e - j o u r n a l
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11.7.00 class
Today I found a spot to conduct my experiment. I found a black backdrop and strung it on the wall hooks of the lab. I also located a tennis ball and basketball to use in my experiment.
11.8.00 class
Today I did a sample lab on the computer. It taught me how to calculate the speed of a moving object using Video Point 2.1 and Graphical Analysis. In order to the speed measurements before the collision and after the collision, I will be using the 2 frame before and after the collision to approximate the velocities of the balls. I will be recording whether or not the bounce was good or bad on a motion picture camera. In my next session I hope to start taking motion pictures of the colliding balls.
11.13.00 1:00-3:20
Today I took several pictures of a colliding basketball and tennis ball with the Canon Optura motion picture camera. The camera was 5.1 meters away from the subject. All the pictures were taken with a exposure of –8 and a shutter speed of 30. I had 3-4 collisions that seemed like the tennis ball shot straight up instead of at an angle. The tennis ball was 6.5cm in diameter and the basketball was 23.5 cm in diameter. Next time I will upload the videos and analyze them with Video Point 2.1.
11.14.00 class
Today I uploaded the video and found that I made an
unfortunate mistake. I knew that the shutter speed of 30 would not be quick
enough to capture a high-speed collision like this but yet I overlooked that
fact. My best guess at this point would be to re-take pictures at a shutter
speed of about 500. Next time, I will take several more pictures and upload
them. Hopefully this time I will have obtained pictures I can work with.
11.15.00 10:45-11:45 lab & class
Today I uploaded my second video clip. The zero exposure and the 500 shutterspeed helped me obtain better photos so that I can carry out my measurements. The video clip looked nice. I used Adobe Premiere to cut out my best bounces. Then I used Video Point 2.1 and obtained the data, the y-position of the ball before/after the collision vs. time and plotted it on four different graphs, two for the basketball and tennis ball. I fit a quadratic model to each one.
I’m not really sure how to go about doing the calculations for measuring the velocity but I will learn shortly. The Cannon Optura camera is very hard to focus correctly. But hopefully soon I will be able to explore the artistic standpoint, after I finish with the physics value of my project.
11.16.00 class & 10:30-12:00
Today I took another video and plotted the points of the basketball and tennis ball each with Video Point. Then I created a graph for each one using Graphical Analysis. Dr. Winters and I had a talk about what the quadratic fit meant. We discussed the physics variables compared to the Graphical analysis variables. After I analyzed each graph, some of my number seemed a little odd. My acceleration before the bounce was approximately 9.8 but the acceleration after the collision was not 9.8. Next time I hope to examine my graphs closer with Dr. Winters and obtain better shots of the balls.
11.20.00 lab & class
Today I took more shots of my bouncing balls. This time I laid the camera on its side so that I would be able to get more of the projecting balls. I uploaded the clips and cut out the clips that were usable. This time, just as I predicted, I got more frames of the tennis ball after the collision. The only inconvenience is that you have to turn your head side ways in order to view the dropping affect. In all, I can’t wait to plot the balls on Video Point and observe the quadratic fit.
11.22.00 class
I didn’t have much time, but I did manage to plot and get the graphs for the basketball and tennis ball after the collision. It helped to have more points but not enough. I hope to look over the videos one more time. I have to get started on my lab write-up and web page soon.
11.28.00 class
Got started on web page. Hope to do some more web page editing.
11.29.00 lab & class
Edited more of my web page. Hope to get started on my lab write-up.