1. Chapter 13 Gravitation In this chapter we will explore the following topics: -Newton’s law of gravitation that describes the attractive force between two point masses and its application to extended objects -The acceleration of gravity on the surface of the earth, above it, as well as below it. -Gravitational potential energy -Kepler’s three laws on planetary motion -Satellites (orbits, energy, escape velocity) (13-1)

2. m1m1 m2m2 (13-2)

3. m1m1 m2m2 F 12 F 21 r (13-3) m1m1 m2m2 r F1F1 m2m2 m1m1

4. m1m1 dm r (13-4)

5. (13-5)

6. y-axis (13-6)

7. m1m1 m2m2 r F1F1 m2m2 m1m1 (13-7)

8. r m (13-8)

9. (13-9)

10. mB v = 0 m v A (13-10)

11. Polaris Celestial sphere Rotation Axis of the Celestial sphere earth N S Star (13-11)

12. (13-12)

13. (13-13)

14. (13-14)

15. (13-15)