Recent content by rrushton

Got it Chet. Thank you so much for your time. And thank you nasu. I really appreciate it! What a great forum.

I understand there is a difference between static and kinetic friction. And that the former is higher than the latter. I don't understand Chet, because to my way of thinking, you can have a state of static friction between your finger tip and the back of your hand and still have different...

Thanks Chet. Wow, I'm going to have to think about this for a bit ... I'm pretty thick. So would you mind indulging me for a moment Chet. The two points I make in post #9, are they correct or incorrect. Sorry!

Thanks nasu. That's obvious to me now. The amount of shear that occurs within the skin will be related to both friction and normal force (therefore COF). But the shear modulus of the skin describes its ability to undergo shear. Thanks. So getting back to COF again. Every pair of materials has a...

I'm thinking of skin. If you press your fingertip into the back of your hand and wobble it back and forth (but keep it stuck to the same bit of skin), the amount of shear in the skin on the back of your hand depends on how hard you press and the friction level (put Vaseline on the back of your...

Thanks nasu - a ratio of two forces! So if the bottom surface is deformable (in both a perpendicular and horizontal direction) and it has an object on it, is it fair to say that the coefficient of friction describes the propensity for shear within that material?

I realize I've been thinking of friction and COF as the same thing - the degree of grip or slipperiness between two surfaces. Does this layman's definition reflect more friction or COF? What is a descriptive definition of COF? I'm really not good at physics, sorry!

I'm trying to get my head around the calculation for coefficient of friction: COF = Friction/Normal force. And what happens if you vary normal force. Am I right in saying: The COF is a constant - every pair of materials has a specific COF which is independent of how hard they are pressed...