Originally Posted by TSJ55
Did you read your own references AD? Here'es a quote from http://www.acs.psu.edu/drussell/bats/cop.html Emphasis
added by me.
COP and the Sweet Spot - what location "feels" best?
So, there is pretty overwhelming evidence that the COP has nothing whatsoever to do with the measured performance of a baseball or softball bat.
However, from its definition as being the impact location that results in zero net force at the pivot point, the COP is still often referred to as being the "sweet spot" at least in terms of feel. Hitting the ball at the center-of-percussion on the bat should minimize the sting felt in the hands. Early research by Brody and Noble suggests that the best place for the ball to impact the bat with minimal force exerted in the hands is between COP relative to the 6-inch point on the handle and the node of the first bending mode of vibration. Robert Adair has long argued that its only the location of the node of the first bending vibration of the bat which influences feel. Rod Cross conducted numerous experiments on bats and tennis racquets and concluded that the most comfortable location is somewhere between the nodes of the first two bending modes, with the location of the node of the second bending mode being more important. The issue is somewhat controversial and has raised some interesting banter back and forth between holders of the various viewpoints.
It is true that the COP is the location where no net force is exerted at the pivot point. However, the recently discovered fact that the actual pivot point at the instant of collision is not on the hands under the handle, but about 2.5 inches completely beyond the end of the handle, renders the COP relative to the 6-inch point on the handle irrelevant. If the defacto pivot point during the collision is not on the handle, then there is no point on the handle where the net force is exactly zero and the COP is meaningless as a definition of the sweet spot.
Recent experimental evidence for hand-held tennis racquets[18-19] agrees with the results for baseball and softball bats. The location of the pivot point is not under the hands. Thus, the center-of-percussion relative to a pivot point on the handle is not representative of the actual playing conditions and cannot be the "sweet spot" location that feels best.
Do you seriously want to argue a point of basic physics? You claimed the COP does not move based on where you hold the bat. I proved it does.
Your out-of-context snippets show some scientists arguing over exactly how the sweet spot should be defined, but it doesn't change the fact that the sweet spot moves depending on where you hold the bat.
The salient and pertinent point is not about vibrations or hand sting or feel despite your obfuscations. The COP is the best place to hit the ball to maximize the force that is transferred to the ball
. Choking up on the bat moves the COP out toward the end of the bat away from the spot players have instinctively learned to hit the ball and reduces your margin for error. Choking up has been proven by physicists to be a dumb idea. It doesn't work. It gives you less leverage, causes you to hit the ball with less force (which means you are less likely to get a hit or especially an extra base hit), it reduces your plate coverage (making you more likely to strike out), and it fails to increase your likelihood of making contact (which defeats the purpose for doing it in the first place). Choking up is a losing strategy, always has been, always will be.