Suppose m1 = 9.52 kg, m2 = 11.99 kg and vf = 5.71 m/s. If v1i = 10.1 m/s, what was v2i

Need to know the whole problem.

Did they collide?
Did the two stick together after collision?
If so
Conservation of momentum
m1 (10.1) + m2 (x) = (m1+m2)(5.71)