Fig. 34 The effect of initial velocity and spin on the final position of a baseball in the strike zone, when thrown on the same initial trajectory by the pitcher. Upper left: The position of the ball in the strike zone when thrown by a right handed pitcher on the same initial trajectory with varying velocity and spin. mph = velocity of ball as it enters the strike zone; arrow = direction of rotation as seen by the batter; rpm = revolutions of the ball per minute; (xx) = revolutions of the ball between the pitcher and home plate; rotation of knuckle ball varies. Upper right: Fast ball (red) compared to curve ball (green) as seen by batter over time (s). Lower: Fast ball (red) compared to curve ball (green) as seen by batter over time (s) as seen from the side. Note: the distance from the plate the slow curve is when compared to the fastball as it crosses the plate in 0.40 seconds and how the batter would see the curve ball as “falling off the table” in the final 0.18 seconds.476,733