How Is Work Calculated in a Gas PV Diagram for Path a-d?

AI Thread Summary
The discussion focuses on calculating work done by a gas along different paths in a PV diagram, specifically path a-d. The user initially states that work can be calculated using W=P(delta)V for paths a-b and c-d, while noting that work is zero for paths a-c and b-d. The main question revolves around determining the work done along path a-d, where both pressure and volume change. It is highlighted that the area under the curve represents work, and since the path forms a trapezoid, integration is necessary to find the correct value. The conversation emphasizes the complexity of integrating pressure when it is not constant.
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Problem.
http://img294.imageshack.us/img294/8068/pvdiagram2fo.gif
Find Work done by each path.

My Solution.
a-b, c-d >> W=P(delta)V
a-c, b-d >> W=0

My Question.
What is the work done by the gas (path a-d)?

My Thoughts.
There is a change in both pressure and volume. However, the equation to find the work in this situation is "W=P(delta)V". There is no (delta)P.
 
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could anyone help him?I'm kinda interested in the answer to this as well!
 
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Are you familiar with integration? The answer is always found by calculating the area under the curve, which is exactly what you did for all the other ones. In this case, the area is a trapezoid
 
so the work done from a to d is W = deltaP * deltaV
very good, P is no longer constant so integrate that as well
as if it was that simple
 
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