Posted by: MissouriDad (zach3737@aol.com) on Wed Dec 22 22:09:13 1999

Jack,
You started a topic about 10 days ago where you noticed that sometimes the ball is hit harder by a swing that didn't have as much velocity. And you posed the question, is there more at work here than bat speed? My first thought was, and it still is, that yes Force plays a role as in mass x acceleration. I thought one poster was going to hit the nail on the head when he brought this up but he turned his attention to mass (as though the entire body/bat system made a difference in mass. The attention needs to be on acceleration, I'm not talking about whether the bat is going from 82 mph to 86 mph at the time of contact. I'm talking about the acceleration that is present in force, an example of such acceleration is in an isometric exercise. I set out to prove this by starting with this: If velocity is the only thing at play here then the balls exit velocity would have to follow the laws of conservation of momentum. So I said what would be the exit velocity of a purely elastic impact of a 30 oz bat traveling at 85 mph and a 5 oz ball traveling at 85 mph. Again assuming it was perfectly elastic (no loss of energy due to deformation, heat, etc..) I got an exit ball speed of 206 mph while the bat would continue on at 36 mph. First this told me that the impact was definitely not perfectly elastic. I'm hoping to work with you on this. Do you have any data on bat speed immediately after contact? How about exit ball speed relative to bat speed? What kind of calculation do you think Paul Nyman uses to calculate the distance a ball will travel based on bat speed and bat weight (his devices display this info)? Do you think that 30 oz is actually hitting the ball? What if the bat were held by the barrel and the handle was swung? Obviously all 30 oz are not involved in a momentum calculation. Any thoughts here, do we use center of mass and distance from this center?
I bet we can kick it around and find there is more than bat speed at play here.