Dynamic Friction Coefficient
Kinetic (or dynamic) friction occurs when two objects are moving relative to each other and rub together (like a sled on the ground).
Applicable units are those of quantitykind:FrictionCoefficient
http://en.wikipedia.org/wiki/Friction
http://dbpedia.org/resource/Friction
Kinetic (or dynamic) friction occurs when two objects are moving relative to each other and rub together (like a sled on the ground).
$\mu = \frac{F}{N}$, where $F$ is the tangential component of the contact force and $N$ is the normal component of the contact force between two sliding bodies.
http://www.iso.org/iso/catalogue_detail?csnumber=31889