I always look forward to skiing in the winter. Now that I have taken physics, I can understand different concepts of physics involved in skiing. I'd say the most prevalent physics concept besides gravity is the force of friction on the skier's skis. Although the coefficient of friction is only .05 it creates a large impact on the skier. This matters a lot when you are a skier going off of jumps needing the perfect speed. When the snow is wet and sticky, it can be much harder to keep speed and the friction between the skis and the snow is stronger.
Another concept of physics in skiing is projectile motion when a skier is thrown off of a jump with great amounts of momentum. Skiers launch off of jumps in perfect parabolic paths with momentum due to their mass times their velocity. When a skier is in mid air or just skiing, there is a lot of air resistance that can effect the flight of a skier after launching off of a jump.
Some more talented trick skiers spin and do flips spinning every which way. It looks like they are defying gravity and going against all laws of physics but they are only timing their continuous spin. They can tweak the spin to turn different ways. All laws of physics still are applying, theses skiers are just good at looking smooth.