Question

Air contained within a vertical piston-cylinder assembly is shown in Figure 1.         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 valve is opened and air     enters the cylinder from the supply line, causing the volume of the air within the             cylinder to increase by 3.9 x 10^-4 m³. The force exerted by the spring as the air     expands within the cylinder varies linearly with x according to

F_spring = kx

            where k = 10,000 N/m. The piston face area is 7.8 x 10^-3 m². In common    application, with ignoring friction between the piston and the cylinder wall and             local acceleration of gravity is 9.81 m/s², pressure at initial position and final   position is 1.126 bar and 1.76 bar, respectively. Suddenly, the pressure at final      position was increase dramatic to 5.32 bar. As an engineer, you are ordered to           identify the main cause(s) and construct the corrective action to insure the             pressure at final position return to normal.  

Answer 1