Two Worlds on a String ;)?

Question

Two balls, A and B, with masses m_a and m_b are connected by a taut, massless string, and are moving along a horizontal frictionless plane. The distance between the centers of the two balls is L. At a certain instant, the velocity of ball B has magnitude v and is directed perpendicular to the string and parallel to the horizontal plane, and the velocity of ball A is zero.

Find T, the tension in the string.

Express T in terms of m_a, m_b, v, and L.

thx for trying Helmut but you are wrong.

variable v_b is not even supposed to be part of the answer

Answer 1

Taking (0,0) at ball a
T = MbVb^2/L