So now if I look at my V1 over V2 to the gamma minus 1, that's T2 over T1.
于是把^=中2,的两个温度。
So, the first obvious one is to take V1 to V2 first with p constant. So take this path here.
从初态到末态可以有无数种路径2,甚至像这样,我们只研究两种。
Argv2 Let me go ahead and now run Arg V2 with nothing.
我们现在继续运行。
You might have already noticed that I'm using the classes V2 server so the syllabus is there, I'm going to go over the syllabus a little bit later, but the syllabus is available online.
你们可能已经注意到,我使用了班级服务器,所以课程大纲在这儿,虽然我待会儿会把这页内容翻过去,不过课程大纲已经挂在网上了
If you,or a friend of yours,wants to see this syllabus after the class,and you don't have one, it's on the Classes v2 server.
如果你或你朋友想在课后看看,但你没有多余的,可以在Classes,v2服务器上找到。
I put it up on the ClassesV2 not as part of the reading list but it's under Resources so you can read Kipling.
我把它放到V2类别2,并没有放到阅读列表里,而是在“资源“里,所以你可以阅读吉卜林的作品。
V3 Here's the V4 over V3, V1 oops, sorry. V2 over V1, this is equal to the inverse of this.
所以就是这里的V4除以,哦,对不起,V2除以,它是它的倒数。
p2 So they're both p2. external is p2 p2 V2 T2 and I have p2, V2, T2, on the other side.
都是2,这样末态是。
I'm going from V2 to V2 dv - what do you think this integral is? Right, W1 so this is easy part, zero here.
这样才保证了过程的可逆性,下面来计算,路径1的功。
V2 Now we could put stops here at V2, but this piston would just kiss the stops.
现在我们可以把挡板放在这里,这时体积是,活塞会刚好碰到挡板。
Every time you do the experiment T in equilibrium with the heat bath at T, v2 you'll get the same p2 and V2.
与热库相接触的每次实验中,达到热平衡后的温度都是,压强都是p2,体积都是。
log So that's just the log of V2 over V1.
因此就是。
V2 You could also do a different path.
再保持体积为。
And so we can write this, ln minus nRT log V2 over V1.
所以结果是,负的nRT除以。
I take V1 to V2 first, keeping the pressure constant at p1, then I take p1 to p2 keeping the volume constant V2 at V2. Let's call this path 1.
容易计算的路径,第一条路径,是首先保持压强不变,体积从V1压缩到。
V2 p1 times V2 minus V1. What that turns out to be, 0 this area right here. It's V1 minus V2 times p1.
第二步做的功是-pdV,积分从V2到,这部分积分出来是多少?应该是。
The ideal gas constant doesn't change, temperature doesn't change, and so v we just have minus nRT integral V1, V2, dV over V.
理想气体常数不变,温度也不变,因此,是负的nRT,积分从v1到v2,dv除以。
So, the work for this process is the integral, pdv or minus the integral, V1, V2, p dV.
此过程中的做功等于负的积分,从v1到v2,外部。
So on the p-V diagram, then, V1 V2 p1 p2 there's a V1 here a V2 here, a p1 here a p2 here.
在p-V图上,这是。
So it's nR integral from V1 to V2 dV over V.
即nR除以V乘以dV从V1到V2的积分。
p1 V1 Initial find -- there are many ways p2 V2 V1 I can get from one state to the other.
初态的氩气状态为,末态为。
V2 So, if one goes to two and V1 goes to V2, and it's constant temperature, just what we've specified there.
如果状态1变到状态1并且体积从V1到,同时温度保持不变,这就是我们这里要讨论的问题。
meke Argv2 So this is make Arg V2.
那么。
so we know how to do this, and we know this thing when it hit these stops, v2 the pressure with p2, and the volume was V2.
所以我们知道怎么计算,当活塞到达这两个挡板时,压强是p2,体积是。
p1V1/R That p2 V2 over R, and then I have p1 V1 over R, the R's cancel out.
就是p2V2/R除以,两个R消掉了。
Remember it's the external pressure that's important. In this case, because it's a reversible process, the external pressure turns out to be always the same as the internal pressure.
是过程非常缓慢,比如我把体积,从V1压缩到V2时,我做得十分缓慢,在过程中的任何一点。
v dv We have minus V1, V2, nRT over V dV.
负的v1,v2,nRT除以。
So now let's try looking at something V2 where are V1 goes to V2.
现在我们考察一个过程,这个过程中系统的体积从V1变到。
p1 An isobaric process followed by V2 a constant volume process.
先保持压强为,体积从V1压缩到。
V1 to the gamma is equal to p2 V2 to the gamma.
就是,p1,V1^γ,等于p2,V2^γ
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