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两个物块叠放在一起,依靠之间的静摩擦力一起运动,在什么条件下会出现相对运动?两个物块与压缩的弹簧接触,释放弹簧后,在什么条件下两物块分离?2013年全国卷二第25题、34题分别对此作了考查.其实这两类问题的分析方法是相通的,即寻找临界状态,采用隔离法分析判断.为突出问题主要方面,另举两例进行说明.一、“相对运动”问题分析例1(2009清华自主)如图1,质量为M的板置于水平地面上,其上放置一质量为m的物块,物块与板、板与地面间的动摩擦系数分别为μ1、μ2.当作用在板上的水平力F多大时,刚好
Two pieces stacked together rely on the static friction between the movement, under what conditions will appear relative movement? Two pieces of contact with the compressed spring, release the spring, under what conditions the two pieces of separation? 2013 National Volume II 25 questions, 34 questions were examined separately.In fact, the analysis of these two types of problems are interlinked, that is, to find the critical state, the use of isolation method analysis and judgment. To highlight the main aspects of the problem, the other two Example 1 “Relative Movement ” Problem Analysis Example 1 (2009 Tsinghua Autonomous) As shown in Figure 1, the plate of mass M is placed on a level ground, on which a block of mass m is placed, The dynamic friction coefficient between plate, plate and ground is respectively μ1 and μ2. When the horizontal force F acting on the plate is just enough