text: ,L= F/N 
  
  where 
  
  p =coefFicient of friction (mu) 
  F =friction 
  force, Ibs. 
  N = normal force, lbs. 
  
  The coefficient of friction of tires on a runway 
  surface is a function of many factors. Runway 
  tread, 
  surface condition, rubber composition, 
  shearing 
  inflation pressure, surface friction 
  stress, relative slip speed, etc., all are factors 
  which affect the coefficient of friction. When 
  the tire is rolling along the runway without 
  the use of brakes, the friction force resulting is 
  resistance. The coefficient of 
  simple rolling 