Quote Originally Posted by MrPrena View Post
Only thing it eventually stopping those 2 masses are gravity (g=9.8m/s^2) when it hit the ground some day.

Now, if those 2 items were thrown in the space without any gravity affecting it, it need reaction of same force to stop them.
Yes, but if they were thrown in space around earth they would need a lot more velocity thsn 40mph to not fall back down.