处于平衡状态的杠杆，若有些条件发生改变，其平衡状态可能遭到破坏．对此，绝大多数学生会依据杠杆平衡条件进行定量推理，但这种解法较复杂．现举几例．巧妙灵活运用平衡知识可迅速准确地作出判断．例1如图1，在水槽的中央漂浮一只木球，槽底放在支架上且平衡，则正确是（） A lever in equilibrium may be destroyed if some conditions change. In this regard, the vast majority of students will conduct quantitative reasoning based on leverage balance conditions, but this solution is more complex. Here are some examples. Clever and flexible use of balance knowledge can make quick and accurate judgments. Example 1 As shown in Figure 1, float a wooden ball in the center of the sink. The bottom of the tank is placed on the support and balanced. The correct answer is ()