Physics Equation - Average Friction Force?

1/2 m v^2 = F x d

Friction is a force that is created whenever two surfaces move or try to move across each other.Friction always opposes the motion or attempted motion of one surface across another surface. Friction is dependant on the texture of both surfaces. Friction is also dependant on the amount of contact force pushing the two surfaces together (normal force). surface-on-surface hook velcro-on-fuzzy velcro >6.0 >5.9 avg tire-on-dry pavement 0.9 0.8 grooved tire-on-wet pavement 0.8 0.7 glass-on-glass 0.9 0.4 metal-on-metal (dry) 0.6 0.4 smooth tire-on-wet pavement 0.5 0.4 metal-on-metal (lubricated) 0.1 0.05 steel-on-ice 0.1 0.05 steel-on-Teflon 0.05 0.05