A heat engine takes an ideal gas through a reversible cycle starting at 700 kPa and 2 m, through (1) an isothermal expansion to 7 m, then (2) an isochoric process that halves the pressure, then (3) an isobaric contraction, and finally (4) an adiabiatic expansion back to starting conditions. Draw a PV diagram for this engine. Indicate the values of pressure and volume that you can determine from simple proportional relations. For which process(es) is Q-0? W=0? AE int=0?