For this project we were assigned to choose an important action of a sport and find the physics behind it. My group, which consisted of Cole, Cris, Garrett, and me, chose to find the physics behind the ideal lacrosse shot. For those of you that don't know, lacrosse is a game played usually on a turf field by two teams of ten players each, in which the players use a long-handled stick that has a webbed pouch on the end to cradle and maneuver a ball into the opposing team's goal. For our project we created a video explaining the key elements that you need in order to have the ideal lacrosse shot. In the video we included the correct technique to shooting a lacrosse shot, detailed explanations for each step of shooting, and the calculations for each step used. Here is our video explaining the ideal lacrosse shot.
Steps of Shot and Major Physics/Engineering concepts
The key concepts we used in our project were finding force, mechanical advantage, velocity, acceleration, impulse, projectile motion, and torque.
Step 1 Torque of the Body: This increases the velocity by an average of 2 m/s by twisting your hips and putting your back foot behind your front foot. There are two major components of projectile motion, horizontal and vertical velocity. We calculated the horizontal velocity of the lacrosse ball. To calculate velocity you divide distance over time. We shot from a distance of 45 meters and the ball didn't hit the ground for 1.4 seconds. V=d/t V=45m/1.4s V=32.14m/s
Step 2 Arm Extension: Slide your elbow so it is equal to your chin which increases the height from which the ball is thrown. Based on our trials, this increased shot accuracy by approximately 25%.
Step 3 Top Hand Slides Down: This decreases the mechanical advantage which increases the velocity because the output distance was increased.
The lacrosse stick is being used as a lever to make the shot faster. To calculate mechanical advantage you divide the input distance over the out put distance. MA=input dist./output dist. MA=0.33m/0.66m MA=0.5 The mechanical advantage of the lacrosse stick is 0.5.
Step 4 Bottom Hand Exerts Force: The bottom hand exerts force towards the ground which launches the ball. To find the force exerted we multiplied the mass of the lacrosse ball by the acceleration of the ball. The mass of the ball was 0.141kg and the acceleration of the ball was 32.5m/s*. F=ma F=0.141kg x 32.5m/s* F=4.063N The force applied to the stick was 4.063N.
Step 5 Follow Through: The follow through increases maximum impulse. To calculate impulse we multiplied the force exerted by the time.
I=F x t I=4.063N x 0.73s I=32.22 kg*m/s The impulse of the ball is 32.22 kg*m/s
Step 1 Torque of the Body: This increases the velocity by an average of 2 m/s by twisting your hips and putting your back foot behind your front foot. There are two major components of projectile motion, horizontal and vertical velocity. We calculated the horizontal velocity of the lacrosse ball. To calculate velocity you divide distance over time. We shot from a distance of 45 meters and the ball didn't hit the ground for 1.4 seconds. V=d/t V=45m/1.4s V=32.14m/s
Step 2 Arm Extension: Slide your elbow so it is equal to your chin which increases the height from which the ball is thrown. Based on our trials, this increased shot accuracy by approximately 25%.
Step 3 Top Hand Slides Down: This decreases the mechanical advantage which increases the velocity because the output distance was increased.
The lacrosse stick is being used as a lever to make the shot faster. To calculate mechanical advantage you divide the input distance over the out put distance. MA=input dist./output dist. MA=0.33m/0.66m MA=0.5 The mechanical advantage of the lacrosse stick is 0.5.
Step 4 Bottom Hand Exerts Force: The bottom hand exerts force towards the ground which launches the ball. To find the force exerted we multiplied the mass of the lacrosse ball by the acceleration of the ball. The mass of the ball was 0.141kg and the acceleration of the ball was 32.5m/s*. F=ma F=0.141kg x 32.5m/s* F=4.063N The force applied to the stick was 4.063N.
Step 5 Follow Through: The follow through increases maximum impulse. To calculate impulse we multiplied the force exerted by the time.
I=F x t I=4.063N x 0.73s I=32.22 kg*m/s The impulse of the ball is 32.22 kg*m/s
REFLECTIONS
Overall I think the project went well considering that we didn't have the amount of time we would have liked to have and that only two of the four of our group members knew a lot about the game of lacrosse. Our group worked well together but we would sometimes get off task when we got side tracked. During this project I learned two important skills that I can benefit from for the rest of my life. First, I learned how to make and edit my own video which can be quite useful for future projects. Second, I learned how the concepts of physics affect every sport and having this knowledge I can improve and work on the sports I play by using the concepts I learned. There were a couple things that I could have improved on for future projects. First, I can stay focused more on the project and on my work than doing other things. Second, I can provide more ideas to the group and brainstorm possible solutions or come up with adjustments for what the group might need. The most challenging part of the project was editing our video. We completed this challenge by taking our time and not rushing the process. The part of the project I enjoyed the most was learning how each physics concept can affect certain aspects of a sport. Over all I thought it was a fun and solid project that helped me understand some of the concepts of physics a lot better.