# A piston and.. 9500 revolutions.. the system. Solved problem

#### A piston and cylinder machine containing a fluid system has a stirring device as shown in fig. The piston is frictionless, and it is held down against the fluid due to atmospheric pressure of 101.3 kPa. The stirring device is turned 9500 revolutions with an average torque against the fluid of 1.25 Nm. Meanwhile the piston of 0.65 m diameter moves out 0.6 m. Find the net work transfer for the system.

A piston and cylinder machine containing a fluid system has a stirring device as shown in fig. The piston is frictionless, and it is held down against the fluid due to atmospheric pressure of 101.3 kPa. The stirring device is turned 9500 revolutions with an average torque against the fluid of 1.25 Nm. Meanwhile the piston of 0.65 m diameter moves out 0.6 m. Find the net work transfer for the system.

1. Gas from a cylinder of compressed helium is used to inflate an inelastic flexible balloon, originally folded  completely flat, to a volume 0.6 m3. If the barometer reads 760 mm of Hg, what is the amount of work done upon the atmosphere by the balloon ? Sketch the system before and after the process.

2. Determine the work done by the air which enters into an evacuated vessel from atmosphere when the valve is opened. The atmospheric pressure is 1.013 bar and 1.5 m3 of air at atmospheric condition enters into the vessel.

3. A piston and cylinder machine containing a fluid system has a stirring device as shown in fig. The piston is frictionless, and it is held down against the fluid due to atmospheric pressure of 101.3 kPa. The stirring device is turned 9500 revolutions with an average torque against the fluid of 1.25 Nm. Meanwhile the piston of 0.65 m diameter moves out 0.6 m. Find the net work transfer for the system.