Question

Air is enclosed by a rigid cylinder containing a piston. A pressure gage attached to the cylinder indicate an initial reading of 25Psi. Determine the reading Gage when the piston has compressed to air to one-third it's original volume assume the compression process to be isothermal and the local atmospheric pressure to be 14.7Psi

Answer 1

Isothermal  process :

$P_1\times V_1= P_2\times V_2$

where, $V_2=0.33 V_1$

$P_2=\frac{P_1V_1}{V_2} =\frac{25 \times V_1}{0.33\times V_1} = 75.76$ Psi