实际机械往往包含了多种简单的机械,形成机械的组合.求解机械组合的问题,应采用先分解后综合的方法,即先将组合体分解成若干个单一的简单机械,分别对简单机械运用物理规律,然后根据各简单机械之间的关系,将各部件综合成为一个整体,以获得问题解.一、杠杆与杠杆的组合例1 一个成年人和一个小孩都要过河,一个从河的左岸到右岸,另一个则相反.两岸各有一块木板,但是每块木板都略短于河宽.试提出一种方法,以保证成年人和小孩都能平安地到 Actual machinery often contains a variety of simple machinery, forming a combination of machinery. Solve the problem of mechanical combination, should be used after the first decomposition of the integrated approach, that is the first decomposition of the assembly into a number of single simple machinery, respectively, the use of simple machinery The laws of physics, and then according to the relationship between the simple machinery, the various components into a whole, in order to obtain a solution to the problem. First, the combination of leverage and leverage Example 1 An adult and a child must cross the river, one from the river The left bank is on the right bank, and the other is the opposite. There is a wooden board on each side, but each board is slightly shorter than the river. Try to propose a way to ensure that adults and children can safely reach