1. FORCES

2. Journal #59/24/07 What causes things to move or change motion? Give examples of the kinds of actions that change an object’s motion. For example, what made the air trolley move? What causes things to move or change motion? Give examples of the kinds of actions that change an object’s motion. For example, what made the air trolley move?

3. Force: a push or pull which may change the motion of an object SI unit of force: Newton (N) a push or pull which may change the motion of an object SI unit of force: Newton (N)

4. I. Types of forces: A. Contact Force: 1. the force of one object pushing or pulling another object by touching 2. Example: friction 1. a force which resists motion between two surfaces in contact with each other A. Contact Force: 1. the force of one object pushing or pulling another object by touching 2. Example: friction 1. a force which resists motion between two surfaces in contact with each other

6. B. Non-contact Force: 1. A force applied to an object (or body) by another body that is not in direct contact with it. B. Non-contact Force: 1. A force applied to an object (or body) by another body that is not in direct contact with it. I. Type of Forces (cont.)

7. 2. Example: gravity the force of attraction between two masses (most noticeably the attraction between an object and Earth)

8. I.Type of Forces (cont.) 3. Example: electromagnetic force the forces of attraction or repulsion between electric charges