1. Topic 4 Who is this guy Newton?

2. Isaac Newton

3. Aristotle BC 384-322

4. The heavenly realm aether

5. Galileo Galilei (1564-1642)

7. Galileo’s Principle of Inertia The natural state of a moving body is to continue moving in a straight line.

9. Why ?

11. Law I Every body perseveres in its state of being at rest or of moving uniformly straightforward, except insofar as it is compelled to change its state by forces impressed. p. 117- text ( Law of Inertia)

12. Law II A change in motion is proportional to the motive force impressed and takes place along the straight line in which that force is impressed. p. 117- text

13. What’s Momentum? Momentum is mass times velocity of an object. p = mv

14. Law III To any action there is always an opposite and equal reaction; in other words, the actions of two bodies upon each other are always equal and opposite in direction. p. 117- text

16. So mass is not weight? You need the mass of an object to get it’s weight. Mass is the amount of matter in an object, while weight is the force acting on that object’s mass… as if it were accelerating to the center of the earth. Yes!

19. Recall Newton’s 2 nd Law

20. Descartes’ Book on motion: Principles of Philosophy Newton’s Book on motion: Mathematical Principles of Natural Philosophy