THE 'SWEET SPOT' OF A BASEBALL BAT

摘要

In this study,"sweet spot" is first explained,the bat is assumed as a vibration elastomer,and the movement of particles in the bat is considered as comprised of the planar motion along the axis and the vibration perpendicular to the axis. Then,the bat-ballcollision process is divided into two sub-processes: (1) One is from the contact moment of the bat and the ball until the moment when they have got the same velocity; (2) the other is from the moment when they reach the same velocity until the moment when they are entirely separated with each other. Furthermore,the physical model is also established with a kinetic energy function whose variable is the location of the hit point. Eventually,several empirical data are substituted into the proposed model to conduct sensitivity analysis,and it is found that the "sweet spot" varies with the location of the grip point. Sweet points are found (6. 75 inches from the end of the bat while holding at the location 6 inches from the opposite point) through sensitivity analysis.