## Coaching Corner

Coaching Corner is our resource to help you enjoy and be succesfull at Short Track Speed Skating. It will your guide on everything from the basic equipment needed, how to look after you equipment; how to sharpen blades right through to skating technique and training programmes. Click on the links below for more info: -

How to Sharpen Your Skates

info to appear here incuding "How to" guides and lots of other information to be a good speed skater....it will be your guide to Short Track Speed Skating Equipment (Race suits; Boot; Blades; Offsets; Sharpening; Types of Helmets....etc); it will help you understand how to and what equipment you need to sharpening blades;

- How to sharpen blades

- How to train for Short Track

- and lots more will be here.....

## Geeks Corner

The Physics of Short Track (www.real-world-physics-problems.com)

Where:

g is the acceleration due to gravity, which is equal to 9.8 m/s2 on earth

G is the center of mass of the system (which consists of skater plus skates, which together can be treated as a rigid body)

P is the approximate contact point between the skater's blades and the ice

L is the distance between point P and point G

Fx is the horizontal contact force, with the ice, acting on the skater's blade at point P

Fy is the vertical contact force, with the ice, acting on the skater's blade at point P

R is the radius of the turn, measured from the center of the turn to the center of mass G of the system

ac is the centripetal acceleration of point G. This acceleration is in the horizontal direction and points towards the center of the turn

θ is the angle between the horizontal and the line passing through points Pand G. This is the angle of "lean" (a constant)

The center of mass G has zero vertical acceleration. Therefore, the forces in the vertical direction acting on the system must sum to zero. Mathematically this can be written as

where m is the mass of the system (which consists of skater plus skates).

Apply Newton's second law in the horizontal direction:

The centripetal acceleration is given by

where v is the velocity of the center of mass G. This velocity is pointing out of the page.

Substitute this equation into the previous equation and we get

Since θ is constant, the system is in a state of rotational equilibrium. This means there is zero moment acting on the system about the center of mass G, about an axis pointing out of the page. Mathematically we can write this as

(Note that we are ignoring three-dimensional effects in this equation. They are assumed to be negligible).

Combine equations (1)-(3). We get

Based on this result we can do a sample calculation. For example, let's say R = 8.5 m and v = 10 m/s. The angle of lean is θ = 39.8° .