Coefficient of Restitution of a Tennis Ball - International School ...

ISB Journal of Physics June 2007Calculation of Coefficient of Restitution:Equation:COR ≡v′v 0Example from Figure 5:1.65 m/s / 2.25 m/s = 0.73 +/- 0.06Table 1: Velocities and Coefficient of RestitutionTrialInitial Velocity(m/s) (+/- 0.09Final Velocity(m/s) (+/- 0.09)COR(+/- 0.06)1 2.25 1.65 0.732 2.40 1.74 0.733 2.40 1.53 0.644 2.40 1.75 0.735 2.41 1.75 0.736 2.72 2.07 0.767 3.16 2.18 0.698 3.28 2.19 0.679 3.60 2.18 0.6110 3.95 2.63 0.6711 4.05 2.52 0.6212 4.14 2.51 0.6113 4.21 2.52 0.6014 4.37 2.95 0.6815 4.58 2.94 0.6416 4.70 2.52 0.5317 4.72 2.74 0.5818 4.90 2.94 0.6019 5.01 2.94 0.5920 5.45 3.16 0.5821 5.52 3.14 0.5722 6.32 3.38 0.5323 6.59 3.56 0.5424 6.63 3.26 0.4925 6.66 3.38 0.51TrialInitial Velocity(m/s) (+/- 0.09Final Velocity(m/s) (+/- 0.09)COR(+/- 0.06)26 6.94 3.58 0.5227 7.13 3.62 0.5128 7.19 3.60 0.5029 7.44 3.83 0.5130 7.55 3.28 0.4331 7.57 3.73 0.4932 7.64 3.60 0.4733 7.64 3.71 0.4934 7.84 4.25 0.5435 7.86 3.60 0.4636 7.88 3.83 0.4937 7.89 3.62 0.4638 8.50 4.19 0.4939 8.66 4.50 0.5240 8.70 3.80 0.4441 9.29 4.31 0.4642 9.34 4.07 0.4443 9.72 4.37 0.4544 9.89 4.29 0.4345 10.05 4.67 0.4746 10.28 4.22 0.4147 10.94 4.60 0.4248 11.58 4.89 0.425

ISB Journal of Physics June 2007Figure 6: The graph above shows the relationship between the initial velocity and COR.Notice the clear decrease in COR over the velocity range between 2 and 12 m/s. A curve ofthe form predicted fits the data within uncertainties.Figure 7: The graph above is the same as the one in figure 6 except with curves fitted to theextremes of the data to estimate the uncertainties in the relationship.6