# Units, Conversions, and Physical Constants

- Page ID
- 11735

## 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