The Physics of a LAX Goalie

The Physics of a LAX Goalie

Jules R. Gonsoulin

You wouldn't guess it at first, but the goalie actually controls the speed and flow of a lacrosse game.  He is the "defensive quarterback".  He needs to know how to make good outlet passes.  Outlet passes are made after a save and are used to send the ball back down the field.  In order for an outlet pass to be successful, it needs to have height and speed.  That is where PHYSICS come into play.

The most important concept to understand is that the height of a projectile controls the amount of time it is in the air.  This is due to the equation, d = 1/2 g t^2.  The longer an object is in the air, the farther it will go.  Thus, you want to release the ball when it is at its highest point, so it will stay in the air for a long time, and you can complete long, full-field passes.

Tangential speed also comes into play here.  The farther away an object is from its center of rotation, the faster it will have to move to keep up with the center.  Since the stick is a rotating body, the objects farthest from the center of rotation will have the most horizontal velocity when released.  Since the ball is the farthest object from the center, it will move very quickly out of the stick.  If you can get the ball to move faster, your passes will be completed quicker, and your clears will be more efficient.

Principles Represented:

• Torque
• Rotational Motion
• Tangential Speed
• Projectile Motion

IDENTIFICATION- This photo is natural.