Phys 3, Section 2				October 11, 1996

GRAVITY

Law of Universal Gravitation:

G = 6.67 10-11 N-m2/kg2

Developers of Gravitational Theory:

• Ptolemy (Earth at center of universe)
• Copernicus (Sun at center of universe)
• Brahe & Kepler (Experimentalists)
• Newton (Law of Universal Gravitation given above)
• Einstein (General Relativity: gravity = acceleration)
  

Gravity Field of a Uniform Sphere:

Kepler's Laws:

1. Elliptical motion
2. Equal areas in equal times
3. Square-of-period over cube-of-average-radius of orbit is constant: T²/r³ = constant