A Hockey Puck of Mass M Traveling Along the X

Multiple Choice

A hockey puck of mass m traveling along the x axis at 4.5 m/s hits another identical hockey puck at rest.If after the collision the second puck travels at a speed of 3.5 m/s at an angle of 30° above the x axis, what is the final velocity of the first puck?

A) 1.0 m/s, 30° below the x axis
B) 2.3 m/s, 50° below the x axis
C) 2.8 m/s, 60° below the x axis
D) 3.0 m/s, 45° below the x axis
E) not enough information