1. Force

2. Something that changes the state of rest or the state of motion of an object. Can be a push or a pull Unit of measure Newtons N

3. Balanced Force Forces that do not change the motion or direction of an object. Net Force is 0 Example: When a book is on a table the book is not moving because the force of the table pushing up is equal to the force of gravity pulling down.

4. Unbalanced Force Forces that change the state of motion or direction of an object. Net Force is not 0 Example: When a book is pushed off the table the book falls to the floor because the pull of gravity is greater than any upward push.

5. Friction An unbalanced force that opposes motion between two surfaces.

6. Calculating Force Force = mass * acceleration F = ma Force is measured in Newtons (N) Mass is measured in kilograms (kg) Acceleration is measured in m/s 2