Re: What are the physics theories involved in ski jumping?

Ski jumping sure looks like a fun sport and can be studied using 
conservation of energy and a little aerodynamics.  At any given time the 
skier's energy is the sum of potential energy and kinetic energy. Let's 
ignore friction and air resistance for now, so that the energy equation is 
easy.  The key point then is that ENERGY IS CONSERVED.

Putting this into an equation:

Energy = mass * g * height + 0.5 * mass * speed ^2.

At the starting point some 80 meters up the slope, the energy is all 
potential because the skier is not moving.  

At the point of take off (the end of the ramp) the skier has gained kinetic 
energy equal to the loss in potential energy (again ignoring friction).

Once the skier is airborne he is a projectile subject to gravity and the 
forces that come from moving through the air.  The skier is can be thought 
of as an airplane wing or an airfoil.  To get maximum distance, the skier 
must maximize lift and lower drag.  Spreading the skis into a "V" gives the 
skier more surface area and increases lift.  Crossing the skis to a point (V) 
helps reduce drag because objects with pointed tails have less drag than 
objects with blunt tails.

The designers of the jump sight try to shape the hill like a parabola that 
matches the general path of a projectile launched from the ramp just like 
the ski jumpers.  The shape of the hill is a safety feature: the skier is 
never more than about 3 to 5 meters off the ground.    

I will defer a more detailed calculation to ski jump simulations and 
experts in the field.

some reference on ski-jumping with a few cool pictures can be found at:


www.wintersports.org/skijump/description/index.html


cbs.sportsline.com/u/olympics/nagano98/ski_jumping/index.html 


www.cdnsport.ca/jump/html/scoring.html 


www.cdnsport.ca/jump/html/media.html 


Sincerely,
Tom "Flying Loon" Cull