# Spring transferring half its energy to each mass?

My question is:
Does a spring between two differing masses, each with an initial momentum of zero, transfer half of its stored elastic potential energy to each?

My intuition says yes. But it seems to not be the case. If you apply the conservation of energy and momentum, the answer you get is different than if you take half its stored elastic energy, give it to each object and calculate velocity.

If this is not the case, why?