1. Newton’s 1st Law
Ch. 4 Sec. 2

2. What it states…
An object at rest will remain at rest and an object in motion will remain in motion (at a constant speed in straight line) unless the object experiences an external force

3. Also known as… The Law of Inertia
Inertia= the tendency of an object to resist being moved or, if the object is moving, to resist a change in speed or direction.

4. Net force
Net force= the vector sum of all forces acting on an object

5. Examples

6. More examples using free body diagrams

7. Equilibrium The state in which the net force on an object is zero.
***Either no force or two balanced forces are required for equilibrium to occur!!! ***
p. 129 (read under equilibrium)

8. Science of seat belts https://www.youtube.com/watch?v=04gD8dCVbys