### Lecture 13: Universal gravitation

**Objectives:**In this lecture, students will learn to

- state Kepler's Laws of planetary motion
- formulate Newton's law of universal gravitation
- relate the free-fall acceleration to mass and radius of a celestial body
- explain satellite motion in terms of circular motion under the influence of gravity
- derive Kepler's 3rd law for a circular orbit

**Lecture Notes:**

- Powerpoint: lec13.pptx
- Pdf (recommended for printing): lec13.pdf

**Videos:**

Introduction | lec13_1.mp4 | |

History and Kepler's Laws of planetary motion | lec13_2.mp4 | with captions |

Kepler's Laws Simulation | lec13_3.mp4 | with captions |

Newton's law of Universal Gravitation | lec13_4.mp4 | with captions |

Free-fall acceleration | lec13_5.mp4 | with captions |

Satellite motion and Kepler's 3rd law | lec13_6.mp4 | with captions |

Breaking News: Nobel Prize in Physics 2017 for observation of Gravitional Waves | Powerpoint slides with many links | |

2 minute video explanation of principle of LIGO detector (mp4) | ||

For your interest: | Einstein's Messengers (mp4) 20 minute video by the NSF |

**Homework assignment:** HW #13