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Click on the link below to go to the type of physical constant of interest.
Conversion Factors Physical Constants
The Earth The Solar System
Densities Specific Heats Latent Heats
SOME BASIC CONVERSION FACTORS
1 in = 2.54 cm
1 mi = 1.609 km
1 m2 = 10.76 ft2
1 acre = 4.356 x 104 ft2
1 mi2 = 640 acres
1 m3 = 35.31 ft3
1 fluid gallon = 4 quarts = 8 pints = 128 ounces = 231 in3
1 kg = 0.06852 slugs
1 atomic mass unit = 1 amu = 1.661 x 10–27 kg
1 slug/ft3 = 515.4 kg/m3
1 year = 365.25 days = 3.156 x 107 s
1 ft/s = 0.3048 m/s
1 mi/h = 1.609 km/h = 0.4470 m/s
1 N = 0.2248 lb
1 dyne = 1 x 10–5 N
1 lb/in2 = 6.805 x 10–2 atm = 6.895 x 103 Pa
1 Pa = 1.450 x 10–4 lb/in2
1 British thermal unit = 1 Btu = 777.9 ft lb = 1055 J
1 erg = 1 x 10–7 J
1 ft lb = 1.356 J
1 calorie = 1 cal = 4.186 J
1 kilowatt hour = kW h = 3.600 x 106 J
1 electron-volt = 1 eV = 1.602 x 10–19 J
1 horsepower = 1 hp = 2545 Btu/h = 745.7 W
GENERAL PHYSICAL CONSTANTS
Acceleration due to gravity at the earth’s surface: g = 9.8 m/s2
Speed of sound in air: vair = 331 m/s = 1090 ft/s
Speed of sound in water: vwater = 1460 m/s = 4790 ft/s
Atmospheric pressure at the earth’s surface: patm = 1.01 x 105 Pa
Avogadro’s number: NA = 6.02 x 1023
Universal Gas Constant: R = 8.31 J/(mole K)
Speed of light in a vacuum: c = 3.0 x 108 m/s
THE EARTH
mass: ME = 5.98 x 1024 kg
average radius: RE = 6.37 x 106 m
free-fall acceleration at surface: g = 9.8 m/s2
standard atmospheric pressure: patm = 1.01 x 105 Pa
escape speed: vesc = 1.12 x 104 m/s
THE SOLAR SYSTEM
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Body
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Mass (kg)
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Ave. Radius (m)
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Ave. Distance from Sun (m)
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Mercury
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3.34 x 1023
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2.45 x 106
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5.79 x 1010
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Venus
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4.87 x 1024
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6.05 x 106
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1.08 x 1011
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Earth
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5.98 x 1024
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6.37 x 106
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1.496 x 1011
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Mars
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6.43 x 1023
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3.37 x 106
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2.28 x 1011
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Jupiter
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1.90 x 1027
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6.97 x 107
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7.78 x 1011
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Saturn
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5.69 x 1026
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5.82 x 107
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1.43 x 1012
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Uranus
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8.69 x 1025
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2.59 x 107
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2.87 x 1012
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Neptune
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1.03 x 1026
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2.45 x 107
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4.50 x 1012
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Pluto
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1.32 x 1022
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1.16 x 106
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5.91 x 1012
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Moon
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7.36 x 1022
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1.74 x 106
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—
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Sun
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1.99 x 1030
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6.96 x 108
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—
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DENSITIES (see the discussion of density)
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Material
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Density (kg/m3)
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Interstellar Space
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1 x 10-20
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Best laboratory vacuum
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1 x 10-17
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Air
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1.21
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Styrofoam
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100
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Ice
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917
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Pure Water
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1,000
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Sea water
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1,024
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Whole blood
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1,060
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Earth (average)
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5,500
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Aluminum (element, Al)
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2,700
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Copper (element, Cu)
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8,890
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Gold (element, Au)
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19,300
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Iron (element, Fe)
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7,870
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Mercury (element, Hg)
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13,600
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Steel
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7,860
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SPECIFIC HEATS (at constant pressure) (see the discussion of specific heat)
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Substance
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Specific Heat (J/kg·Co)
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air
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1005
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aluminum
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900
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carbon (diamond)
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507
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carbon (graphite)
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712
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copper
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387
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ethyl alcohol
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2450
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glass
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490 to 830
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gold
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130
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ice
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2,060
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iron (pure)
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460
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lead
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128
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marble
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863
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mercury
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138
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oxygen
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912
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salt (NaCl)
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864
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silver
|
235
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sodium
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1226
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steam
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2009
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sugar
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1147
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water
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4186
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zinc
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386
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LATENT HEATS AND PHASE CHANGES (see discussion of phase changes and latent heat)
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Substance
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Melting (oC)
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Lf (kJ/kg)
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Boiling (oC)
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Lv (kJ/kg)
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aluminum
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659
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399
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2,327
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10,530
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copper
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1,083
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207
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2,595
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4,730
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ethyl alcohol
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– 114
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108
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78.3
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855
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gold
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1,063
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64
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2,600
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1,577
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hydrogen
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– 259
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58.0
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– 253
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455
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iron
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1,535
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289
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2,735
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6,320
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lead
|
328
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23
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1,750
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859
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mercury
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– 39
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11
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357
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295
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nitrogen
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– 210
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25.7
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– 196
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200
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oxygen
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– 219
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13.9
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– 183
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213
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silicon
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1,410
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1,654
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2,355
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10,584
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silver
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962
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111
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1,950
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2,356
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water
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0
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335
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100
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2,272
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zinc
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420
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102
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907
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1,679
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