Name:

A#

Problem $3$: $(8$ pionts$)(40$ mins $)$

A cylinder fitted with a piston and a linear spring initially contains saturated water vapor at $200$kPa $($state $1).$ Under these conditions the piston is $Z_1=909mm$ from the left end of the cylinder. The crosssectional area of the cylinder is $0\mathrm{.}05m^2.$ The spring force is given by $Fs=kz$

where the spring constant is given as $k=11k\frac{N}{m}$ and $z$ is the distance in mm between the piston face and the left end of the cylinder. The contents of the cylinder are then cooled until the pressure reaches $100$ kPa $($state $2).$ Assume that pressure changes in a linear manner between state $1$ and state $2$ and that the surrounding air temperature is $20C.$

a$)$ draw and label a $T-s$ diagram, relative to the vapor dome

b$)$ determine the amount of heat transferred $[$kJ$]$

c$)$ determine the entropy produced during the process $k\frac{J}{K}$

Solution