Table 5-1 some representative values of us and uk Surface Rubber on dry 1.0 0.8 concrete Glass on glass 0.9~1.0 0.4 Steel on steel 0.6 0.6 Wood on wood 0.25~0.5 0.2 Waxed wood ski 0.04 0.004 on dry snowSurface Rubber on dry concrete 1.0 0.8 Glass on glass 0.9 ~ 1.0 0.4 Steel on steel 0.6 0.6 Wood on wood 0.25 ~ 0.5 0.2 Waxed wood ski on dry snow 0.04 0.004  s k Table 5-1 some representative values of and . k  s