Whereas at the top of each bounce the ball slowly loses momentum turning its kinetic energy into potential energy until it reverses direction and begins to drop. The ball takes a longer time to achieve this as can be shown by the larger amount of plotted points at the top of each bounce when compared to the bottom of each bounce. This greater amount of recording at the top of each bounce enables a more accurate reading of what is perceived by this data to be the top of each bounce. The proportion of lost energy is given by h /h and so on.
The general rule for this is shown below: This has cancelled down to just H because M and G are just constants in this case which means that and when divided by each other than simply cancel out to form 1. I have now taken my raw data and made a table of all of the peaks, shown below:
This table highlights that the % of the previous bounce height reached by the ball is on average round about 85. 49% (2d. p) when excluding the peak six result. This result is over 6% of the mean of the other numbers which would indicate that it is an anomalous result, If it were to be included in the mean it would lower the result to 84. 21% (2d. p). If I had more time it would be nice to get some more results from the same experiment to find out if this result really was wrong, however the graph below also indicates towards a false result. These results when plotted on a graph with a line of best fit give the show a linear relationship.
Which would indicate that this is a constant figure, with more results I would have obviously got closer to this result as I could average the results to lessen the impact of anomalous results. To indicate how close this result is to the others I am going to work out the average distance away from the average and compare the result i. e. the standard deviation. Now I can work out the standard deviation which is:
The standard deviation is 2. 62 (2d. p). Despite the fact that there will be some small rounding errors the result still shows that the anomalous figure of 79. 085 is roughly twice as far off the average result as most other figures. This may because of a program error, because the camera has not caught the apex of the curve in the footage causing me to plot a lower point and as a result get a lower returning height. This result may also be due to an error with the programming, If I for example placed the point to low when plotting the points in the program. I worked out how far in cm I would have had to have misplaced the point from the average to cause such a degree of error the answer was 1. 56826 (working shown below).
This is a plausible answer to the problem. It may also be explained by interlacing. This occurs because of the way the camera works. It takes two images and combines them for every frame for example if a video camera has 600 video lines every other line would take the image (300 lines) this would be processed and then the other 300 would take an image this is to help the camera process the information. However if an object is moving at great speed then the camera frame can have two balls which are split into lines.
You must choose just one ball and plot it. But just after impact it can be hard to tell which ball is the correct one, as one can be going into the bounce while the other exits and it is hard to distinguish. This may also have caused the error. When the ball hits the floor and stops, that energy has to go somewhere. The energy goes into deforming the ball — from its original round shape to a squashed shape. When the ball deforms, its molecules are stretched apart in some places and squeezed together in others. As they are pushed about, the molecules in the ball collide with and rub across each other causing a build up of heat, and although immeasurable in this experiment it can be used by dropping Lead shot in a cardboard tube.
Some energy is also lost through sound. CONCLUSION From this experiment I can conclude that yes the same proportion of energy is lost per bounce irrelevant of height. I can say that this is a constant of around 85. 5% for this material. I can say this because I have carefully analysed the data and its limitations for example, I did not have enough readings at the base of the bounce to properly analyse the velocity to find out the kinetic energy. So instead I worked the result out using the 1potential energy at the apex of the curve. I also worked out which and why certain bits of data proved to be anomalous.
With more results I could have got a more exact figure for this material but I feel that The results which I do have indicate towards the correct figure and are on the whole consistent despite the limitations of the video footage. After looking on the internet I have found the results for glass on glass and the return height for this is 96%, with steel on glass this result is 90%. This result is interesting because it shows how much more energy is lost from a rubber ball that glass or steel.
BIBLIOGRAPHY source: ADVANCING PHYSICS Author: Edited by Jon Ogborn and Mary Whitehouse Published: 2nd Edition 2001 Publisher: Institute Of Physics Publishing’s Source: www. exploratorium. edu/baseball/bouncing_balls. html Author: Paul Doherty Published: 1997 Source: www. phys. hawaii. edu/~teb/java/ntnujava/bouncingBall/bouncingBall. html Author: Gfu-Kwun Hwang Published 1997 APPENDIX RAW DATA DIRECTLY PRINTED FROM MULTIMEDIA MOTION Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.