物理学基础_-_Fundamentals_of_Physics_by_Halliday,_Resnick,_Walker_5_The_Laws_of_Motion.pdf

P U Z Z L E R P U Z Z L E R The Spirit of Akron is an airship that is more than 60 m long. When it is parked at an airport, one person can easily sup- port it overhead using a single hand. Nonetheless, it is impossible for even a very strong adult to move the ship abruptly. What property of this huge air- ship makes it very difficult to cause any sudden changes in its motion (Cour- tesy of Edward E. Ogden) web For more information about the airship, visit /us/blimp/ index.html c h a p t e r The Laws of Motion C h a p t e r O u t l i n e 5.1 The Concept of Force 5.5 The Force of Gravity and Weight 5.2 Newton’s First Law and Inertial 5.6 Newton’s Third Law Frames 5.7 Some Applications of Newton’s 5.3 Mass Laws 5.4 Newton’s Second Law 5.8 Forces of Friction 110 5.1 The Concept of Force 111 n Chapters 2 and 4, we described motion in terms of displacement, velocity, Iand acceleration without considering what might cause that motion. What might cause one particle to remain at rest and another particle to accelerate? In this chapter, we investigate what causes changes in motion. The two main factors we need to consider are the forces acting on an object and the mass of the object. We discuss the three basic laws of motion,