Air contained within a vertical piston-cylinder assembly is shown in Fig.P1.43. On its top, the 10 kg piston is attached to a spring and exposed to an atmospheric pressure of 1 bar. Initially, the bottom of the piston is at x = 0, and the spring exerts a negligible force on the piston. The value is opened and air enters the cylinder from the supply line, causing the volume of the air within the cylinder to increase by 3.6 × 10-4 m3. The force exerted by the spring as the air expands within the cylinder varies linearly with x according to Fspring = kx Where k= 10,000 N/m. The piston area is 7.8 × 10-3 m2. Ignoring friction between the piston and the cylinder wall, determine the pressure of the air within cylinder, in bar, when the piston is in its initial position. Repeat when the piston is in its final position. The local acceleration of gravity is 9.81 m/s2.

Air supply line x=0 Valve Air