I don't have enough time right now to address all your points. However, let's first separate the discussion into two part: kunckleballs and everything else. Regarding the latter, all the tracking data I have seen (and there has been lots of it), whether softball or baseball, show that the trajectory is smooth and the movement is continuous. No exceptions found thus far. Regarding the former, most (not all) of the pitches I have analyzed show the same thing: smooth trajectory and continuous movement. However, there are exceptions where there are multiple breaks. The physics behind the movement of spinning pitches (the Magnus force) is different from the physics behind knuckleball movement. In the latter, it occurs due to the character of the air flow changing as it flows over the seams. For slowly rotating knuckleballs, there is a slowly changing seam pattern that can result in multiple breaks. For rapidly spinning balls, the seam pattern is changing so rapidly that the resulting force just averges to zero. Not so for the knuckleball.
Topspin Vs Bulletspin, Which is Faster?
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- Jul 26, 2010
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Interesting.
Do you think that since the softball is larger and experiences more deceleration than a baseball, that the same could be said?
-W
So the calculations use a 6.5" 12" smooth sphere (no seams) and the results have a margin of error of +/- 20%. Correct? That said would you agree that the numbers being discussed are more theory than real world empirical data?
No, I don't agree with your statement. There is currently no "theory" that can predict the size of the Magnus force for a given amount of spin and speed. The equations are much too complicated to solve for a complicated object like a softball. It may not seem to be complicated, and it wouldn't be if it were not for the seams. But the seams really do matter to get the quantitative details right. No one has yet solved the problem. The +/-20% *is* "real world", as that is the approximate scatter of real data. Just as the theory is hard, so are the experiments hard to do. So, if you compare different experiments by different researchers, you find a scatter of the data at that level. As Bob Adair (who wrote the superb book, The Physics of Baseball) once told me, "The physics of baseball isn't rocket science. It's much harder."
Interesting question. The softball loses about 8% of its speed over 39 ft (according to the WCWS data I have). That is comparable to the speed lost by a baseball over about 50 ft. So, the air drag is larger on a softball, the primary reason being that the size is larger. Example: Stick your hand out the window of your car while driving, with the palm facing forward. You will feel a considerable force on your hand. Now tilt your hand so the palm is facing down. You feel considerably less force. The area of the hand "seen" by the on-rushing air is a lot less in the latter than in the former. So, you are right that the deceleration is larger on a softball than on a baseball.
OK then, this is not matching up to my experience, but maybe there is another factor or combination of factors that I am overlooking. When I throw a curveball into the wind it definitely looks like it breaks more than when I throw it downwind. But when I launch the ball into the wind this equates to a faster pitch relative to the wind speed so it should break less. So if I throw a 60 mph curve into a 10 mph wind this equates to a 70 mph pitch with no wind, and if I throw a 60 mph curve with a 10 mph tail wind this equates to a 50 mph pitch. Yet it looks like the first pitch breaks significantly more. Unless throwing the pitch into the wind creates an effectively longer pitch making it break more. It's definitely got me scratching my head.
Believe it or not, this agrees perfectly with what I said. When you throw the ball into a 10 mph wind at 60 mph, the relative ball-wind speed is 70 mph, with the wind it is 50 mph. I expect a larger Magnus force with the 70 than with the 50 since the product of spin and "velocity relative to the wind" is higher. The other factor affecting movement is the flight time, but that is barely affected by the wind. In both cases, it is equivalent to about 60 mph, the speed relative to the ground. Bottom line: More movement throwing into the wind than with the wind, exactly as you said. That is not the same as throwing 70 mph and 50 mph without any wind. In that case, I would expect more movement at 50 mph. Does all this hang together for you?
Alan, I agree with you. But there are stubborn people who cling to the notion that a riseball is not rising, but is not falling as fast as other pitches. The spin on the ball will counter gravity's effect to a certain extent and the rise will be better than a non or less spinning upward arching pitch. The spin means a lot otherwise it is very easy to hit a high fastball.
Definitions are important when discussing physics. We use the terms "rise" and "drop", but the terms require a reference point.
If we use "ground" as the reference point, then all softball pitches initially rise (all softball pitches are thrown with an initial upward trajectory) and then drop to the ground (assuming you don't have a catcher catch the ball).
The riseball is higher at the plate than a fastball (whether the fastball has bullet or 12-6 spin) if both were thrown with the same initial trajectory, same release point and same speed. So, one way to describe the action of a riseball is "the riseball falls less than a fastball over the distance from release to the plate".
Personally, I prefer to talk about the riseball with respect to its initial trajectory. The riseball never moves above its initial trajectory. However, by the time it has reached the plate, it has deflected less from the initial trajectory than a fastball.
The riseball is actually a lesson about "pitching" as opposed to physics. Pitching is more about the deception of the batter than the movement of the ball. The reason good batters miss a thrown pitch is because they expect to be at one location when the ball is at another. (Hitting a breaking pitch is easier than hitting a fastball *IF* the batter knows the pitch is a breaking pitch. The pitch is slower, and the "hitting zone" the ball will go through is smaller.)
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