Will you please help me with this question? (physics)?

A 1.6kg ball is attached to the end of a 0.40m string to form pendulum. This pendulum is released from rest with the string horizontal. At the lowest point of its swing, when it is moving horizontally, the ball collides with 0.8kg block initially at rest on a horizontal frictionless surface. The speed of the block just after the collision is 3m/s. What is the speed of the ball just after the collision?