1. Chapter 3 Newton’s 1st Law of Motion Inertia

2. Net Forces cause changes in motion

3. Get to it. Newton’s 1st Law! Every object continues in a state of rest, or in uniform speed in a straight line, unless acted on by a nonzero net force.

4. Break it down! Every object continues in a state of rest Things remain at rest (Static Equilibrium) Or in uniform speed in a straight line Constant speed in a straight line (Dynamic Equilibrium) Unless?????

5. NonZero Net Force!  F  0 Non Zero Not zero. Anything but zero. Net Force. Must have a net force acting on it. The sum of the forces must be something.

6. So What Stops Things? If an object keeps moving why can’t you throw a football forever? Why does the soccer ball stop rolling? Why does the book stop sliding across the table? Friction!!! - Sliding force.

7. Inertia Inertia: The ability of a body to resist changes to its state of motion. Inertia is mass.

8. Difference between Mass and Weight Mass: Scalar - Measured in Kilograms (Kg) The amount and kind of atoms that make up an object. Does not change with location Weight: Vector - Measured in Newtons (N) The force due to gravity. Changes if the amount of gravity changes.