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Reference Section - Physics
Air at rtp:
- Density: 1.20 kg m -3
- Specific heat capacity: 1.00 x 103 J kg -1 K -1
- Speed of sound: 343 m s -1
Water at rtp:
- Density: 1.00 x 103 kg m -3
- Ice: 0.917 x 103
- Specific heat capacity: 4.18 x 103 K kg -1 K -1
- Speed of sound: 1.26 x 103 m s -1
- Viscosity: 10-3 nu / Pa s
- Refractive index: H C 1.331, Na D 1.333, H F 1.31
- Surface tension water to air: 7.3 x 10 -2 N m -1
- Specific latent heat: 333.5 kJ kg -1 K -1
Earth:
- Mean Density: 5.49 x 103 kg m -3
- Mean radius: 6.37 x 106 m
- Mass: 5.97 x 1024 kg
- Atmospheric pressure at sea level: 1.01 x 105 Pa
- Thermal conductivity: air at 0 oC: 2.4 x 102 W m -1 K -1; water at 0 oC = 0.6 W m -1 K -1
- Mean earth - moon distance: 3.84 x 108 m
Physical constants:
- Gravitational acceleration, g: on Earth = 9.81 m / s2, on Moon = 1.67 m / s2
- Gravitational constant, G: 6.67 x 10 -11 N m2 kg -2
- Electron mass: 9.11 x 10 -31 kg
- Proton mass: 1.673 x 10 -27 kg
- Neutron mass: 1.675 x 10 -27 kg
- Speed of light, c: 3.00 x 108 m / s
- Universal gas constant: 8.31 J mol -1 K -1
- Boltzmann's constant: 1.38 x 10 -23 J / K
- Stefan-Boltzmann constant: 5.670 x 10 -8W m-2 K -4
- Avogadro's constant: 6.02 x 1023 mol -1
- Molar volume at stp: 2.241 x 10 -2 m3 mol -1
- Gas constant = 8.314 J K -1 mol -1
- Faraday constant: 9.649 x 104 mol -1
- Impedance of empty space, Zo = 376.7 ohms
- Speed of light, c: 2.998 x 108 m/s
- Wien's radiation law: lambdamax T = 2.898 x 10 -3 m K; vmax / T = 5.879 x 1010 s -1 K -1
- Rydberg's constant, Rinf = 1.0974 x 107 m -1
- Electron or proton charge, ± e: ± 1.602 x 10 -19 C
- Specific electron charge, -e / m: = -1.759 x 1011 C kg -1
- Planck's constant, h = 6.626 x 10 -34 J s;
- Reduced Planck's constant, h-bar = h / 2pi = 1.0546 x 10 -34 J s
- Fraunhofer lines wavelengths: Na D (yellow) 589.6 nm; 589.0 nm; H C (red) 656.3 nm; H F (blue-green) 486.1 nm
- Permittivity constant, epsilono: 8.854 x 10 -12 F / m, or 1 / (4pi eo) = 8.99 x 109 N m2 C -2
- Elementary charge, e: 1.60 x 10 -19 C
- Permeability constant, µo: 4pi x 10 -7 T m A -1, or 1.2566 x 10 -6 N / A2
- Electron volt, eV: 1.60 x 10 -19 J
- Unified atomic mass unit, 1 amu = 1.66 x 10 -27 kg
The Solar System:
Body
|
Orbital radius / m
|
Body radius / m
|
Mass / kg
|
Sun
|
-
|
6.96 x 108
|
1.99 x 1030
|
Mercury
|
5.79 x 1010
|
2.42 x 106
|
3.35 x 1023
|
Venus
|
1.08 x 1011
|
6.10 x 106
|
4.89 x 1024
|
Earth
|
1.50 x 1011
|
6.37 x 106
|
5.97 x 1024
|
Mars
|
2.28 x 1011
|
3.38 x 106
|
6.46 x 1023
|
Jupiter
|
7.78 x 1011
|
7.13 x 107
|
1.90 x 1023
|
Saturn
|
1.43 x 1012
|
6.04 x 107
|
5.69 x 1026
|
Moon
|
3.84 x 108
|
1.74 x 106
|
7.35 x 1022
|
Units:
Quantity
|
Unit
|
Base units
|
Common units
|
Capacitance
|
farad, F
|
kg -1 m -2 s4 A2
|
C / V
|
Electric charge, q
|
Coulomb, C
|
sA
|
-
|
Electric field, E
|
-
|
kg m2 s -3 A -2
|
N / C or V / m
|
Electric potential, V and emf
|
Volt, V
|
kg m2 s -3 A -1
|
J / C or W / A
|
Electric resistance, R
|
ohm
|
kg m2 s -3 A -2
|
V / A
|
Energy, E
|
Joule, J
|
kg m2 / s2
|
Nm
|
Force
|
newton, N
|
kg m / s2
|
-
|
Frequency, f
|
hertz, Hz
|
s -1
|
-
|
Magnetic field
|
tesla, T
|
kg s -2 A -1
|
Wb / m2
|
Magnetic flux
|
weber, Wb
|
kg m2 s-2 A -1
|
Vs
|
Power, P
|
watt, W
|
kg m2 / s3
|
J / s
|
Pressure, p
|
pascal, Pa
|
kg m -1 s -2
|
N / m2 or J / m3
|
Conversions
Length:
- 1 in. = 2.54 cm
- 1 m = 39.37 in = 3.281 ft
- 1 ft = 0.3048 m
- 12 in = 1 ft
- 3 ft = 1 yd
- 1 yd = 0.9144 m
- 1 km = 0.621 mi
- 1 mi = 1.6093 km
- 1 mi = 5280 ft
- 1 Angstrom = 10 -10 m = 0.1 nm
- 1 µm = 10 -6 m = 10 4 Angstroms
- 1 lightyear = 9.461 x 1015 m
- 1 nautical mile = 1.852 km
Area:
- 1 m2 = 104 cm = 10.76 ft2
- 1 hectare = 104 m2
- 1 acre = 0.4047 ha
- 1 ft2 = 0.0929 m2 = 1.44 in2
- 1 in2 = 6.452 cm2
- 1 m2 = 1000 x 1000 mm = 106 mm2
Volume:
- 1 m3 = 106 cm3 = 6.102 x 104 in3 = 264.2 gal
- 1 ft3 = 1728 in3 = 2.83 x 10 -2 m3
- 1 lt = 1000 cm3 = 1.0576 qt = 0.0353 ft3
- 1 ft3 = 7.481 gal = 28.32 lt = 2.832 x 10 -2 m3
- 1 lt = 1 dm3 = 1 m -3
- 1 gal (US) = 3.786 lt = 231 in3
- 1 gal (UK) = 4.546 lt
- 1 pt = 0.568 lt
Volumetric flow rate:
- 1 m3 / s = 2119 ft3 / min = 15860 gal / min
Pressure:
- 1 bar = 105 N / m2 = 105 Pa = 14.50 lb / in2
- 1 atm = 760 mm Hg = 76.0 cm Hg = 101.33 kPa
- 1 atm = 14.7 lb / in2 = 1.013 x 105 N / m2
- 1 Pa = 1 N / m2 = 1.45 x 10 -4 lb / in2
- 1 kPa = 0.14504 ft lb / in2 = 4.015 in H2O = 10 -2 bar = 7.501 mmHg
- 1 torr (mmHg) = 133.3 Pa
- 1 ft lb / in2 (p.s.i.) = 6.895 kPa
- 1 tonf ft -2 = 107.3 kPa
Mass:
- 1000 kg = 1 metric tonne (t)
- 1 slug = 14.59 kg
- 1 u = 1.66 x 10 -27 kg
- 1 lb = 0.4536 kg
- 1 kg = 1000 g = 2.4 lb
- 1 oz = 28.35 g
- 1 ton = 1.016 t
Density:
- 1 g / cm = 62.43 lb / ft3 = 103 kg / m3
- 1 kg / m3
- 1 lb ft -3 = 16.02 kg m -3
Temperature:
- 0 K = -273.71 oC
- 0 oC = 273.71 K = 32 oF
- 1 oC = 1.8 oF = 1 K (temperature difference)
- 1.8 K = 1 oR
Converting temperatures:
- oF = (1.8 x oC) + 32
- oC = (oF - 32) / 1.8
- K = oC + 273
Force:
- 1 N = 105 dyne = 0.22481 ft lb
- 1 ft lb = 4.448 N
- 1 pdl = 0.1383 N
- 1 dyne = 10 -5 N = 2.248 x 10 -6 ft lb
- 1 tonf = 9.964 N
Velocity:
- 1 mi / h (m.p.h.) = 1.47 ft / s = 0.447 m / s = 1.61 km / h
- 1 km / h = 0.2778 m / s
- 1 knot (UK) = 0.5148 m / s
- 1 m / s = 100 cm /s = 3.281 ft / s = 2.237 mi / h
- 1 mi / min = 60 mi / h = 88 ft / s
- 1 rev / min (r.p.m.) = 0.1047 rad s -1
Acceleration:
- 1 m / s2 = 100 cm / s2 = 3.2808 ft / s2
- 1 ft / s2 = 0.3048 m / s2 = 30.48 cm / s2
Time:
- 1 yr = 365 days = 3.16 x 107 s
- 1 day = 24 hr = 1.44 x 103 min = 86400 s
Energy:
- 1 J = 0.738 ft lb = 107 erg
- 1 cal = 4.186 J
- 1 Btu = 252 cal = 1.054 x 103 J
- 1 eV = 1.6 x 10 -19 J
- 1 u = 931.5 MeV
- 1 kWh = 3.60 x 106 J
Specific energy:
- 1 kJ / kg = 0.4299 Btu / lb
Specific heat capacity:
- 1 kJ / kg K = 0.2388 Btu / (lb oR)
Specific gravity = density of substance / density of water, as a ratio
Power:
- 1 hp = 550 ft lb / s = 0.746 kW = 746 W
- 1 W = 1 J / s = 0.738 ft lb / s
- 1 Btu / h = 0.293 W
- 1 kW = 1.3410 hp = 3414 Btu / h = 737.6 ft lb / s
Useful trigonometry:
pi = 3.14159
e = 2.71828
1 rad = 57.2958o
ln 2 = 0.693147
1n 10 = 2.30259
sin 0 = 0
cos 0 = 1
tan 0 = 0
sin 30o = 1/2
cos 30o = sqrt3 / 2
tan 30 = 1 / sqrt3
30o = (pi / 6) rad
sin 45o = sqrt2 / 2 = cos 45o
tan 45o = 1 = sin 90o
45o = (pi / 4) c
sin 60o = sqrt3 / 2
cos 60o = 1 / 2
tan 60o = sqrt3
60o = (pi / 3) c
cos 90o = 0
tan 90o = inf
90o = (pi / 2 )c
[ Back to Part 31 ]