1. Chapter 5 Force and Motion - I 第5章 力與運動(一)

2. Chapter 5 Force and Motion - I
5-1 What is Physics?
5-2 Newtonian Mechanics 牛頓力學
5-3 Newton’s First Law
5-4 Force 力
5-5 Mass 質量
5-6 Newton’s Second Law
5-7 Some Particular Forces
5-8 Newton’s Third Law
5-9 Applying Newton’s Law

3. 5-1 What is Physics? Acceleration 加速度 Force 力 Dragster Quarterback 四分衛
Knock down 撞倒

4. 5-2 Newtonian Mechanics Isaac Newton (1642 – 1727)艾薩克．牛頓
Very high speed
Newtonian mechanics  Einstein’s special theory of relativity
Atomic scale
Newtonian mechanics  Quantum mechanics

5. 5-3 Newton’s First Law Frictionless surface 無摩擦面
Newton’s First Law of Motion
If no force acts on a body, the body’s velocity cannot change; that is, the body cannot accelerate.
In other words, if the body is at rest, it stays at rest. If it is moving, it continues to move with the same velocity.

6. A force on the standard kilogram gives that body an acceleration

7. 5-4 Force net force (淨力) or resultant force (合力 )
Principle of superposition for forces
Newton’s First Law of Motion
If no net force acts on a body, the body’s velocity cannot change; that is, the body cannot accelerate.
Inertial reference frame or Inertial frame慣性參考坐標系

8. Noninertial frame

9. 5-5 Mass
The mass of a body is the characteristic that relates a force on the body to the resulting acceleration.

10. 5-6 Newton’s Second Law Newton’s Second Law of Motion
The net force on a body is equal to the product of the body’s mass and its acceleration.
pound 磅 (lb) (1 lb = kg, ???)
slug 斯拉格（斯勒格、斯）
1 slug = kg

11. free-body diagram 自由體受力圖
external force 外力
internal force 內力

12. Sample Problem

13. Sample Problem

14. 5-7 Some Particular Force
Gravitational Force, Fg 重力
Weight, W 重量
Normal Force, FN 正向力
Friction (Frictional Force), f 摩擦力
Tension, T 張力

15. An equal-arm balance 等臂天平

16. A spring scale 彈簧秤
Apparent weight視重、視重量

17. Normal Force, FN 正向力

18. Friction, f 摩擦力

19. Tension, T 張力

20. 5-8 Newton’s Third Law
When two bodies interact, the forces on the bodies from each other are always equal in magnitude and opposite in direction.
Third-law force pair 第三定律力偶

22. Third-law force pair 第三定律力偶

23. Sample Problem

24. Sample Problem

25. 力圖

26. Sample Problem

27. Sample Problem

28. Sample Problem

29. Sample Problem

30. Sample Problem