Puck 1 sliding along the x -axis strikes stationary puck 2 of the same mass. After the

Question:

Puck 1 sliding along the x -axis strikes stationary puck 2 of the same mass. After the elastic collision, puck 1 moves off at speed v1f in the direction 60.0° above the x-axis; puck 2 moves off at speed v2f in the direction 30.0° below the x -axis. Find v2f in terms of v1f?