Constants and Conversions [ Up ] [ What is Physics ] [ Brief History of Physics ] [ How Theories Develop ] [ Constants and Conversions ] [ Physics Symbols ]

## Constants

 Universal Gravitational Constant G 6.67 ´ 10-11 N m2/kg2 Ideal Gas (or Boltzmann’s) Constant k 1.38 ´ 10-23 Joule/K 8.62 ´ 10-5 eV/K Stefan-Boltzmann Constant s 5.67 ´ 10-8 W/m2 K4 Gas Constant R 8.31 J/mol K Avogadro’s Number NA 6.02 ´ 1023 molecule/mol Coulomb Force Constant k 9.00 ´ 109 N m2/C2 Fundamental Charge e 1.60 ´ 10-19 C Speed of Light in vacuum c 3.00 ´ 108 m/s Planck’s Constant h 6.626 ´ 10-34 J s Planck’s Constant/2p 1.055 ´ 10-34 J s Rydberg (Bohr atom) constant R 1.1 ´ 107 m-1

## Some Physical Properties

 Density of Water rH2O 1 g/cm3 1000 kg/m3 Speed of Sound in dry Air at 1 atm and 20°C 343 m/s in Water at 1 atm and 20°C 1460 m/s Earth’s Gravitational Acceleration g 9.81 m/s2 Earth’s Radius rE 6.37 ´ 106 m Earth’s Mass mE 5.98 ´ 1024 kg Earth-Sun Distance (mean) 1 AU 1.49 ´ 108 km Earth-Moon Distance (mean) 3.80 ´ 105 km Electron Rest Mass me 9.11 ´ 10-31 kg Proton Rest Mass mp 1.67 ´ 10-27 kg

## Some Unit Conversions

 1 mile = 1609 m 1 meter = 3.28 ft 1 in = 2.54 cm 1 mph = 0.447 m/s 1 day = 86400 sec 1 year = 3.16 ´ 107 sec p Radians = 180 degrees 1 mm Hg = 133 Pa 1 atm = 1.01 ´ 105 Pascals 1 N = 0.225 lb 1 kg weighs 2.21 lb 1 Horsepower = 746 W 1 Joule = 0.239 cal 1 eV = 1.60 ´ 10-19 J

Compiled by J. Brennan, DVC Physics Dept. 1988. Please inform me of errors.

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Last Updated 07/08/04 by JWB