2. Newton ’ s Law of Universal Gravitation Dan Li SUNY-Stony Brook 12/09/2002

3. Outline Who Found It? The Statement of the Law Gravity Near the Earth ’ s Surface Geophysical Applications Satellites

4. Who Found It?

5. The Statement of the Law Magnitude: Every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. Direction: This force acts along the line joining the two particles.

6. Gravity Near the Earth ’ s Surface

7. Some Geophysics

8. Some Geophysics: Applications Variation in g: Gravity Anomalies To investigate the structure of the Earth ’ s crust mineral deposit oil exploration Some examples mineral deposit oil exploration

9. Satellites What keeps a satellite up? Its high speed How they move?

10. Moon: Special Satellite

11. Earth: the Satellite of the sun

12. Summary a force “ acting at a distance ” even though there is no contact a useful tool to explore in space

13. Thank you!