An elastic ball (A) with mass m is released from a horizontal position, connected via a massless string to a rod. When the ball reaches the bottom, it collides with another elastic ball (B) of twice the mass, also connected via a massless string to the rod. How high can each ball swing, respectively? (The collision is total elastic.) Assume the +x direction is to the right
a)What is the velocity of ball A after the collision? (5pt)