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一场激烈的棒球赛已近第九局的尾声。按规定,垒若被对方所占,则本队须退场一至数名击球手。此时球疾速飞来,至近处突然角度一偏穿过本垒,“多漂亮的香蕉球”,球迷们欢呼着。投球手是如何掌握这一绝技的呢?又是什么力量使球转向的呢? 对运动员、风洞进行的试验表明,球的转向是其自旋引起的。事实上,球转得越快,其偏转角度也就越大。一个漂亮的香蕉球在到达球棒或接手手套的过程中已旋转18次之多。当投球手发香蕉球时,他必须在球脱手之前快速转动一下手
An intense baseball game is near the end of the ninth inning. According to regulations, if the base is occupied by the other side, then the team must exit one or several batsman. At this time the ball flew quickly, suddenly to the point of a sudden through the home base, “more beautiful banana ball,” the fans cheered. How does the pitcher master this stunt? And what is the power to make the ball turn? Experiments on athletes and wind tunnels show that the ball’s turn is caused by its spin. In fact, the faster the ball is turned, the greater its deflection angle. A beautiful banana ball has rotated 18 times as it reaches the bat or takes over the glove. When a pitcher hands a banana ball, he must quickly turn his hand before the ball is released