1. Newton’s Law of Universal Gravitation

2. What do we know about gravity?

6. We can conclude: the higher the mass the more gravity

7. Newton Said: Everything has gravity! – It is in proportion to the mass of the object

8. Mass Affecting Gravity

9. Distance Affecting Gravity

10. Universal Gravitation Constant

11. Example: Determine the force of gravitational attraction between the earth (m = 5.98 x 10 24 kg) and a 70-kg physics student if the student is standing at sea level, a distance of 6.38 x 10 6 m from earth's center.

12. How is gravity affected if the student moves further away from the earth?

13. Suppose that two objects attract each other with a gravitational force of 16 units. If the distance between the two objects is doubled, what is the new force of attraction between the two objects?

14. If the distance is increased by a factor of 2, then force will be decreased by a factor of 4 (22). The new force is then 1/4 of the original 16 units.

15. Gravitational field patterns A gravitational field can be represented by lines and arrows on a diagram, in a similar ways to magnetic field lines.

16. Gravitational field Gravitational field is a vector, and any calculations regarding fields (especially involving adding the fields from more than one mass) must use vector addition.

17. Field around a uniform spherical mass

18. Field close to the earth’s surface

19. Uniform Circular Motion