Vector Dynamics Application

Vector dynamics can be applied everywhere we look. Although we learned more about vector dynamics, a large part of this unit was focussing on inclined planes, therefore, a practical application of vector dynamics is skiing. Skiing has always been a sport that I have wanted to do more often. I have had the opportunity to ski on local mountains and have loved the few time I have been able to go! There are many different types of skiing, and all would show good examples of how forces act on an object, whether the person is skiing down a hill, or on a flat surface like cross country skiing.

https://www.inkling.com/read/college-physics-openstax-college-1st/chapter-5/example-5-1

In this diagram, we can see that the skier is on a incline of 25 degrees, and the free-body diagram shows that there is a normal force, (Fn) the force of friction (Ff), and the force of gravity (Fg) acting on the skier. The force of friction would come from the snow under skis. As we have learned in this unit, the force of gravity can be split into 2 components, a parallel component, and a perpendicular component. We separate gravity into components so that the perpendicular component balance Fn, and the parallel component is parallel to the direction the object is moving in, and the force of friction. 

We have already learned that we can find Fg perpendicular by using the formula, mg cos θ. In this situation, θ is 25 degrees because the incline of the surface is 25 degrees. Additionally, Fg parallel= mg sin θ. With these components, we could now find values such as the force of friction, and the acceleration of the skier, depending on the other information given. This type of information can be especially useful if you practice ski jumping, which can be based on how fast you accelerate down the hill, and how far you can jump. 

http://www.saugeentimes.com/Pictures/Misc%20Clip%20Art/Cross%20Country%20Skier.jpg

For a cross country skier, who must move on a relatively flat terrain, the forces acting on them are the normal force (Fn) the force of gravity (Fg), and the force of friction, however friction plays a more prominent role in cross country skiing. If you have looked at cross country skis, you will notice that the skis will not lie completely flat against the snow. This is because a cross country skier, needs both high and low friction forces while skiing. Friction needs to be low when the skier is gliding forward, however it needs to be high when you kick back and grip the snow to move. This arch in the ski allows you to adjust your weight depending on the situation. When you guide the ski forward or are going downhill, your weight on the skis decreases, and the arch ensures that the middle portion of your skis do not make contact with snow, therefore, there is less friction. However when you kick back, your body weight pushes on the ski, and the middle section touches the snow, therefore more friction!

http://sciencenordic.com/physics-cross-country-skiing