How to Understand Skiboarding Physics

When you see a skiboarder apparently defying the laws of gravity, it's natural to ask how they do what they do. They seem to float through thin air and twirl like airborne tops and travel at fast-lane speeds down icy shutes, all with short boards attached to their feet. Impossible, you say? It's all in the physics. Here's how.

Instructions

Difficulty: Moderately Easy

1. Understand kinetic and potential energy. A skier at the top of a hill has a lot of potential energy because of being in an elevated position. That energy is spent, or becomes kinetic or active, as a skier moves down the slope. That's why as a skier goes downhill, he gains speed. Potential energy lessens and kinetic energy increases. At the end of the run, the potential energy is used up and kinetic energy diminishes rapidly.
2. Study friction. When a skier reaches the bottom of a slope and slows down because his potential energy is exhausted and his kinetic energy is lessening, it takes only a moderate amount of friction to bring movement to a halt. That friction, or resistance, is caused by the ski bottoms rubbing against the snow. Friction is necessary for skiing of any kind because such resistance helps in controlling speed, making turns and "carving" the ski edges into steep slopes.
3. Learn about acceleration and deceleration. Acceleration basically means the increase of speed or velocity over a period of time. Gaining speed is what helps boarders do their jumps and airborne tricks. And usually the time span for speeding up to a rapid pace is quite short. That's the fun of it! But it's also what can cause skiers to lose control and get injured. So, in deceleration, it's good to lose velocity in longer time spans. In other words, understand that it's better to glide to the bottom of the run than stop suddenly by hitting a tree.
4. Think about gravity. It's the force that keeps us anchored to the ground and prevents all manner of objects from floating around like they do aboard the Space Shuttle. Gravity is the pull exerted by the spinning of the earth. It's the most important physics law to understand with regard to skiboarding and skiing because without it, there would be no such sports! Without gravity, you wouldn't have potential or kinetic energy, friction or the ability to snow in powder or do aerial tricks.
5. Consider Newton's Law. One part says, "Bodies in motion will stay in motion and bodies at rest will stay at rest, unless moved by an external force." In skiboarding, this describes how friction from the snow (external force) causes a skier (body in motion) to slow down. Another part of Newton's Law helps explain why ski accidents can be so devastating (force = mass x acceleration). The force of a skiboarding impact is made greater by the size of the skier and how fast he is going.