1. The problem statement, all variables and given/known data Two identical objects with the same initial speed collide and stick together. If the composite object moves with half the initial speed of either object, what was the angle between the initial velocities? 2. Relevant equations Law of momentum conservation: m1v1 + m2v2 = (m1+m2)v_final 3. The attempt at a solution I attempted to look at the momentum conservation equation to see if it's possible to incorporate angle. Looked at the dot product as well (v1 dot v2) but it does not make use of the information that the final speed is half the initial of either object so it must be wrong. I am basically blank-minded at this point. Please guide me through. Thanks for your help in advance.