Asterix and Obelix are standing on skateboards on level ground 2 m apart. Obelix holds a ball of mass 1 kg. The mass of Asterix and his skateboard is 29 kg; that of Obelix and his board is 70 kg. Initially, everything is at rest; then Obelix throws the ball horizontally with an initial speed of 7 m/s toward Asterix, who will catch it and throw it back. We will ignore friction in the wheels and air resistance.
A) What is the center of mass?
B) in which direction will the center of mass move?