Physics of ball sports (original) (raw)

Ball sports have been part of human history for thousands of years [1]. Nowadays, 13 of them are part of the Olympic games (badminton, basketball, beach volley, football/soccer, golf, handball, hockey, rugby, table tennis, tennis, volleyball, water polo, ice hockey). All these games differ by launcher (hand, club, racket, bat), ball (size, shape and mass), pitch size and number of players. These differences induce different ball velocities. Apart from the velocities and the way to maximize them, we discuss in this article the ball trajectories and their impact on the size of sports fields. EPN 47/3 PHySICS OF bALL SPORTS FEATURES 14 Velocity in ball sports One challenge shared by all ball games is to produce the fastest ball. This allows players to reach larger distances or to outpace their opponents. Figure 1 shows the record velocities in different ball sports. At the bottom of the ladder, one finds shot-put, handball and basketball, for which the ball is launched by hand at roughly 15 m/s. Increasing speeds are recorded for volleyball (37 m/s) and soccer (62 m/s), for which the ball is hit by hand or by foot. Another way to increase velocity is by using an instrument to propel the ball: a bat (54 m/s for baseball), a racket (73 m/s for tennis), a chistera (86 m/s for jai alai) or a club (91 m/s for golf). At the top of the ladder stands badminton: in 2013, Malaysia's Tan Boon Hoeng set a new record with a smash at 137 m/s. The first part of our discussion is dedicated to the physics associated to this velocity ladder. Throwing vs. hitting m FIG. 3: (a) Soccer kick. (b) Chronophotography of a smash in tennis by Stanislas Wawrinka. (c) Chronophotography of a smash in badminton by Michael Phomsoupha.. FIG. 4: The two main trajectories observed in ball sports: (a) parabola, (b) Tartaglia. (c) Ratio of record velocity and terminal velocity. (d) Size of sports fields vs. maximum ball range.