Question

Object 1, which has mass 100 kg, is moving at 3 m/s and collides with Object 2, which has mass 50 kg and is moving at -8 m/s. If the first object stops moving after the collision, how fast would the second object be moving at that time?

I think the answer is -2 m/s.

Answer 1

momentum conservation
initial=final
100*3+50*(-8)=100*0 + 50*V
I agree with your answer.