(1) Describe the concepts of tangential acceleration and centripetal acceleration in the windmill softball pitching movement; (2) What would these two accelerations be if the arm moves at a constant angular velocity? (3) Would the centripetal acceleration ever be zero? (4) In reality, would the arm move at a constant angular velocity during this pitching movement? How does this affect both tangential and centripetal accelerations? http://www.youtube.com/watch?v=kHqyS2LoNWc