Three liters of saturated liquid R-134a at a constant pressure of 200 kPa is contained in an insulated piston-cylinder device. Inside the cylinder, an electric resistance heater is turned on and 900 kJ of energy is transferred to the steam. Determine the change of entropy of the refrigerant during this process in kJ/kgK (with three significant figures).

Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?