4. (15 pts) Initially, 1.361 kg of steam is contained in a piston-cylinder device at 260°C with a quality of0.7. Heat is added at constant pressure to allow for expansion while all of the liquid is vaporized. The steam then expands adiabatically at constant temperature to a pressure of 2758 kPa, behaving essentially as an ideal gas. Determine the work done BY the steam ON the piston. Determine the work done BY the piston ON the atmosphere. What is the useful amount of mechanical work produced in this process?

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