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Cyclic proces, confused

  • Thread starter lesodk
  • Start date
  • #1
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1. Homework Statement

A Cyclic proces of three parts for a monoatomic idealgas:

1-2:
Isochor, where:
p2 = 2*p1
v2 = v1

2-3:
Adiabatic, from v2 = v3, where:
v3 > v2
p3 = p1

3-1:
unknow proces, where
v4 = v1
p4 = p1

My problem is to determine
Q1, Q2, Q3 and W1, W2, W3 and dU1, dU2, dU3

I can't find U3, W3

2. Homework Equations
dU1 + dU2 + dU3 = 0

W1 = 0, dU = Q (isochor)
Q2 = 0, dU = -W (adiabatic)

3. The Attempt at a Solution
I'm really lost on the part finding Q3, W3
:(
 

Answers and Replies

  • #2
Hootenanny
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Have you determined dU1 and dU2?
 
  • #3
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yes i have
 
  • #4
Hootenanny
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And is the data plotted on a PV curve?
 
  • #5
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Nope, i don't have that information.
 
  • #6
Hootenanny
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A Cyclic proces of three parts for a monoatomic idealgas:

1-2:
Isochor, where:
p2 = 2*p1
v2 = v1

2-3:
Adiabatic, from v2 = v3, where:
v3 > v2
p3 = p1

3-1:
unknow proces, where
v4 = v1
p4 = p1
Shouldn't these two values be v3 and p3?
 
  • #7
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my point is just that after v3 and p3, you go back to the initial place v1 and p1.
Thats what i mean by 3-1.
 
  • #8
Hootenanny
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my point is just that after v3 and p3, you go back to the initial place v1 and p1.
Thats what i mean by 3-1.
Yes but note that p3 = p1, therefore this third 'unknown process' (3-1) is isobaric.
 

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