I don't understand what you mean by additive value mean? 0.13 means thirteen one hundredths. That is the value of 0.13
Like stated earlier me, the final thumb rule would be extra mass extra friction. yet in precise phrases, F mN the place F is the friction rigidity performing on the field, m is Mu, the friction coefficient for the particular floor in question and N is the traditional rigidity performing on the field -- frequently, m*g*cos(attitude-of-slope).
