A 11 kg object and a 19 kg object are connected by a massless compressed spring and rest on a frictionless table. After the spring is released, the object with the smaller mass has a velocity of 12 m/s to the left.

Question

What is the velocity of the object with the larger mass?

Answer 1

The answer: Whatever it takes to make the total momentum of the two objects zero.

Their individual momenta will be equal in magnitude and opposite in direction.

Use that fact to solve for the larger object's velocity.