Lacrosse in the snow

For this post, I decided that I would work with my friend Starr to do a projectile motion problem. So for this activity, I threw her the lacrosse ball which she caught then took a shot in the net. This is something we both commonly do when she needs to practice shooting for lacrosse season. After doing this we experienced some technical difficulties, so I reshot it with my dad and brother.

Before my dad and I filmed, I measured the distance between me and him as well as him and the net. I also measured his height plus the height of the net he was holding it when he caught the ball which was approximately 5.7 ft. Using the information plugged into LoggerPro the initial velocity was around 10 m/s. 

Data

                X                                                      Y

▵X       20 ft                                                   5.7

Vi=       vicosθ                                               visinθ                           

Vf=         

a=            0                                                     9.8                                       

t=          1.77                                                 1.77

Then I plugged the video in to LoggerPro and obtained the graphs as well as compared the numbers and answers. 

                        Graph 1. Y(ft) versus time                          

Graph 2. Y(ft) versus time

 Graph 3. X velocity versus time

acceleration: -5.9 m/s^2

 Graph 4. Y velocity versus time

acceleration: -9.5 m/s^2

Conclusion: 

After plugging this in to LoggerPro the data makes sense in accordance with most of the data. The x acceleration would be close to zero because it is not accelerating in the x direction. However, in the Y direction the force of gravity is -9.8 which makes sense with this graph because the force of gravity is pulling the ball down. However, the variables with this data is that it was a video with limited measurements which could have lead to various mistakes in the arithmetic. Furthermore, when computing to find the angle the initial velocity was estimated based on the original points in the LoggerPro app. Similarly, the height of my dad with the stick and the distance in the x direction were slightly altered when put in LoggerPro. 

Force Application 

The second half of the video would be solved in a similar way, but since the tape measure was in a different angle, the LoggerPro was not as accurate. The only difference is with the stick, the ball is thrown downwards with force. The force that my dad acts upon the balls allows it to shoot downwards with a higher speed. Based on the force of the tennis ball, the velocity of the ball would increase or decrease. If you were solving as a projectile problem you would just account for the angle the ball was thrown at, as well as the distance and time.