[題目] 推甄題目2題

看板Physics作者 (小黃)時間14年前 (2011/10/08 14:08), 編輯推噓2(3推 1噓 5→)
留言9則, 8人參與, 最新討論串1/1
[領域] 熱力學 與 力學 (題目相關領域) [來源] 碩士推甄試題 (課本習題、考古題、參考書...) [題目] 1. The gravitational force between two particles with masses m and M , initially at rest at great seperation , pulls them together . Show that at any instant the speed of either particle relative to the other , d is their separation at that instant . 2. You have 1 mole of helium gas and 2 mole of neon gas in two containers with same temperature and pressure . After you mix them together with the same fixed temperature and pressure , the increase of the system entropy is _____ R , where R stands for the universal gas constant . [瓶頸] (寫寫自己的想法，方便大家為你解答) 0.5 0.5 1. 我相對速度是把兩個的速度相加，算出[G(M+m)/d] ，但是答案是[2G(M+m)/d] 不知道哪邊觀念錯了... 2. 混合後的壓力、溫度同，體積不是也相同?? 看不太懂題目的意思 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 1.175.129.130
→
10/08 14:49, , 1F
1.能量: 0=-GMm/d +(p^2)/2M+(p^2)/2m; 動量 p=mv=MV;A: v+V
10/08 14:49, 1F
推
10/08 18:22, , 2F
能量: 0=-GMm/d +0.5μVr^2 .. Vr = [2G(M+m)/d]^0.5
10/08 18:22, 2F
→
10/08 23:35, , 3F
112?
10/08 23:35, 3F
推
10/09 21:51, , 4F
第二題 ds= [n*R*ln(V2/V1)]= [1*ln(3)+2*ln(3/2)]*R
10/09 21:51, 4F
噓
10/11 09:34, , 5F
第一題的英文好爛, 不知道在問啥.
10/11 09:34, 5F
→
10/11 12:36, , 6F
哈. 第一題英文的確亂七八糟
10/11 12:36, 6F
→
10/14 08:57, , 7F
用不著噓吧....題目就是這樣寫= =
10/14 08:57, 7F
→
10/15 23:52, , 8F
抱歉, 那個噓想噓的是題目本身, 不是 po 版的人.
10/15 23:52, 8F
推
10/15 23:53, , 9F
幫推回來
10/15 23:53, 9F
‣ 更多 gary85238 的文章
文章代碼(AID): #1EZ-ZIoF (Physics)