friction

[16adams]

Is there a difference in frictional coefficients for sliding verses rotation? I am working on a project where I going through someone else's work and his formula's use a rotational friction coefficient and a sliding friction coefficient. Does anyone have a reference name for me to look up the range of values?

Thanks

 

[braddles90]

What's the example? Is it like a wheel rolling/rotating down a plane vs. sliding down the plane? It sounds to me like he's referring to the coefficients for static friction (for the rolling/rotating case) vs. kinetic friction (for the sliding example). Most dynamics texts would have values for the sliding coefficient and statics texts should have statics values in them somewhere. Also try a google search for 'static' and 'kinetic' friction coefficients

 

[16adams]

This has to do with boring machine and the friction involved in the drill head and drill string. I agree that with your thought on his intent may have been static vs kinetic.

Thanks for your help.

 

[desertfox]

Hi 16adams

Have a look at this site below.
In general once there is relative movement between to surfaces sliding the coefficient of friction is reduced.

http://www.roymech.co.uk/Useful_Tables/Tribology/co_of_frict.htm

desertfox

 

[desertfox]

hi Again

Here is another site:-

http://hyperphysics.phy-astr.gsu.edu/hbase/frict2.html

desertfox