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Unformatted text preview: Spring 2006 1 ME 201 Thermodynamics Homework #4 Solutions 1. (3 pts)Assuming an ideal gas calculate the specific volume in the appropriate units for: a. N 2 at 500 kPa and 900 K b. Neon at 1 psia and 500 R c. Air at 14.7 psia and 72 ° F Solution: We will use v = R T MW P u ⋅ with the molecular weight coming from Table A1 or Table A1E. a. MW = 28.013 R u = 8.314 kPa ⋅ m 3 /(kgmole ⋅ K) v = (8.314)(900)/[(28.013)(500)] = 0.534 m 3 /kg b. MW = 20.183 R u = 10.73 psia ⋅ ft 3 /(lb m mole ⋅ R) v = (10.73)(500)/[(20.183)(1)] = 265.82 ft 3 /lb m c. MW = 28.97 R u = 10.73 psia ⋅ ft 3 /(lb m mole ⋅ R) v = (10.73)(460+72)/[(28.97)(14.7)] = 13.40 ft 3 /lb m 2. (5 pts) Calculate the specific internal energy change for H 2 by assuming a temperature variation in c v (i.e., integrating) at 700 kPa as its temperature changes from 350 K to 1300 K. Solution: Recall from class that we have Δ u = c dT v T T 1 2 & but [ ] ( ) [ ] c = c R = 1 MW a + bT + cT + dT R = 1 MW a  R + bT + cT + dT v P 2 3 u 2 3 ME 201 Thermodynamics...
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This note was uploaded on 07/25/2008 for the course ME 201 taught by Professor Somerton during the Spring '06 term at Michigan State University.
 Spring '06
 SOMERTON

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