Lesson: Motion of Planets, Moons, and Satellites Physics • 9th Grade

In this lesson, we will learn how to describe the velocities and accelerations of planets, moons, and man-made satellites that are moving along circular orbits.

Lesson Plan

Objectives

Students will be able to

  • state the two main types of orbit: circular and elliptical,
  • recognize the two main types of orbits from diagrams,
  • recognize that if two objects (such as a star and a planet) are closer to each other, the force of gravity between them will be greater,
  • know that for an object in orbit, the force of gravity is always in the direction of that which itโ€™s orbiting,
  • know that for an object in a circular orbit, the force is always perpendicular to the velocity,
  • know that for an object in a circular orbit, the acceleration of the object is always in the direction of that which itโ€™s orbiting and always perpendicular to the velocity,
  • know that for an object in a circular orbit, the smaller its orbital radius, the greater its orbital speed,
  • know that for an object in an elliptical orbit, when it is closer to that which itโ€™s orbiting, its speed will be greater,
  • know that the period of a geostationary orbit must be 24 hours,
  • know that a geostationary satellite must orbit above the equator.

Prerequisites

Students should already be familiar with

  • what stars, planets, and moons are,
  • the basic structure of the solar system.

Exclusions

Students will not cover

  • calculating orbital speeds/periods ๏€ผ๐‘‡=2๐œ‹๐‘Ÿ๐‘ฃ๏ˆ,
  • any of Keplerโ€™s laws,
  • Newtonโ€™s law of gravitation ๏€ฝ๐น=๐บ๐‘€๐‘š๐‘Ÿ๏‰๏Šจ,
  • any centripetal force/acceleration calculations ๏€พ๐น=๐‘š๐‘ฃ๐‘Ÿ,๐‘Ž=๐‘ฃ๐‘Ÿ๏Š๏Šจ๏Šจ.

Lesson Video

Video Thumbnail
13:02

Lesson Explainer

Sample Question Videos

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