# Physics of Ice Hockey

Physics of Ice-Hockey

The velocity and force with which a puck can be shot in an ice-hockey game can get a little bit scary.  Most professionals who understand the physics behind taking a powerful slap shot are capable of putting the puck on net at velocities of well over 100mph.  To properly take a slap shot, a player must first lift his stick up over his shoulder, cock it back, and strike the ice just behind the puck.  Different brands of sticks have various levels of flex capabilities that allow players to bend their sticks to different extents.  When a player flexes, or bends, his stick, energy is stored in the blade.  As a player makes contact with the puck during a slap shot, he shifts his weight and flicks his wrists.  This rotation causes the stored energy to release off of his stick and transfer to the puck. Once the puck is struck, the amount of kinetic energy that has been supplied onto it is equal to the amount of energy stored in the stick.

Energy goes from player to stick, then from stick to puck.

The physics of skating are also very interesting.  Professionals are capable of skating both frontwards and backwards at speeds far faster than a human would be capable of running.  This is because of the capabilities players have to gain speed quickly by digging the edges of their skates into the ice and pushing off.  The low friction of a skate’s blade is what allows a hockey player to glide all over the ice’s surface while making it appear to be an effortless motion. (1)  The width of the skate’s blade is about 3 mm.  The skate’s design allows for the skate to successfully glide over irregularities in the ice. (2)  We see Newton’s third law, which suggests that whenever one object exerts a force on a second object, the second exerts an equal and opposite force on the first.  This explains why players must push their skates backwards in order for the ice to push them forward.

2)   http://www.hockeyphysics.com/icehockey.html