Work (continued)

Diagram p x V

It is possible to represent the isobaric transformation of a gas through a diagram volume pressure:

Comparing the diagram to the expression of the calculation of the work done by a gas , it is possible to verify that the work performed is numerically equal to the area under the graph curve (in blue in the figure).

With this verification it is possible to find the work done by a gas with variable pressure during its transformation, which is calculated using this conclusion, through an academic level method of integral calculation, which consists of an approximation dividing the whole area under the graph into small rectangles and trapezoids.