http://www.ck12.org Chapter 6. Universal Gravitation
CHAPTER
6 Universal Gravitation
Chapter Outline
6.1 Kepler’s Laws of Planetary Motion
6.2 UNIVERSALLAW OFGRAVITY
6.3 ORBITALMOTION
6.4 REFERENCES
We know that gravity is the force that keeps us from falling away from the surface of the Earth. The force of gravity
reaches a significant distance, though as the distance increases, the force decreases by the square of the distance.
However, Earth’s mass is so large, and its gravity so strong, that the force reaches beyond the surface and atmosphere
into space. The Gemini 4 flight of June 1965, NASA’s second manned space flight, circled the planet 66 times in
four days. Astronaut Edward H. White II was the first American to take a space walk, held in place in Earth’s orbit
because of the force of gravity.