A model of the lungs can be made using a balloon inside a container fitted with a movable piston. The balloon is connected to the atmosphere using a pipe. Air is sucked into the balloon when the piston is lowered and expelled when the piston is raised. An idealized curve with straight lines instead of curves for sucking and expulsion is shown below. Note: The curve is labeled using gauge pressure rather than absolute pressure. Determine the net work done by the ballon in one cycle.