A gas is confined within a piston-cylinder device. The piston rests, stationary atop the gas and has a mass of 6.3 kg and a cross sectional area of 550 mm2. If atmospheric pressure is 104 kPa, determine the gage pressure of the gas in the cylinder and the absolute pressure of the gas in the cylinder.

The gauge pressure of gas is 112.5 KPa

The absolute pressure of gas is 216.5 KPa

Explanation:

Since, the piston is at rest. Hence, the gauge pressure of the gas will be equal to the pressure exerted by the weight of the cylinder.

Gauge Pressure of Gas = (Weight of Piston) / (Cross sectional are of piston)

Gauge Pressure of Gas = mg/Area

We have,

mass = m = 6.3 kg

g = 9.8 m/s²

Area = 550 mm² = 5.5 x 10^-4 m²

Gauge Pressure of Gas = (6.3 kg) (9.8 m/s²) / (5.5 x 10^-4 m²)

Gauge Pressure of Gas = 112.25 x 10^3 Pa = 112.5 KPa

Now, for absolute pressure:

Absolute Pressure of Gas = Gauge Pressure of Gas + Atmospheric Pressure

Absolute Pressure of Gas = 112.5 KPa + 104 KPa

Absolute Pressure of Gas = 216.5 KPa