第 1 5届全国中学生物理竞赛预赛试卷第 7题给出的参考答案很繁琐 ,若利用坐标变换来解此题 ,将变得十分简洁 .原题及简洁的解法如下 .[原题 ]1ｍｏｌ理想气体缓慢地经历了一个循环过程 ,ｐ-Ｖ图中这过程是一个椭圆 ,如图 1所示 .已知此气体若处在与椭圆中心Ｏ′点所对应的状态 The answer given in Question 7 of the 15th National Middle School Student Physics Competition Preliminary Examination Paper is very tedious. If you use coordinate transformation to solve this problem, it will be very concise. The original problem and concise solution are as follows. [original] 1mol ideal The gas slowly undergoes a cyclic process, which is an ellipse in the p-V diagram, as shown in Figure 1. It is known that this gas is in the state corresponding to the O’ point of the ellipse center.