Units, Conversions, and Physical Constants

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Units

Unit Abbreviation	Unit Name	Quantity	Base Units
m	Meter	Length	m
kg	Kilogram	Mass	kg
Pa	Pascal	Pressure	kg / (ms\(^2\))
s	Second	Time	s
N	Newton	Force	kgm / s\(^2\)
K	Kelvin	Temperature	K
Hz	Hertz	Frequency	1 / s
rad	Radian	Angle	1
J	Joule	Energy	kgm\(^2\) / s\(^2\)
W	Watt	Power	kgm\(^2\) / s\(^3\)
AU or au	Astronomical Unit	Length	See Conversions

Common Conversions

1m = 39.37 in = 3.281 ft = 1.094 yd

1 rad = 57.30\(^\circ\)

1\(^\circ\) = 0.01745 rad = \(\pi\) / 180

1 Pa = 9.869 x 10\(^{-6}\) atm

1 kg/m\(^3\) = 1000 g/cm\(^3\)

1 AU = 1.495 x 10\(^{8}\) km = 1.495 x 10\(^{11}\) km

1 year (yr) = 3.15 x 10\(^{7}\) s

1 million years (my or myr) = 3.15 x 10\(^{13}\) s

1 day = 86,400 s

1 hour = 3600 s

1 K = -273.15 C = -457.87 F

Physical Constants

Name	Symbol	Value
Acceleration due to Gravity	g	9.81 m/s\(^2\)
Universal Gravitational Constant	G	6.674 x 10\(^{-11}\) Nm\(^2\)/(kg\(^2\))
Speed of Light	c	2.98 x 10\(^{8}\) m/s
Mass of the Sun	M\(_{sun}\)	1.98 x 10\(^{30}\) kg
Radius of the Sun	R\(_{sun}\)	695700 km

*For Planet and Moon Information see the Other Section

Other

Guide to Greek Letters: Greek Alphabet

Power of 10 Prefixes (ex. kilo-): Metric Prefixes

Planetary Physical and Orbital Constants: Planets and Pluto Physical Characteristics

Selected Moon Planetary and Orbital Constants: Moon Physical Data Note: To get M by itself, just divide the GM number by the Gravitational Constant G

Common Formulas, Trigonometric Identities, Derivatives, and Integrals: Mathematical Formulas