A piston-cylinder assembly fitted with a spring. The cylinder contains water, initially at 538oC, and the spring is in a vacuum. The piston  face, which has an area of 125 cm2 , is initially at x1=50 cm. The water is cooled until the piston face is at x2=40 cm.
The force exerted by the spring varies linearly with x according to F=kx where k=350 N/cm. Friction between the piston and the cylinder is neglible. For the water determine
a. The initial and final pressures, and the amount of water present
b. Work and heat transfer