TECHNIQUES

note:mind the language. Just see how beautiful ice skating is.These are examplesof spins in ice skating which called a bielman spin.

Techniques in ice skating
physics is applied in ice skating in order for skaters to perform their routine,maintain their balance and also in keeping their feet firm on the icy floor. 

1.       Friction

Friction occurs whenever we glide through an object or surface. In ice skating, friction is needed to start a stroke. As you angle your foot outward and extend the knee, the inside edge of the blade encounters the ice and the friction between the ice and the blade enables you to encounter resistance as you scrape the blade across the ice.ice skating is also about applying kinetic energy. As you exert the friction between the blade and the ice surface, the equal and opposite force within the icy edge propels resulting you to push forward across the ice. When it comes to stopping, instead of kinetic energy, you’re using pressure hence creating heat and sound.

2.      Torque

Torque is a rotational force or in Latin means “to twist”.  The definition of torque is the product of the distance from the axis of rotation with the force that is perpendicular to the lever arm. Torque is applied with the simple right hand rule. For example when opening a doorknob, That’s why doorknobs are located at the opposite side of the door to the hinges; it’s much easier to move the door out. In ice skating, in order to rotate, a skater  must exert a torque by pushing his or her body against the ice. In edge spins, the skater pushes one foot against the ice to start the turn.  Torque is also applied in multiple rotation edge jumps.

                                                           

                                                       

                                                   Figure 1:rotational force in skating.

3. Spin

Rotational Inertia

For straight-line motion, inertia is mass. For rotational motion, it's a bit more involved. It's harder to make a given mass rotate around an axis that it's far from than one that it's close to. The rotational inertia, or moment of inertia, I, of a single mass m rotating a distance r around an axis (like a planet around the Sun or a rock on a string) is given by

I = mr²

Note that rotational inertia increases as the square of the distance from the axis: if you double the distance of a mass from the axis of rotation, you quadruple the rotational inertia. This is why such a minor change such as a skater's leg position has such a huge effect on her rotational speed.

Rotational Speed

The other parameter of rotational motion is rotational speed, or angular velocity, . This is the rate of rotation, expressed in radians/sec, revolutions/minute (RPM) and other units. A complete rotation is 2 radians, so one revolution per second is an angular velocity of 2 rad/s.

Angular Momentum

Armed with rotational inertia and angular velocity, we can write the expression for angular momentum, L:

L = I

So, if angular momentum is conserved, and one factor like I changes, the other factor ( in this case) must change to compensate.