If I’m a WWF Wrestler, and I sling-shot myself off the ropes, and my momentum carries me as I put a flying shoulder block on my opponent, is my momentum conserved and do I feel any momentum against me?
As you bounce off the ropes, you exchange momentum with the ropes (and the earth). As a result, you normally reverse your momentum and head back into the ring. When you hit your opponent, you begin to exchange momentum with him/her. If you hit your opponent feet first and jump backward, you will reverse your direction of travel again and your opponent will receive an enormous amount of forward momentum. All of this transfer of momentum means that your personal momentum will change often but the total momentum of the earth and its population won’t change. That momentum will just be rearranged amount the various objects.