[理工] [化熱]活塞彈簧組

看板Grad-ProbAsk作者kohtak ( )時間12年前 (2011/12/24 21:03)推噓2(2推 0噓 7→)

留言9則, 2人參與討論串1/2 (看更多)

Consider the cylinder filled with air and with the piston and spring arrangement shown below. The external atmosphere pressure is 1 bar, the initial temperature of the air is 25度C, the no-load length of the spring is 50 cm, the spring constant is 40000 N/m, the frictionless piston weighs 500kg, and the constant-volume heat capacity of air can be taken to be constant at 20.3J/mol‧K . Assume the air is ideal gas.Compute how much heat must be added to the gas in the cylinder for the spring to compress 2 cm? ──────── § ↑ 1 bar § 55 cm │ § │ │↓ § ↓│ ┌────┐←piston └────┘ │ │↑ │ │15 cm │ │ └────┘↓ Ans:Q=1026.5J W=-207.5J 想請問這題該如何算我在算出初始的壓力、莫耳數後，利用第一定律算出了內能變化量但卻苦於不知道如何算W 謝謝大家 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 203.67.161.40 ※ 編輯: kohtak 來自: 203.67.161.40 (12/24 21:12)

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