Load weight in pounds - determine if any dead weights adds to the load (such as chain or belts).
steel on steel dry 0.8 - 0.5 greased 0.04 - 0.24
wood on steel dry 0.3 - 0.6  
wood on wood dry 0.3 - 0.5 greased 0.18 - 0.35
steel on polymer dry 0.2 - 0.45 greased 0.18 - 0.35
Angle of incline
  (+) positive angle is an incline
  (-) negative angle is a decline
Sliding Resistance Force
Variables   Units
W Load weight lb
μ Coefficient of sliding friction  
α Incline angle °
FL Resistance force load lb