For your reference I used to wrote a mail to Prof.Allan Nathan Dear Prof. Allan Nathan: Sir, I am a baseball fan in Taiwan. I am very interested in baseball physics. From your research data on website, I got a lot of correct baseball concepts even I did not really know these complex physics equations. I have a question about the physics about bat-ball collision. I had read your paper on website about bat-ball collision. But, I am sorry that I can not realize these complex physics equations. So, I mail to you for help. Can you kindly tell me? In Taiwan, everybody thinks that if two balls with the same linear speed and different backspin speed are hitted, then the ball with higher backspin speed will be hitted farther than the lower backspin speed one. In other words, if we neglect the effect hit precision, a batter can hit a 90miles/hr 2500rpm backspin fastball to a HR easier than hit a 90miles/hr 1000rpm backspin fastball. I doubt the reality this baseball concept. Is this concept really?? Thanks!! Best Regards Allen He answered to me. Dear Allen, Actually, it is my belief that the pitched ball with the smaller backspin will be hit further. The reason is that backspin on the *hit* ball makes the ball go further, because of the lift on the ball. This is best seen in golf, where a low-trajectory ball with lots of backspin actually rises. It is much easier to get lots of backspin on the hit ball if there is less backspin on the pitched ball. If the pitched ball with backspin simply changes its direction, then the backspin becomes topspin. To make the backspin become backspin, the spin of the ball has to reverse direction. As a result, a pitched ball with topspin will go further than a pitched ball with backspin. Or, a pitched ball with lower backspin will be hit further than a pitched ball with higher backspin. ...alan nathan --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 220.130.44.130 ※ 编辑: benda 来自: 220.130.44.130 (04/01 18:11)