problem_in_recitation_2

# problem_in_recitation_2 - Solution to the problem in...

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Solution to the problem in recitation 2 KNOWN: Air in a piston-cylinder assembly undergoes a cycle of three processes. FIND: Work done in each process, net work and net heat. SCHEMATIC AND GIVEN DATA: ASSUMPTIONS: 1. Air is a closed system 2. Quasi-equilibrium processes 3. No change in KE and PE ANALYSIS: a) b) Before calculating work for any process, we must first find the pressure at state 2. 1 2 pV 1.4 = constant p 1 V 1 1.4 = p 2 V 2 1.4 p 1 = 101kPa V = 1m 3 p 2 = ? kPa V = 0.5m 3 p 3 = p 2 V = 1m 3 AIR IR AIR pV 1.4 =constant p = constant V = constant 1 101 0.5 1 ? 1 2 3 p (kPa) V (m 3 )

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1.4 1 2 1 2 V p p V = ( 29 1.4 3 2 3 1 101 0.5 m p kPa m = p 2 = 266.54 kPa For Process 1 2 2 1 12 V V W pdV = 2 1 12 1.4 constant V V V W dV = 2 2 1 1 12 1 p V pV W n - = - ( 29 ( 29 ( 29 ( 29 ( 29 ( 29 ( 29 ( 29 ( 29 3 3 3 12 2 3 266.54 0.5 101 1 10 1 1.4 10 kPa m kPa m N kJ W kPa m N m   -   = -     W 12 = -80.68 kJ (80.68kJ of work done on the gas) For Process 2 3 3 2 23 V V W pdV = Since p is constant in process 2 to 3, we can take p out of the integral 2 1 23 V V W p dV
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## This note was uploaded on 03/15/2010 for the course ENGRD 221 taught by Professor Staff during the Fall '08 term at Cornell.

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problem_in_recitation_2 - Solution to the problem in...

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