We know that because they also have a writing which we can read, and it speaks of it as well as the archeological remains that show destruction.

他们有文字,所以我们能了解这些内容,手稿和古代遗址一起,诠释了那场劫难

耶鲁公开课 - 古希腊历史简介课程节选

So delta u is just equal to the work but we also know what happens T2 because the temperature is changing from T1 to T2.

所以Δu等于输出的功,但我们也知道它会发生,同时我们知道温度从T1变到。

麻省理工公开课 - 热力学与动力学课程节选