The Physics of Skiing

Although my parents adamantly refused to let us ski (being that we've never done it before and have never taken lessons), we did visit one of the best skiing resorts in Quebec called Ville de Saint-Sauveur. We originally planned to go to Mont Tremblant, but decided against it because of Natasha Richardson's ski accident there in March. Nonetheless, I did take some pictures of the skiiers and as I watched them ski down the mountain, I was again reminded of Physics (this happened quite a lot in vacation--even then I couldn't stop thinking about Physics)!

Skiing involves a number of physics concepts that we've already learned including KE, PE, friction, momentum, and last but not least, Newton's Three Laws! As skiers hike up to the top of the mountain or ride the ski lift, their potential energy is increased because the farther up the hill they go, the higher value their height from the ground where PE=0 is going to be. When skiers speed down the mountain, PE is converted into KE.

Friction also plays an extremely important role in skiing especially in ski racing. Skiers apply wax on the bottom of their skis in order to reduce friction and therefore go faster. The skier who experiences the least friction between their skis / themselves and the snow & the air wins the race. Furthermore, friction also comes into play when skiers want to stop. In order to stop, skiers must apply the ski edges perpendicular to the direction they are traveling. Doing so increases the friction force as illustrated in the equation F = N(perpendicular force)u(mu).

Additionally, momentum is also a significant physics concept in that momentum makes skiing down long distances possible without tiring the skier. This is because momentum allows a skier to keep moving downward after pushing with his skis and / or poles (used to propel himself or herself forward). Thus, skiers can rest between each push because their momentum can carry them along.

Finally, Newton's 1st Law which states that an object in motion will continue to move in a straight line with constant speed unless acted upon by a net force also applies to skiing in that without the force of friction, the skier would continue moving but due to the application of friction on the skis and the skier, he or she can stop. Furthermore, Newton's 2nd Law (F=ma) also plays an important role in the sport's safety in that because skiers have a high acceleration as they speed down the slope of the mountain, the force of impact when they accidentally hit an object (like a tree or a boulder) is so huge that the force of impact is what hurts them. Newton's 3rd Law also applies in this scenario in that if an adult skier accelerating down a mountain collides with a stationary child down below, the skier exerts a force F on the kid and the kid exerts the same force F back on the skier. Logically, the child experiences a greater impact (more likely to be crushed by the F than the skier) because the child has a smaller mass than an adult skier.