As fall lacrosse is starting to end (last tournament this Saturday), I decided to think about the physics behind the sport I love. 

The first thing that comes to mind that involves a variety of physics factors in lacrosse is the shot. One of the most important factors in a successful lacrosse shot is the legs. First of all, since the body is rotating extremely fast during a lacrosse shot, in order to aim successfully, you have to keep your feet pointed towards the target in order to release the ball at the correct location. Also, in a "time and room" lacrosse shot, the wind up of taking a crow-hop (like baseball throws) or a back-step creates linear momentum so when you plant your front foot and start rotating your torso, the linear momentum is converted to angular momentum to help your upper body rotate faster. While shooting on the run, you cannot plant your foot, but it is important to turn your torso away from the goal in the wind up to get the angular momentum necessary for a fast shot. Another factor allowing a lacrosse shot to be 80-90 mph in high school (100-110 in pros) is that Torque is the product of Force and the length of the lever arm and the lacrosse stick acts as a long lever arm. It is important to extend your arms back as far as possible as well while winding up because that helps increase the length of the lever arm even more. When it is time to actually shoot the ball, the head of the lacrosse stick goes from behind your head, around your shoulder, and pointed towards your target in a fraction of a second, allowing a goalie to have less than half of a second to react. There is so much torque and whip generated during a successful lacrosse shot that during the shot, you can usually hear the air resistance against the lacrosse stick, making a "whoosh" sound. 

Hopefully, knowing the physics behind the shot will help me score a lot of goals this year. 

Photo is of Paul Rabil generating as much torque as possible on a shot on the run.