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The Physics Behind Skiing

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by

Lydia Hicks

on 11 October 2013

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Transcript of The Physics Behind Skiing

The Physics Behind Skiing
Contents
- Introduction: What is skiing?
- Forces Acting on a Skier
gravity, friction, centripetal and centrifugal forces, pressure
- Newton's Laws and Skiing
- Techniques for Managing Forces / Maximizing Speed

What is Skiing?
- Skiing is the action of traveling on top of snow on long blades, or skis, attached to your feet
- brief history of skiing
- Nordic vs. Alpine
- types of Alpine Skiing
Downhill Racing
Slalom Racing
Giant Slalom
Mogul Skiing
Freestyle Aerial Skiing


The Forces Acting on a Skier
-
Internal Forces
are forces generated by the skier through muscular-skeletal movements.
-
External Forces
are forces that act upon the skier. A skier must manage these forces through different types of movements to stay in balance:
-
Gravity
-
Friction
-
Centripetal Force
-
Centrifugal Force
-
Pressure
Techniques for Managing Forces / Maximizing Speed
- Skiers kick out/push off of the start gaits to begin their acceleration
- Skiers maximize their speed my minimizing their resistance to motion (drag force)
GS body suits
Aerodynamic boots, helmets, gloves etc.
Wax
Choosing the correct type of ski
- Reducing friction

By Lydia Hicks
Conclusion

- Learning to ski = learning to harness and manage the forces acting upon the skier
- As a skier develops skills and ability, they develop a desire to go faster on steeper terrain, which will result in the skier experiencing greater forces acting upon them
- The more we understand about the forces that are acting on us while skiing, the more able we will become to choose the right movements that will create successful outcomes... unlike these people...

Gravity
-
Center of Gravity
: the main location of the mass of a body, the theoretical point in the body where all mass acts as it it's concentrated
-
Base of Support
: the portion of the skis under the feet
- Gravity is the force that puts a skier into motion, and can be broken down into two components, G1 and G2
Friction
- A skier experiences two types of friction:
Friction from the surface of the snow
Friction from the air (wind/air resistance)
- Friction is what allows skiers to stay in control while skiing
- Friction during a straight run vs. friction in a hockey stop
- The amount of friction a skier will feel from the snow depends on the air temperature
- Skidding Turns vs. Carved Turns


Centripetal Force
- Centripetal force is the net force acting on an object when it's traveling in a circle
- Centripetal force is present in all turns
- To stay in balance, skiers must always move their center of gravity inside their base of support; this lateral movement is called
inclination
- The degree skiers can incline is defined by the amount of centripetal force acting on them
- Three types of turns:
Wedge (Snowplow)
Basic Parallel
Dynamic Medium Radius Turn
Centrifugal Force
- Centrifugal Force can be used to explain how a skier feels throughout a turn
- Centrifugal Force is only experienced and is not observed from outside the frame of reference
- If their ski was to disengage from the snow, the skier would not actually be thrown towards the outside of the turn
Pressure
- A skier standing still on two flat skis, with their center of gravity balanced over the middle of their base of support will be evenly balanced on two feet
- Pressure is represented by the equation
P=F/a
where P=pressure, F=force and a=area
- If the contact area is reduced or the force is increased, the pressure is increased
Newton's Laws
- First Law: objects in motion tend to stay in motion and objects at rest tend to stay at rest
- Second Law: F=ma
- Third Law: for every action there is an equal (in magnitude) and opposite (in direction) reaction
Example of a hockey stop
(1:20)
Types of Skis:
Racing Skis
Freestyle Skis
All Mountain
Full transcript