Contents --- Newton's Law of Gravity

• Introduction
• Newton's Laws of Motion
  • Newton's 1st law: inertia
  • Newton's 2nd law: F = m×a
  • Newton's 3rd law: action = -reaction
  • Review Questions
• Universal Law of Gravity
  • Characteristics of Gravity---why it is the most important force in astronomy.
  • Review Questions
• Mass vs. Weight
  • Review Questions
• Inverse Square Law
• Gravitational Acceleration
  • Measuring the Mass of the Earth
• A Closer Look at Newton's Gravity
  • Occam's Razor and the Progress of Motion Laws
  • Nature of Gravity
  • Machine Universe
  • Material World
  • Review Questions
• Orbits
  • Centripetal Force
  • Measuring Planet and Star Masses
  • Orbital Speed
  • Escape Velocity
• Kepler's Third Law
  • Interplanetary Trips
• Tides
  • Tides Slow Earth Rotation
  • Tides Enlarge Moon Orbit
  • Tidal Effects Elsewhere
  • Review Questions