Momentum, a function of mass and velocity, is conserved between portals. In layman's terms, speedy thing goes in, speedy thing comes out.
Well done. Here are the test results: "you are a horrible person". I'm serious, that's what it says: "a horrible person". We weren't even testing for that. Don't let that "horrible person" thing discourage you. It's just a data point. If it makes you feel any better, science has now validated your birth mother's decision to abandon you on a doorstep.
You know what my days used to be like? I just tested. Nobody murdered me, or put me in a potato, or fed me to birds. I had a pretty good life. And then YOU showed up, you dangerous, mute, lunatic.