San Antonio, Texas
June 10, 2012
June 10, 2012
June 13, 2012
25.201.1 - 25.201.12
Applying Dynamics to the bouncing of game balls: experimental investigation of the relationshipbetween the duration of a linear impulse during an impact and the energy dissipated.AbstractThis paper discusses experiments done as a class assignment in a Dynamics course in order toinvestigate the relation between the duration of a linear impulse and the energy dissipated duringimpact. After analysis had been presented in lecture on the relation between work and energy andon the connection between linear impulse and linear momentum, a series of distinct but relatedprojects was assigned as hands-on applications of the results of analysis.In project one, it was shown that the height to which a dropped ball rebounded depended uponthe height from which it was dropped. The ratio consisting of the rebound height divided by thedrop height was found to decrease with increasing drop heights. This pattern held true withbasketballs, tennis balls, ping pong balls, volleyballs, and racket balls. In project two, therebound height of a basketball was investigated as a function of the inflation pressure of thebasketball. It was determined that the rebound height increased with increases in the inflationpressures. In project three, experiments that would allow for the collection of data to help explainthe results of projects one and two were designed and carried out.First, the relationship between the mechanical energy dissipated by a ball bouncing off a rigidsurface and the duration of the impact was investigated experimentally. Three different kinds ofballs were used: basketballs, tennis balls, and ping pong balls. Data were collected using digitalcameras and processed using software freely available on the web.For each of the tested balls, experimental data showed that when the duration of impactsincreased, so did the amount of energy that was dissipated. Similarly, when the duration ofimpact decreased, so did the amount of energy that was dissipated. Consequently, for each testedball, the longer the duration of the impulse, the more energy was dissipated.The engineering curricula at our university are arranged in such a way that students usually takeStrength of Materials and Dynamics during the same semester. Such students reported that thisproject allowed them to start to see that relationships did exist among the energy dissipated bybouncing balls during impact, the deformation undergone by the balls, and the properties of thematerials of which the balls are made. The fact that students began to uncover such connectionson their own was very satisfying.
Njock-Libii, J. (2012, June), Applying Dynamics to the Bouncing of Game Balls: Experimental Investigation of the Relationship Between the Duration of a Linear Impulse During an Impact and the Energy Dissipated. Paper presented at 2012 ASEE Annual Conference & Exposition, San Antonio, Texas. https://peer.asee.org/20961
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