Prob. # $4]$ A gas expands from an initial volume of $0\mathrm{.}028m^3$ to a final volume of $0\mathrm{.}17m^3$ in a constant pressure process at $650$ kPaa $.$ The initial and final internal energies are $42\mathrm{.}2$ kJ and $21\mathrm{.}1$ kJ $,$ respectively. Determine a$)$ the change in internal energy, and b$)$ the heat transfer. What does the sign of the heat transfer indicate?

Prob. # $5]$ A compressor compresses $0\mathrm{.}12\frac{m^3}{s}$ of air from an initial pressure $100$ kPaa to a final pressure of $620$ kPaa $.$ The initial density is $1\mathrm{.}27k\frac{g}{m^3}$ and the final density is $4\mathrm{.}92k\frac{g}{m^3}.$ Determine a$)$ the compressor discharge mass flow rate, and b$)$ the change of flow energy between boundaries.