题目

将质量为m=lkg的物体静止放在水平面上，物体与水平面之间的动摩擦因数为=0．2．现对 物体施加一个方向不变的水平力F，其大小变化如下图所示，在3秒之内物体位移最大的力的图是（   ）  答案：B解析:略 —Why did you call the police?—I went back home and saw a fighting__________ near my house.A. breaking up B. breaking down C. breaking in D. breaking out