Physics of Sports Video

Our Task

Knowing how to hit a tennis forehand is a crucial part in playing a tennis match. Once you understand the movements and physics behind it, you are well on your way to becoming a great player. For this project I was put in a group with Holden and Zackary. The assignment was to pick a sports action, film a video instructing how to complete it, and calculate different movements within the action. Our group picked hitting a tennis ball in a forehand position. Over a week and a half, we spent time completing this project.

Storyboard

This was the first draft for the video. We wrote down all of our ideas and modified the plans to what was feasible for our group.

Hitting a Tennis Ball: The Forehand

Scene 1: Intro to video and introduction of members

Scene 2: Show a video of someone hitting a tennis ball then start to explain the motions. (insert video of tennis player hitting)

Scene 3: Running to ball/ Setting your turn -show feet running and pan out to whole body setting turn

Scene 4: The Grip-show hands on racket showing correct grip

Scene 5: Dropping arm into swinging motion-show side shot of somebody moving their racket/arm

Scene 6: Swinging arm and hitting tennis ball over net and in bounds.-continue with side shot of body

Scene 7: Follow through-switch to other side of body showing the follow through

Script

After making the storyboard, we made a script. This is what we used to film the sections of our video:

Shows a person struggling to hit a tennis ball

Person A: “Hey, how do you hit a tennis ball correctly?” (Zack)

Person B: “Well, there are many ways of hitting a tennis ball but I’ll show you a simple forehand.” (Holden)

Person A: “Sure!” (Zack)

Actions are shown:

Person A then hits the ball exactly like how Person B did. (Zack)

During actions voice-over tells steps in detail

Hitting a forehand is one of the most important skills to know while playing tennis. Here are the basic steps needed in order to hit a great forehand:

1. First, set your turn perpendicular to the direction you want to hit the ball. Your feet should be just over shoulder width apart and you should grip the tennis racket in the semi-western forehand grip. Once you are in this position, you are in your stance. (Logan)

2. Once you are in your stance, extend your non-dominant arm and drop a tennis ball in front of you. The ball has a potential energy of (7.3J) and a velocity of (.98m/s).This mimics the action of a real life game. (Holden)

3. Once the ball is dropped, drop your arm back and then you should begin to drop your arm into the swinging motion. To do this, throw your arm back, drop it, and begin to swing forward when you get to an angle about 45 degrees from your back. (Zack) (1.1m/s being thrown at me)(3.3m/s when i hit it with the racket))

4. Swing your arm forward with a velocity of (v). Make contact with the ball in front of you. When making contact with the ball we had a force of (f). (Logan)

5. Follow through, dragging your right foot forward and swinging your racket to be above your left shoulder. (Holden)

Actions:

Person B holds a tennis racket up the camera and shows how to position your hand and fingers in the Semi-Western Forehand handling(Logan). A ball is thrown to Person B who goes to the ball, swings, and hits the tennis ball. Their foot positioning is shown and the follow through is shown. During this time a voice-over slowly explains the steps.

Calculations

Force of Impact: The force of impact is a force that delivers a shock or high impact in a relatively short period of time. It occurs when two objects collide. In our case, the force of impact was between the tennis ball and the racket. It was found by multiplying together the mass of the tennis ball(0.06kg), the change in velocity of the ball(14m/s), and dividing by the time of impact(0.01s). The force of impact when the tennis ball collided with the racket was 84N.

Vertical Velocity: Vertical velocity is the velocity of a falling object going up or down. To find the vertical velocity of the tennis ball, I multiplied together the acceleration due to gravity(9.8m/s^2) and the time of the fall(0.61s). The vertical velocity of the tennis ball when dropped was 5.98m/s.

Horizontal Velocity: Horizontal velocity is the average speed on a flat surface with no outside forces. To find the horizontal velocity, divide the distance the ball traveled horizontally by the time it took. You can also find the ball by setting up a right triangle problem. Below is how I set up the problem and solved. My horizontal velocity was 5m/s.

Total Velocity: The total velocity is the vertical and horizontal velocity combined. To find it, you can use the Pythagorean theorem or a^2+b^2=c^2. To solve using this method, you need to set up a triangle problem where the horizontal and the vertical velocities are the legs and you are solving for the hypotenuse. I solved for my total velocity using the equation to get 5^2+13.1^2=c^2. My total velocity was 14m/s.

Reflection

Overall, I think that my group did a good job on this project. Even though we didn't previously know each other, we all got along so it was easy to work together. I play tennis so I was glad we picked a tennis forehand because it was fun to find the physics behind the movement and to further improve my hitting skills. During this project I exemplified leadership and communication to my group.

I really showed my leadership skills during this group project. Again, since we aren't in person at school, it is hard to know everybody and it can be hard working with one another. I think I helped to lead our group and that made it easier for us to work together. Every morning that we had physics I would set goals for our group so we knew what we had to get done that day. Everyone in our group worked really hard to finish their parts so we ended up finishing early. This project also helped improve my communication skills. We had to all be on the same page about our video and how we were going to get it done. This took lots of talking to each other during zoom and emails during our asynchronous work time. During the Rube Goldberg project I had trouble reaching out to my group about their section of work, so this time around I took advantage of every opportunity to ask questions and help when I could.

Although I improved in my communication, I think I could have done a better job in empathy. Instead of reaching our to establish connections with my group, we didn't really have any conversations besides our group work. We worked nicely together but the conversations we had felt very forced. During our next group project, I will do my best to make deeper connections with my partners and make new friends.