# Curling

## Physics within curling...

Curling is a winter Olympic sport that incorporates many physics concepts. Such concepts are shown as momentum exchange, kinetic energy, and frictional surfaces.
Friction is perhaps the most important aspect to this sport. A 42 pound rock is thrust down a lane of ice, and two team players sweep in front of the moving rock in hopes of reaching a designated area called the house. The team with the most rocks near the center of this area win. By sweeping in front of the rock, the players are reducing the amount of friction between the rock and the bumpy-surfaced ice. The sweepers use an abrasive material to genereate heat on the ice, which can produce a melted thin layer of water. This layer will create a path of minimal resistance for the rock to travel. You would think that a more flat and smooth surface would be ideal, when in fact, a flat and smooth surface can actually create more friction due to the forming of a vaccuum underneath the rock. This vaccuum will slow the rock down significantly. With a bumpy surface, there is less surface contact, therefore less friction.
Before all of the above occurs, the team member that starts off with rock in hand pushes off a hack while holding onto the rock outstretched in front of them. They apply force on the hack pushing themselves and the rock forward. This force transfers into the rock when released by the team member and heads on towards the sweepers.
The last aspect of curling is momentum. As a rock is nearing the house it is bound to collide with another rock. When is collides with another rock, the law of conservation of momentum is displayed.

M1V1 + M2V2 = M1V1 + M2V2

(Before Collision) (After Collision)

This formula expresses the law of conservation of momentum. Momentum is basically the mass of an object multiplied by its velocity. The formula means that momentum cannot be created nor destroyed, so that when two rocks collide the momentum is transferred from one rock to the other. The initial rock has a mass and velocity, which makes up its kinetic energy. This kinetic energy is trasnferred when the rock comes in contact with the other rock. This is the law of conservation of energy.