Aspring-loaded piston-cylinder device is filled with 0.35 kg of water vapor that is initially at 4 mpa and 4000c. initially, the spring exerts no force against the piston. the spring constant in the spring-force relationship is k = 0.75 and the piston diameter is d = 20 cm. the water now undergoes a process until its volume is one-half of the original volume. calculate the final temperature and the specific enthalpy of the water.