An insulated, vertical piston-cylinder assembly (see figure) contains 50 L of steam at 105oC. The outside pressure is 101 kPa. The piston has a diameter of 20 cm and the combined mass of the piston and the load is 75 kg. The electrical heater and the paddle wheel are turned on and the piston rises slowly by 25 cm. Determine
(a) The pressure of air inside the cylinder during the process
(b) The boundary work performed by the gas
(c) The combined work transfer by the shaft and electricity if the net energy transfer into the cylinder is 3.109 kJ.