Internal energy and pv diagrams

AI Thread Summary
The discussion centers on calculating internal energy using the first law of thermodynamics, expressed as E = Q + W. The user has identified that for an isobaric process, the heat transfer Q is 200 J. They also mention using the work formula W = -PdV to find the change in volume. The calculated internal energy at this point is stated as U = 185 J. Overall, the user seeks confirmation on their approach and calculations regarding internal energy and PV diagrams.
coffeem
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[PLAIN]http://img689.imageshack.us/img689/511/pistonquerstion.jpg

This is my part attempt...

[PLAIN]http://img830.imageshack.us/img830/7342/internalenergyanswer.jpg

And ideas on how I can do the rest of it?
 
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Actuall I think I have managed to work outish a). I used the first law of thermodynamics: E = Q + W

then giving that in the question it says: Q(isobarbic)= 200j

So since W = -PdV = -P(Vf-Vi)

I for internal energy of the syster at this point: U = 185j

Am I doing it right?
 

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