The Physics of Lacrosse

Recently, while filming a project for science class, I enlisted the help of my father. A former All-American high school defenseman and highly dedicated college player, Bernie Echavarri was very useful. My project was on the physics of different sports, and it was for the sport lacrosse in which I recruited the assistance of my father.

For the lacrosse portion of my project I connected the sport to Newton's three laws of motion. You can see below, in the table, how each law connects to the sport lacrosse. 

Newton's First Law: "An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force." (http://www.physicsclassroom.com/class/newtlaws/Lesson-1/Newton-s-First-Law)
Newton's Second Law: "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." (http://www.physicsclassroom.com/class/newtlaws/Lesson-3/Newton-s-Second-Law) Simple version: Force x Mass = Acceleration
Newton's Third Law: "For every action, there is an equal and opposite reaction." (http://www.physicsclassroom.com/class/newtlaws/Lesson-4/Newton-s-Third-Law)

Newton’s First Law     Newton’s Second Law         Newton’s Third Law

When a passing or shooting, the ball continues to move in a straight path until acted upon by another player’s stick or by the back of the goal. Gravity is a big part in this system; gravity will gradually bring the ball back down to the ground if a player doesn’t get a chance to catch the pass. Or if the pass is off, or if it just doesn’t make it to the player. Whatever the circumstance, the ball will come down. If a ball is at rest in a player’s stick until the player starts to cradle, when the player starts to cradle the centripetal force will keep the ball in the pocket of the stick.

The force of the thrown ball will vary on its journey to the target The mass of the ball will always stay the same (is constant) The force the ball is thrown with will be directly affected by how fast the player is able to accelerate their stick. The stick holds the ball, therefore when the stick is accelerated, the ball is too

Without this law any pass thrown or shot taken would not be able to be stopped. When a pass is received an opposite and equal force goes against the incoming ball and is produced by the mesh of the stick The equal and opposite reaction will stop the ball and allow the player to catch it When shooting, the back of the goal provides the reaction which stops the ball from continuing When the defender checks the offender’s stick, an equal and opposite reaction occurs, and both sticks move in opposite directions (this law applies to checking too).

Videos to support this table:

1. My father shooting a lacrosse ball:

As you can see in these videos, the back of the goal stops the ball. However, what happens when the ball is not thrown into a goal, but just out into the open?

In these videos, you see that there is nothing stopping the ball. This is until eventually gravity pulls the ball down. 

Interesting Fact: When filming, my dad got a new personal record for throwing distance, throwing somewhere around 100 yards!

2. To further prove that gravity will bring the ball down, I had my father throw (with his stick) a lacrosse ball up in the air; I also threw (with my hand) a lacrosse ball into the air.

3. This is a video of my dad cradling. You can see that the ball is on the ground, and is not moving. This is an example of static friction. The ball will not move until an equal and unbalanced force (in this case my father) scoops up the ball, sending it into motion. 

After scooping the ball, my father draws it into a cradle, allowing it to stay in his stick.

4. Sadly, we did not get any videos of checking :(

This project was a lot of fun to work on, and I not only enlisted the help of my father, but also the help of some of my friends, thus adding a personal aspect to the project. Overall, I got clips of three sports, they were: Lacrosse (of course), field hockey, and archery. Out of this blog writing I want to send one message, so remember: 

If you learn the physics of a sport you play, the science behind it can help you improve.