1. Lecture 11: Laws of motion

2. Newton’s 1 st Law: Inertia Matter resists motion If at rest, it will stay at rest If in motion, it will stay in motion Mass is a measure of inertia

3. Newton’s 2 nd Law An unbalanced force acts on objects equal to its mass and acceleration F = m X a F = force m = mass a = acceleration

4. Gravity All objects in the universe attract each other Gravity is a function of mass and distance More mass= more gravity More distance = less gravity

5. Weight and gravity The pull of gravity on Earth is 9.8m/s 2 Weight is mass X the pull of gravity (w=mg) Q: are weight and mass the same? Q: do we weigh the same on the moon as on earth?

6. Terminal velocity The maximum speed objects fall to earth is 200 mi/h or 320km/h How does the parachute slow the fall?

7. Newton’s 3 rd Law Forces act in pairs For every action force, there is an equal and opposite reaction force

8. Momentum = mass X velocity The greater the mass, the greater the momentum. Ex: semi trucks take longer to stop than cars. Q: will momentum be greater at more velocity?

9. Action and reaction force pairs