6. During Charlie's golf drive, the angular velocity of his club is zero at the top of the backswing and 20 rad/s at the bottom of the downswing just before ball impact. The downswing lasts 0.20 s, and the distance from the club head to the axis of rotation is 2.0 m at the bottom of the downswing. a. What is the average angular acceleration of the club during the downswing? b. What is the linear velocity of the club head just before impact with the ball