Using resistance while skiing: turning, traversing and initiating new turns

As you turn on skis, a few different things generally happen at once. Throughout the turn, you put more of your weight onto the outer ski. At this moment, the skis begin to turn sideways in a way which causes them to point directly across the slope at an angle. What all of this does is cause acceleration to start in a direction which moves directly across the slope. From this moment onwards, your body starts to move sideways along the slope without completely stopping. As you do this, you also simultaneously determine how much you need to tilt your skis onto their edges. The amount that you tilt your skis varies a bit depending on how much you want to accelerate (or decelerate). catskiing BC Canada

 

If we tilt the skis more, the larger resistance force we create also makes the sideways component of the reaction force larger and we will accelerate across the slope more. In the diagram the force up the slope is equal to the gravitational force down the slope, therefore all the resultant acceleration is sideways.

 

 

Traversing

 

At the end of a turn we generally ski across a slope with a constant velocity. To do this, we bring the skis more sideways to the slope, and angle them so that gravity is causing no accelerations or decelerations. Due to the effects of wind resistance and friction though we have to keep the skis pointing down the slope slightly do maintain a constant velocity. cat skiing BC Canada

 

 

Initiating a new turn

 

After skiing across the slope for a bit, we will want to make another turn, and to do this we need to create a sideways force across the slope in the other direction to the one we are traveling. By reducing our resistance to gravity we can let ourselves accelerate down the slope which will change our velocity down the slope, but we can't decrease our speed across the slope until we create a force pushing us across the slope in the other direction. To create this force we have to change the edges on our skis that are in the snow, as the edges we are on cannot push in the direction we need unless we angle the skis up the slope. To change the ski edges though we need to be traveling straight along the skis (this is explained further here in parallel turns). To do this we lean forwards to make the front of the skis fall into the fall line more, letting ourselves accelerate down the slope until the skis are pointing in the direction we are traveling. Coming through the fall line As soon as we are traveling along the skis we change the edges on the skis so that the other edges are in the snow. Notice that you will still be going across the slope when you have to change the edges on the skis, as your velocity across the slope will not change until you have changed the edges. Then as with turning across the slope in the first turn, by leaning on the outside ski we can bring the skis so they point at an angle to our velocity, and tilt the skis so that the edges create a sideways force across the slope. This creates acceleration back across the slope, and decreases our speed across the slope.