Recent content by doombanana

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    Amount of CO2 vaporized in a phase change from liquid to solid & vapor

    Homework Statement Saturated liquid CO2 is at T= 293 K and P=5.72*10^6 Pa and undergoes throttling to P=1.01*10^5. The resulting solid and vapor mixture is at T = 195 K. What fraction of the carbon dioxide is vaporized? (The enthalpy of the saturated liquid in the initial state is 24,200...
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    Lifetime of oil with exponential consumption rate

    We were told that the approximation does overestimate the lifetime by about 20 years. The equations I listed in the relevant equations section were given as hints as to how to solve the problem. By doing this he kind of explicitly walked us through the solution of the problem, but for some...
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    Lifetime of oil with exponential consumption rate

    Homework Statement The total amount of oil in a well is 24000 barrels. The present rate of consumption is 100 barrels per year. How long will the gas supply last if the present yearly rate of consumption increases by 1% per year? Homework Equations We can use the approximation (1+x)^i =...
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    Entropy change when converting water to steam

    Homework Statement At constant atmospheric pressure, 20g of water at 30C is converted into steam at 250C. Assume the heat capacity of liquid water is constant at 4.2 J/gK and the heat of vaporization at 100C is 2260 J/g. The molar heat capacity of water vapor at constant pressure is given by...
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    What is the Velocity of a Shank with Attached Spring Striking a Button?

    Ah, that's what it was. I forgot that the spring is compressed at the equilibrium point. Thank you again!
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    What is the Velocity of a Shank with Attached Spring Striking a Button?

    Homework Statement The shank of a 5-lb vertical plunger is .25 inches above a button when resting in equilibrium against the spring of stiffness k = 10 lb/in. The upper end of the spring is welded to the plunger, and the lower end is welded to the base plate. If the plunger is lifted 1.5...
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    Carnot Engine Between Reservoirs with Varying Temperatures

    Sign errors are the bane of my existence, but at least I see where it came from.:smile: Got it! Oooh, that is a bit of a shortcut and a more intuitive of setting up the problem. Thank you very much for your help! You've saved me hours of beating my head against the wall.
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    Carnot Engine Between Reservoirs with Varying Temperatures

    I guess finding this relationship is where I'm having trouble. Using Tsny's suggestion, from the first law I found that 1- \frac{|dQ_2|}{|dQ_1|}= 1-\frac{c_vdT_2}{-c_vdT_1}=1-\frac{T_2}{T_1} solving the last two parts of the equation for T2 gives T_2=\frac{T_1c_vdT_2}{-c_vdT_1} substituting...
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    Carnot Engine Between Reservoirs with Varying Temperatures

    Homework Statement Two containers with fixed volume are each filled with n moles of a monatomic ideal gas with constant heat capacity. Initially, the volumes of gas are at temperatures T_1,i and T_2,i. What is the maximum amount of work that can be obtained by operating an engine between the...
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