The Physics of Skiing
With out kinetic(KE) and potential(PE) energy there would be no skiing. Here is how it works. You gain your potential energy when you either ride the ski lift or hike up. That is converted back into kinetic energy as gravity pulls you back down the hill, therefore KE=PE. That means that when you are moving up the hill you are raising the PE. You do this because you are working against gravity and the farther up the hill you go the farther that you can be pulled down the hill by gravity. Thus increasing your PE. That is all changed back into KE when you go down the hill. The equation for this is KE=PE=(1/2)mv^2. To find the total energy that you have you must add your KE and PE together.
Friction is what allows you to stay in control while skiing. It is what slows you down. You apply wax to the base of your skis to try and reduce this in order to go faster. In ski racing it is the person who allows the least amount of friction between themselves the snow and air that wins. In order to stop you use a lot of friction by appling your whole ski edge perpendicular to your direction of travel. With out friction we would not be able to experience the true joy of skiing. The equation for determining the coefficient of friction is µ=Fn/Ff. You can determine how much force the friction if creating by using the equation, Ff=µ(Fn). Ff equals the force created by the friction, and Fn equals the force perpendicular to the direction of travel.
In skiing acceleration and deceleration can be both fun and a killer. Your acceleration is what allows you to gain speed as you go down the hill. It is that speed you gain from your acceleration that allows you to do things like jump cliffs, table tops, etc. Deceleration is the biggest killer in skiing. The tree Sunny Bono hit caused a extremely rapid deceleration and the forces involved in that deceleration are what caused his fatal injuries. A quote I once read was, "Speed doesn't kill, deceleration however is another matter." In skiing your acceleration is caused by earths gravity. However you can experience acceleration and deceleration in many other things including driving your car. The basic defintion of acceleration is a change of velocity over a given time. The formula you would use to figure out you acceleration is acceleraton=(Velocity final-Velocity intial)/Time. To figure out your acceleration due to gravity during a cliff jump you would use the equation, Vfinal=Vinitial+(Gravity x Time). to find out the quantity for Gravity look below.
Without gravity there would be no skiing. Gravity is what pulls you down the hill. The absence of gravity negates both friction, and your kinetic and potential energy in skiing. If there was no gravity you would not be able to ski powder or jump cliffs like so many of the skiers and snowborders out there like to do. Gravity is the attraction that you have to the earth. On earth the force of gravity is 9.8 (m/s^2).
Newton's 1st law also plays a large role in the sport of skiing. This law states "An object in motion will stay in motion, and an object at rest will stay at rest until acted upon by an outside force." Therefore if there was no friction, and I pushed off of something I would continue monving indefinetly, but since friction is an outside force, it acts upon my skis and myself to cause me to stop. This is also part of what kills people. Sunny Bono would have kept going, except he encountered an outside force in the form of a tree. Newtons second law states that Force = mass x accleration (F=ma). This equation allows you to determine the amount of force you have due to your mass and acceleration. It also demonstrates that when you hit something while you are quickly accelerating skiing, you probably have quite a bit of force, and it is this force that actually hurts people. Newtons third law states that for every action there is and equal and opposite reaction. That means that when I ski down the slalom course and bash the gates each gate is exerting the same amount of force back on me that I am on it. The Reason that it bends and I don't is that I am considerably more massive than the gate. Thus the force has very little effect on my large mass, but a great effect on the gate's smaller mass.