Posted by: Bulldog () on Fri Apr 4 18:39:30 2008

BAT BARREL SEPARATION SPEED CRITICAL
Note: The last equation at the end of this post matches Adair's "Physics of Baseball" stated velocities of, pitch speed, bat speed, and baseball's COR to obtain the Adair's stated baseball velocity to travel 450ft.

Being a student on girls’ softball, also men and ladies golf, a major concern is bat speed when the ball decompresses and is thrown (separates) from the bat/golf club. Softball girls are not strong and must withstand the impact of a heavy softball, and in golf because the ball is not pitched.

(From the golfing machine by Homer Kelly, The proportion for the separation rate to the approach rate express the elasticity involved, and is called the Coefficient of Restitution which is 80% for the better golf balls—but drops below 70% at high speeds.) This would be with a dead center hits. (Note: Adair’s Physics of Baseball: I believe give baseball’s COR around 55% with loss of 30%, which equates to about 38.5% COR. I believe Adair states the bat decelerates by 30%.)

The faster the pitch the more brace and power the batter must have. With girls, if the arms/bat are not connected (Arms close to body) the impact force will do the following to the bat: stop barrel: shove barrel up (ball down): shove barrel down (ball up). I have video of this from the local teams to USA World cup teams. Also have a picture that shows a baseball bat bend back at impact (maybe a illusion maybe not?). Just think if you throw a rotating bat at a ball and it makes perfect solid contact how far will the ball go? Will the bat fall dead.

How well can slim wrists withstand the impact forces? To me that is a reason to have maximum bat speed at impact with the impact as deep (arms close to body) as possible. To me the more braced the arms/bat are, and the less barrel defection up, down, or rearward. That equals more solid contact up or down and more barrel speed at ball separation. The goal is not acceleration through impact, but preventing deceleration.

The faster the pitch the more the impact force and the slower the barrel separation speed.

Measuring ball speed hit from a tee would be the best way to measure power of the swing.

In golf, many amateurs have a lot more club head speed than the pros at impact but lose too much clubhead speed from impact.

Examples of separation/pitch/contact speed.
R=coefficient: P=pitch speed: I=Barrel speed at impact speed: S=barrel speed at separation: B=Ball speed at separation.
B=S+(R*P)+(R*I) {Note: B equals 100% of S and 40% of P and 40% of I}

S R P I = B {NOTE: S, P, I ARE IN MPH}
20 40% 30 50 =52
25 40% 30 50 =57 {NOTE: 5 MPH OF S = 5 MPH OF B}
20 40% 30 55 =54 {NOTE: 5 MPH OF I = 2 MPH OF B}
56 38.5% 85 80 =119.5 (using Adiar’s Table 5.8 =450ft )
{(PP 105, Adiar’s est. of Gorbous’s 446ft throw =115+MpH}
A Coincidence?

something to think about.
Bulldog