Posted by: SteveT () on Fri Dec 31 11:37:20 1999

Hi Jeff,

OK, here's the deal. My point is that even looking at it from a practical standpoint, the body mass is obviously out of the equation, because simple conservation of momentum gives us an accurate answer.If there were an effect from body mass, it would have to be very small, so who cares?

What the above is really saying is that the 140 MPH exit velocity is achieved by two free masses colliding. If the bat and ball collided in mid-air, the bat unattached to anything, this is what happens (it is not in dispute because conservation of momentum goes hand in hand with conservation of energy, and if that can be violated, you'll be able to design that elusive perpetual motion machine.) The absolute numbers may not be precise, but the idea is the same.

Now, what WOULD the effects of body mass be (if any?) Well, the bat would "recoil" (read:slow down) less. OK, fine. Then we can just increase the effective mass of the bat to achieve this and see what happens. At some point (when the bat mass is more than an order of magnitude larger than the ball), there is for practical purposes no bat recoil. At this point (mass= 50 ounces), velocity= 156 MPH. At mass= 500 ounces, V= 178 MPH.

Aside from the rather bizzare idea of 30 pounds of the hitter's body mass moving at the same speed as the bat (and being firmly attached, with the same characteristic frequency), how many people think they've seen a ball leave a bat at 178 MPH? Or even 156? The 178 hit could travel nearly 1,000 FEET. Even 140 MPH should scare the hell out of anyone who's ever pitched.

A little- known study (I'm trying to locate the abstract so I can post it here) conclusively determined NO effects from grip tightness with a wood bat. The effects of grip on an aluminum bat were such that without a firm grip, the aluminum bat responded just like a wood bat (trampoline effect is lost?) But this was in the "old days" of metal bats (circa 1989.) Tests with the Baum hitting machine also have given predictable results.

Bottom line? The name of this site- BATSPEED. Jack realized long ago that this was the key. Science confirms it. To quote a well-known sport scientist: "in all the world of sport, speed is King."