面对物理综合题，不少学生只能望“题”兴叹，一筹莫展．假如我们能扣准难点，分解拆零，把复杂问题分解为若干较简单的问题，然后分而治之，问题便迎刃而解．[现象]教师出示题目：一根长为L的轻细线将一小球悬于定点O的正下方，开始时小球静止在最低点A，如图1．现用木棰在A处 In the face of physics synthesis problems, many students can only hope to “problem” and sigh. If we can decimate difficulties, dismantle and unbundle, and decompose complex issues into simpler problems, then divide and conquer, the problems will be solved. [Phenomenon] The teacher produces the title: A light and thin line of length L suspends a ball directly under the fixed point O. At the beginning, the ball is still at the lowest point A, as shown in Figure 1. The current wooden plaque is in place A