The following data was obtained from a constant pressure cake filtration experiment:

$\backslash$table$[[$Time $(s),5,10,20,30],[V(t)($litres$),0\mathrm{.}040,0\mathrm{.}055,0\mathrm{.}080,0\mathrm{.}095]]$

The following additional information is given: $A=0\mathrm{.}1f{t}^2,C_s=0\mathrm{.}015k\frac{g}{l},=1\mathrm{.}1$ centipoise, $P=10\frac{N}{m^2}.$

a$)$ Determine $R_M$

b$)$ Determine the specific cake resistance