Re: [理工] [化熱]活塞彈簧組
※ 引述《kohtak ( )》之銘言：
: 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
利用邊界功的算法，壓力需考慮重力
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