# Orbital mechanics 1

4 articles
1 challenge
1 video
2 skills
1 talkthrough
How do planets move? An introduction to orbital mechanics and the work of Johannes Kepler.

ARTICLE

ARTICLE

### Problem solving with area and circumference of circles

PRACTICE PROBLEMS
Practice interesting area and circumference problems.

ARTICLE

CHALLENGE

ARTICLE

### Introduction to ellipses

VIDEO 14:14 minutes
Sal introduces ellipses and shows how their standard equation relates to their center and radii (ellipses have two radii: major and minor).

### Find the center and radii of an ellipse from its equation

PRACTICE PROBLEMS
Find the center and major and minor radius of an ellipse given its equation.

### INTERACT: Elliptical orbits

TALKTHROUGH
Click and drag either foci to change orbit. You can also mouseover the terms below for definitions.