在物理学习中，经常碰到一些貌似相同的题型，我们称其为姐妹题．同学们在解答这类题时既要看到它们之间的貌似，又要注意区分它们之间的质异，这样才能避免机械套用解题方法的错误、下面请看压强类姐妹题．题１如图１，Ａ是一个全封闭的容器，顶面积大于底面积，其内装满某种 In physics learning, we often encounter some seemingly identical questions. We call them sister questions. When students answer such questions, they must not only see the similarities between them, but also must pay attention to distinguishing the differences between them, so as to avoid mistakes in the mechanical application of the problem solving method. Question 1 is shown in Figure 1. A is a fully enclosed container with a top area larger than the bottom area and filled with some