I know that friction is not really material based, instead is is system based (temp, preasure, etc. is effecting the result).
But to be honest I don't understand your last formula in relation to your first explanation. To explain what I mean I will use your example with Ice and a tire of rubber.
Ice has a very low friction, lets say 0.015.
the rubber tire has a very high friction of around 0.8 :
(Values are fantasy based).
normally you stated that the friction is much lower because of the ice friction. but with your last stated formula the friction always will be bigger than 0.8 . So the average value would be the most accurate in this case or did I understand you wrong?
But to be honest I don't understand your last formula in relation to your first explanation. To explain what I mean I will use your example with Ice and a tire of rubber.
Ice has a very low friction, lets say 0.015.
the rubber tire has a very high friction of around 0.8 :
(Values are fantasy based).
normally you stated that the friction is much lower because of the ice friction. but with your last stated formula the friction always will be bigger than 0.8 . So the average value would be the most accurate in this case or did I understand you wrong?