粗糙平面上的物体在外力作用下做恒定加速度运动的极值问题,可以应用摩擦角和全反力的方法进行图解分析。题目如图1所示,在水平面上静放一重为mg的物体,认为物体与水平面间的最大静摩擦因数和动摩擦因数相同为μ,现用力F拉物体。若要使物体在水平面上以加速度a做匀加速运动,求拉力F的最小值。解析如图2(a)所示,F_φ为物体受到的支持力N和滑动摩擦力F的合力,称为接触面对物体的全反力,φ为全反力F_φ与竖直方 Rough objects on the plane under the action of external force to do the constant acceleration of the extreme value of the problem, you can apply the friction angle and total reaction force graphical analysis. The subject is shown in Figure 1, in the horizontal plane on the weight of a static object, that the maximum static friction coefficient between the object and the horizontal and dynamic friction factor is the same μ, the force F pull the object. To make the object in the horizontal plane with acceleration a uniform acceleration, find the minimum value of the tension F. As shown in Figure 2 (a), F_φ is the resultant force of the support force N and the sliding friction force F, which is called the total reaction force of the contact surface on the object, and φ is the total reaction force F_φ and the vertical