A piston-cylinder device contains 1 kg of air at 100 kPa, 30oC. The gas is now compressed very slowly so that the temperature remains constant (isothermal). Calculate a series of states using the IG state daemon as the volume decreases from the initial value to one tenth of the initial volume. Draw a constant-pressure line through the calculated states on a p-v diagram. What kind of conic section (parabola, hyperbola, etc) does the p-v diagram resemble? How does the stored energy (E) of air changes as the volume decreases?