But that is not quite technically correct.
A curve ball technically accelerates because it changes direction ==> it gets going faster in that particular direction to which it is curving. This is an acceleration but does the overall speed of the ball increase from the time it leaves the pitcher's hand? If it does it would be pretty minimal and would require some fairly high powered analysis of the ball's flight to prove the overall speed was increasing. Perhaps this would be a good use for the wonderful QuesTech system!
Overall does the speed increase during flight... possibly, in a very minimal amount due to the spin of the ball but realistically, NO. A ball does not leave a bat at 100 MPH and increase it's speed so that by the time it is caught it is traveling 125 MPH. Quite the contrary is what happens; the ball decreases speed in the direction it is traveling due to the friction and drag of the air.
You can see this in the projected flight of a ball as it leaves the bat and climbs at a nice gradual angle but as it reaches the extent of its upward movement the descending angle in which the ball falls is much steeper than the ascending angle. This is because the ball has slowed down (due to air friction) and at this point in the flight, gravity has a much greater affect/portion of the ball speed than the original impetus provided by the bat.
Can the speed increase due to gravity be greater than the original speed? Not on a level playing field. Yes, if you hit the ball over a cliff where the distance the ball falls is much greater than the distance the ball rose into the air.
So in the sense that you asked the question the answer is no.
I think some of this talk about acceleration has to do with the materials of the bat (given that the COR, Coefficient of Restitution/Resiliency, of the ball is constant). A soft bat, such as a wooden one, dents in more and the dent rebounds back to its original shape more slowly - less energy is transferred to the ball and consequently the ball leaves the bat at a slower speed (for a given speed of the bat). A harder metal bat does not dent as much as the wooden bat and the dent's rebound is quicker - more energy is imparted to the ball and the ball leaves the bat at a higher speed ==> therefore quicker and farther flight and the need for quicker responses by the defense. It is for this reason that highly resilient bat materials become a safety issue for the infielders because they cannot respond fast enough to the increased ball speed.
Hope that helps and that I haven't confused anyone. Tony
[Edited by DownTownTonyBrown on Aug 4th, 2003 at 03:44 PM]