SnowBoard Acceleration

Pictures taken from Transworld Snowboarding Magazine Vol.16

The basic idea behind snowboarding is, of course, to be able to stand up and travel down the mountain without falling. The acceleration of a snowboarder primarily depends upon the slope of the mountain. However, in order to understand terms like acceleration and velocity, a person first must understand the importance of the coefficient of friction, which depends upon the amount of wax on the board, the more smoothly applied wax, the less the coefficient of friction will be, which means a greater velocity, and the type of snow- powder, wet snow, dry snow, icy snow. Overall, the kinetic coefficient of friction (Fk=Uk*n) varies from about .01 with a well waxed snowboard in icy conditions to .11 with a poorly waxed snowboard in wet snow. Therefore, the average kinetic coefficient of friction for a snowboard on the snow is approximately .06. The static coefficient of friction, Fs < or = Us*n , is the magnitude of the force of friction between any two stationary surfaces. Once the static force overcomes the static coefficient of friction multiplied by the normal force, the object will begin to move. For a snowboard on snow, the average coefficient of static friction is between .01 and .15 so it averages to be approximately .08.  When on a sloped part of the mountain, the downward force will be great enough to overcome the forces of static and kinetic friction and the boarder will travel downhill. To analyze the acceleration, a person must analyze both the horizontal and vertical forces. Using Newton's second law, F = m (mass) * a (acceleration), a person can analyze the snowboarder's acceleration. In the horizontal direction, Fx = m*Ax = m*g*sin(theta) where theta is the angle between the normal force and the combined weight of the snowboard and the snowboarder.  In the vertical direction, Fy = m*Ay = n-mg*cos(theta) where n is equal to the normal force exerted by the mountain against the board. Interestingly, these two masses cancel, and the acceleration, Ax=g*sin(theta) is constant and independent of the mass of the snowboarder. Therefore, a heavier snowboarder will not necessarily travel faster. However, a longer snowboard will travel slightly faster than a shorter one because it has a greater surface that is in contact with the mountain. To view some fast snowboarding with a twist, see the video at the bottom entitled “snowboard acceleration”.

Snowboard Acceleration

Movie Clip of Taylor Forman accelerating down a hill