1. The Three Laws

2. Galileo Rolled Cannon Balls Down Inclined Planes Concluded ∆v ~ ∆t Noticed that if the plane was level  ∆v = 0 Velocity would not change – coast Aristotle said it was natural for things to come to rest. Galileo said it was natural for things to keep moving.

3. Newton 1642-1727 Mathematical Genius Manic-Depressive No Social Life Invented Calculus Three Laws of Motion Gravitation, Light Universe

4. Three Laws and Gravity First Law: – An Object in Motion Tends to Continue in Motion Second Law: – Acceleration is proportional to Force – a ~ F – F = m ∙ a – Force equals mass times acceleration – newton = kg ∙ m/s 2 Third Law: – To Every Action, there is an opposite and equal reaction. (If I push you then you push me.) The force of gravity is proportional to your mass – F grav = mg Prob Set 8B