 Btu/gal = 232 kJ/m3 |
1 kcal/kg = 4187 J/kg
1 kcal/m3 = 4187 J/m3
1 kcal/l = 4187 kJ/m3 |
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LUMINOUS FLUX |
Lm |
Lumen |
cd.sr |
| emitted by unit intensity source
in unit solid angle |
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ILLUMINATION |
lx |
lux |
Lm/m2 |
unit flux incident on unit area
|
| 1 Lm/ft² = 10.76 lx |
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LUMINANCE |
cd/m2 |
(nit) |
|
unit intensity per unit area asb (apostilb)
1 cd/m2
= 3.14 asb
1 cd/ft2
= 10.76 cd/m2
1 ft lambert = 10.76 asb = 3.42 cd/m2 |
