A standard Diesel cycle engine operating with air has a cut off ratio of $2\mathrm{.}5$ and compression ratio of $16.$ The working fluid is at $100$ kPa and $25$C at the beginning of the compression step $($point $1).$ Assume air is an ideal gas with Cp$=(7/2)$R$,$ Cv$=(5/2)$R$.$ Calculate the following:

a$.$ Wnet of the cycle $($J$/$mol$)$

b$.$ Mean effective pressure $($KPa$)$

c$.$ Thermal efficiency $(\%)$