Posted by: Jeff M () on Fri Nov 3 18:09:44 2006

Jack & BHL,
Proper swing plane or arc of a curve and the baseball swing are actually very easy to duplicate if you stop and review the basis for a dependable and repeatable swing. I think this is the driving motivation behind countless golf teachers; where they preach the perfect repeating swing. Main problem when applied to baseball is that one little “obstacle”, namely the pitched ball, which I think is less likely to cooperate than a motionless golf ball. BHL and Jack must first start with a basic understanding of rotational dynamics, and investigate in detail the rotational motion of objects and effects that forces have on motion. Jack is always talking about swing plane, but first he must analyze the rotation of a point particle. Start with the mass of the moving bat in an x-y plane with a force vector applied in that plane of motion, and of course a velocity vector, tangent to trajectory. Then look at the linear momentum vector, the radius vector of curvature of trajectory, set normal to trajectory and the angular velocity vector against the angular acceleration vector. Next is angular momentum (set parallel) and torque associated with the force of motion. We won’t try to reduce the answer from a factor to complicated for batspeed.com, but we will look at the resultant exit bearing based on our models of a swing used in a dynamic or better yet real-world equation (three seperate radius points) + batspeed equal to 85 mph with a center collision of a non uniformed pitched ball (88 MPH) over the center of the plate with several different radius positions (5'-10" player, 6'-1" player and 6'-3" player). So Jack and BHL, what you need to understand is that the perfect swing plane (or perfect swing) is one where the exit bearing or trajectory of the post-collision out-going ball is roughly equal to a location directly in line with center-field, plus or minus a few degrees of bearing. Vertically and again based on faily simple expressons we conclude that the exit velocity and height allows for clearance of every major ball park. Other factors considered are of course curvilinear motion, diplacement, uniformed circular motion, and my boy Newton's first law. Jack; you need to get a spellcheck button on this site. Any one care to comment?

Jeff M