Physics of Snowboarding
The physics of snowboarding involves the forces acting to produce the downward movement of the rider and the forces that influence the rider’s balance and maneuverability.
The forces affecting downward acceleration are generated by gravity providing the “pull” while friction and air resistance act to reduce the influence of the gravitational force. Therefore the primary focus of the sport will be to minimize the effect of these forces to maximize the speed obtained from gravitational work.
If we imagine an idealized snowboard ride which takes place on a frictionless surface and is completely vertical, then this would behave exactly the same as free fall through the air. As the angle of downward motion is reduced, the maximum acceleration provided by gravity is correspondingly reduced until we reach a completely flat surface where it ceases completely. Therefore the maximum speed attainable by the snowboarder will be initially influenced by the angle of the surface during descent.
However, the forces of friction and air resistance will act to further reduce the attainable velocity, so any factors which can reduce these influences will affect the ride. One of the first elements that reduces the friction of the board is the water lubricating the snowboard on the snow. A small of water is created when the friction of the snowboard generates a sufficient amount of heat to melt the snow it is in contact with. This thin later of water acts as a buffer between the snowboard and the snow itself which causes an effect similar to “hydroplaning” which minimizes the frictional contact between the two surfaces. This will also cause the snow surface to become more firm which allows a faster descent. Fresh powdered snow lacks sufficient density to be a good surface and will contribute too much friction to attain high velocities.
An additional factor which is directly related to the surface friction is the design of the board itself. Racing boards with a lighter, sleeker design will be faster than free-style boards, since with less surface contact the effects of friction are reduced.
Air resistance against the rider can be minimized by using aerodynamically favorable stances and equipment. This will reduce the drag on the rider by ensuring an airflow that minimizes the turbulence associated with speeds.
Additional forces are involved in maneuvering the board which involves the interaction of the rider with the board. Shifting the weight causes changes in direction which can be used to reduce the acceleration and allows the rider to maintained control to avoid going into a “freefall” type of ride. The act of shifting weight causes the board to reduce contact with the snow surface on one side while increasing it on the other. This contact differential will cause the board to change direction towards the source of the least resistance. During turns, a higher tilt of the board reduces the turning radius which is also due to the reduced surface contact of the board. In order to maintain control, the rider’s center of gravity must remain perpendicular to the edge of the board maintaining surface contact to provide stability. This results in the center of gravity always being kept in a straight line with the surface of the board. It is easy to observe that even extreme turns are performed while the center of gravity is aligned in a straight line with the board’s surface.
In conclusion, while gravity is the determining factor in the maximum attainable velocity, factors that can reduce frictional influences and air resistance will allow the rider to get as close to this value as possible. From this maximum velocity, the rider must maintain a sufficiently high level of control to retain the ability to maneuver and direct the board for the ride.