Friction

For an object pulled or pushed horizontally, the normal force - N - is simply the weight: N = m g (2) where m = mass of the object (kg, slugs) g = acceleration of gravity (9.81 m/s2, 32 ft/s2) Frictional Coefficients for some Common
Materials and Materials Combinations Materials and Material Combinations Static Frictional
Coefficient - μs Clean and Dry Surfaces Lubricated and Greasy Surfaces Aluminum Aluminum 1.05 - 1.35 0.3 Aluminum- bronze Steel 0.45 Aluminum Mild Steel 0.61 Brake material Cast iron 0.4 Brake material Cast iron (wet) 0.2 Brass Steel 0.35 0.19 Brass Cast Iron 0.31) Brick Wood 0.6 Bronze Steel 0.16 Bronze Cast Iron 0.221) Bronze - sintered Steel 0.13 Cadmium Cadmium 0.5 0.05 Cadmium Chromium 0.41 0.34 Cadmium Mild Steel 0.461) Cast Iron Cast Iron 1.1, 0.151) 0.071) Cast Iron Oak 0.491) 0.0751 Cast iron Mild Steel 0.4, 0.231) 0.21, 0.1331) Carbon (hard) Carbon 0.16 0.12 - 0.14 Carbon Steel 0.14 0.11 - 0.14 Chromium Chromium 0.41 0.34 Copper- Lead alloy Steel 0.22 Copper Copper 1 0.08 Copper Cast Iron 1.05, 0.291) Copper Mild Steel 0.53, 0.361) 0.181) Diamond Diamond 0.1 0.05 - 0.1 Diamond Metal 0.1 -
0.15 0.1 Glass Glass 0.9 - 1.0, 0.41) 0.1 - 0.6, 0.09-0.121) Glass Metal 0.5 - 0.7 0.2 - 0.3 Glass Nickel 0.78 0.56 Graphite Steel 0.1 0.1 Graphite Graphite (in vacuum) 0.5 - 0.8 Graphite Graphite 0.1 0.1 Hemp rope Timber 0.5 Ice Wood 0.05 Iron Iron 1.0 0.15 - 0.20 Lead Cast Iron 0.431) Leather Oak 0.61, 0521 Leather Metal 0.4 0.2 Leather Wood 0.3 - 0.4 Leather Clean Metal 0.6 Leather fiber Cast iron 0.31 Leather fiber Aluminum 0.30 Magnesium Magnesium 0.6 0.08 Nickel Nickel 0.7 - 1.1, 0.531) 0.28, 0.121) Nickel Mild Steel 0.641) 0.1781) Nylon Nylon 0.15 - 0.25 Oak Oak (parallel grain) 0.62, 0.481) Oak Oak (cross grain) 0.54, 0.321 0.0721 Paper Cast Iron 0.20 Phosphor- bronze Steel 0.35 Platinum Platinum 1.2 0.25 Plexiglas Plexiglas 0.8 0.8 Plexiglas Steel 0.4-0.5 0.4 - 0.5 Polystyrene Polystyrene 0.5 0.5 Polystyrene Steel 0.3-0.35 0.3 -