\sect{Baruch's B24.} A collection of free nucleons is enclosed in a box of volume ${V}$. The energy of a single nucleon of momentum ${\bf p}$ is $\epsilon_{{\bf p}} = p^{2}/2m + mc^{2}$ where ${mc^{2}=1000MeV}$. \begin{itemize} \item [(a)] Pretending that there is no conservation law for the number of nucleons, calculate the partition function at temperature ${T}$. (Nucleons are fermions). \item [(b)] Calculate the average energy density and average particle density. \item [(c)] In view of (a) and (b), discuss the necessety for a consevation law for the number of nucleons.\\ \end{itemize} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%