SAT2物理练习：What Are Forces.

　　SAT2物理对于中国学生来说也是相对比较简单的考试，因此选择的人数也比较多。今天就为大家整理了SAT2物理练习的内容：What Are Forces，希望对同学们备考有所帮助。

　　Whenever we lift something, push something, or otherwise manipulate an object, we are exerting a force. A force is dined very practically as a push or a pull—essentially it’s what makes things move. A force is a vector quantity, as it has both a magnitude and a direction. 　　In this chapter, we will use the example of pushing a box along the floor to illustrate many concepts about forces, with the assumption that it’s a pretty intuitive model that you will have little trouble imagining.　　Physicists use simple pictures called free-body diagrams to illustrate the forces acting on an object. In these diagrams, the forces acting on a body are drawn as vectors originating from the center of the object. Following is a free-body diagram of you pushing a box into your new college dorm with force F.

　　Because force is a vector quantity, it follows the rules of vector addition. If your evil roommate comes and pushes the box in the opposite direction with exactly the same magnitude of force (force –F), the net force on the box is zero.

　　以上就是关于SAT2物理练习——What Are Forces的介绍。同学们在备考过程中，一定要加强习题的练习。