Chapter Objectives

• Explain Newton's idea of why the apple falls to Earth.
• Explain why the moon does not fall to Earth.
• Explain how Earth is falling.
• State Newton's law of universal gravitation.
• Explain the significance of an inverse-square law.
• Explain the connection between gravitation and the idea that the universe may stop expanding and begin to contract.
• Describe the gravitational field outside Earth.
• Describe the gravitational field inside Earth.
• Explain why an astronaut in Earth orbit seems weightless even though there is a gravitational force.
• Explain ocean tides.
• Give examples of tides other than those in water.
• Describe black holes.

Chapter Terms:

• law of universal gravitation
• inverse-square law
• weightlessness
• spring tide
• neap tide
• gravitational field
• black hole
• Big Bang

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Chapter Formulas:

 

F =

G

m1m2 d2

 

Chapter Outline Framework:

• The Universal Law of Gravity
• The Universal Gravitational Constant, G
• Gravity and Distance; The Inverse Square Law
• Weight and Weightlessness
• Ocean Tides
  • Tides in the Earth and Atmosphere
  • Tides on the Moon
• Gravitational Fields
• Gravitational Field Inside a Planet
• Einstein's Theory of Gravitation
• Black Holes
• Universal Gravitation

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