1. 講者： 許永昌 老師 1

2. Contents 2

3. Action I (interacting objects) ( 請預 讀 P183~P185) Purpose: Identify force pairs Actor and Objects: One student. A spring. Two magnets. Action: Pull the spring. Push two magnets together. Tell us your feeling. 3

4. Interaction diagram ( 請預讀 P186~P187) Please read the TACTICS Box 7.1 4 denotes the force exerted by A on B.

5. Propulsion ( 請預讀 P187~P189) It is the force that a system with an internal source of energy uses to drive itself forward. Quizzes: The propulsion force on a car is due to ______. How can we be “pushed” by a friction force? Hint: Imagine what would happen on a frictionless surface. 5

6. Action II (interaction diagrams) Purpose: Exercises of interaction diagrams. Identify the internal forces pair and external force. The concept of System and Environment. Objects: Two boxes. Actions: Following the steps shown in TACTAICS BOX 7.1 to draw the interaction diagrams and free-body diagrams. The internal interactions in case 2 if we choose these two boxes as a system. 6 (1)(2)

7. Homework Student Workbook 7.1 7.3 7.7 7

8. Newton’s 3 rd Law of Motion ( 請預讀 P189~P194) 8

9. Exercises 9

10. Homework Student Workbook 7.8 7.10 P7-6 全 10

11. Ropes and Pulleys ( 請預讀 P194~P198) Cases: 1. 2. 11 (1)Draw the interaction diagram (2)Focus on the pulley with a small piece of rope, you will find that (3)If both the rope and the pulley are massless, T l =T r. ( 三個向量平行嗎？ )

12. Exercises Student Workbook P7-7. What is tension at the point connects the string and the block? 12 mBmB Pull with tension T 1. T 2 =? msms frictionless

13. Examples of Interacting-Objects Problems ( 請預讀 P198~P202) Example 7.7 (P198) 13 請試著用 P192 的 Strategy 7.1 想這些例子。

14. Homework Student Workbook 7.23 7.24 7.27 Textbook 7.8 7.12 7.17 7.29 7.43 請將 Terms and Notation 製成卡片。 14