Sorry, but I have to disagree with you. If the spin axis is below the direction of the ball, then the Magnus force will be sideways, not up/down. It really isn't a matter of opinion. It's a matter of physics.
They both travel the same distance. The pitch speed and bat speed are identical. Assuming both are "squared up" identically, the ball will come off the bat with the same speed, independent of who is swinging the bat. The main point is that the batter's hand, arms, body,... do not matter once...
I am guessing that by "geometry" you mean the spin axis. A small tilt of the axis one way or the other will determine whether the ball breaks left or right.
Not for the laboratory experiments, which are done under climate-controlled conditions. The scatter of the data due to the difficulty of the experiment account for the 20%. Now, in a game situation, the wind speed and direction does affect the movement, so that introduces even more...
The spin calculation..that is, the rate of spin (RPM)..that PITCHf/x reports is just an estimate, based on the amount of movement that is measured. The estimate is based on laboratory experiments that relate movement to spin rate. Those experiments are hard to do with great precision (I know...
While I agree with what you are say--namely, the pitch type is determined after the fact entirely from an analysis of the trajectory, without knowing what the pitcher or catcher intended, it is actually the case that MLB pitchers have used PITCHf/x to analyze their own pitches. Ex-MLB pitcher...
That's an interesting question. I think the movement of the two pitches would be the same, assuming pure backspin in both cases. It *might* be the case that there is a little less drag on the 4S. If it were indeed true, then the 4S would be a bit faster (assuming the same release speed)...
Just to be clear: I am not saying *all* split-finger fastballs move the way the Garcia's did. In fact, it is quite the opposite. It was the unusual nature of that particular pitch that led to the study that Cross and I did. In fact, I scoured the PITCHf/x database to find other examples of...
There is a *huge* body of pitch-tracking data from MLB (using the PITCHf/x system) showing that a 2S and 4S fastball move differently. The primary difference is that the 4S is throw with the spin axis very close to 6-12 (i.e., nearly pure backspin, with a little sidespin due to arm slot)...
Sorry, I should have used "Reply With Quote", so you could figure out what I was responding to. I've now been through the entire thread. Let me sum up. I fully endorse what JJsqueeze has said. However, I will remark that for baseball, the kind of movement that we see on the Garcia pitch is...