coeff of friction

Coefficients of friction of common surfaces
摩擦係數表

surface condition ____ mu_s __ mu_k __ %diff
----------------------------------------------
dry glass on glass ___ 0.94 __ 0.40 __ 54%
dry iron on iron _____ 1.10 __ 0.15 __ 86%
dry rubber on pavement 0.55 __ 0.40 __ 27%
dry steel on steel ___ 0.78 __ 0.42 __ 46%
dry teflon on teflon _ 0.04 __ 0.04 __ ---
dry wood on wood _____ 0.38 __ 0.20 __ 47%
ice on ice ___________ 0.10 __ 0.03 __ 70%
oiled steel on steel _ 0.10 __ 0.08 __ 20%

source: DM Bourg, Physics of game developers. (Sebastopol: O'Reilly, 2002)