piston

[logistic_guy]

The piston of a vertical piston-cylinder device containing a gas has a mass of \(\displaystyle 40 \ \text{kg}\) and a cross-sectional area of \(\displaystyle 0.012 \ \text{m}^2\). The local atmospheric pressure is \(\displaystyle 95 \ \text{kPa}\), and the gravitational acceleration is \(\displaystyle 9.81 \ \text{m/}\text{s}^2\). \(\displaystyle \bold{(a)}\) Determine the pressure inside the cylinder. \(\displaystyle \bold{(b)}\) If some heat is transferred to the gas and its volume is doubled, do you expect the pressure inside the cylinder to change?

 

[logistic_guy]

Determine the pressure inside the cylinder.

\(\displaystyle P = P_g + P_a = \frac{F}{A} + 95000 = \frac{40 \times 9.81}{0.012} + 95000 = \textcolor{blue}{127700 \ \text{N/}\text{m}^2}\)

 

[logistic_guy]

\(\displaystyle \bold{(b)}\) If some heat is transferred to the gas and its volume is doubled, do you expect the pressure inside the cylinder to change?

No, I expect the pressure inside the cylinder to remain constant as neither the pressure from the piston’s weight nor the atmospheric pressure has changed.