Posted by: Jack Mankin (MrBatspeed@aol.com) on Wed Jan 13 12:46:00 2010

>>> Not sure if you thought about a search feature on the site but I want to search Bernoulli to read some posts about backspin on a batted ball.

Based on your research where is the best place to hit the ball and at what angle to produce the longest hits? <<<

Hi Torque

We considered adding a search feature but I find Google worked just as good. A search for - batspeed.com+subject - usually finds the topic I am looking for. As an example, a search for "batspeed.com+Bernoulli" produced the following thread - Re: Baseball vs Softball Swing Plane

In that thread, I stated: "Rather than delving into the physics of why an up-slope can hit a ball (baseball or softball) farther, I decided to just look at the swing plane of balls hit a great distance. I reviewed tapes of a baseball home run contest and a slowpitch game between the Slowpitch-All-Stars and Major League Baseball players. --- I could not find a single home run (baseball or softball) where the bat was angling downward at contact."

In response to your question, let us examine the physics of why a bat angling upward at contact produces the "longest hits." -- Physics has determined that a hit ball attains its maximum flight distance when it exits the bat at about a 35 degree upward angle. Read: The Physics of Baseball

"Back-Spin" is produced when the ball is struck below its center-line. The lower the ball is struck, the greater the back-spin. Although the Bernoulli factor is important to ball flight, we must also consider what effect striking to ball off-center has on bat/ball momentum transfer during contact. When a ball is struck off-center, a vectored portion of the bat's momentum is deflected - ball deflected up, bat deflected down. The farther the ball is struck off-center, the more the bat's momentum is deflected rather than inducing exit speed to the ball.

As an example, let us consider a swing plane that is level in the contact zone. For the ball to attain its maximum flight distance, the ball must be struck low enough to deflect it upward 35 degrees from the bat's path. If the bat were on an up-slope of 20 degrees, the deflection upward would only need to be an added 15 degrees. - Now consider a bat angling downward 15 degrees. The ball would need to be struck low enough to deflect it upward 50 degrees from the bat's path.

Therefore, the lower the ball is struck, the greater the back-spin but also the lower the ball's exit speed. I would guess that a deflection of 10 to 15 degrees would produce the best 'back-spin/exit speed' ratio.

Jack Mankin