In skiing, to go really fast you want to have your skis waxed. This is because having your skis waxed decreases the coefficient of friction which decreases the frictional force that is working against you. The equation for frictional force is Ff=(coefficient of friction)(normal force). The coefficient of friction of waxed skis on snow is .05. This number is unitless. The normal force is your mass x gravity which my mass is about 77kg and gravity is always a constant on earth, 9.81 m/s^2. Here is how the equation looks now Ff=(.05)(77kg x 9.81m/s^2). The total frictional force comes out to be around 37.77 Newtons. This all depends on the coefficient of friction and your mass.