So let's say there is a really tall building. Now this building has stairs that lead to the rooftop, similar to really big buildings in New York and stuff. So on the building there was a guy named Joe and Bob. Bob was lying on the rooftop (thanks for the help before) and Joe was standing. They were both near the edge of the rooftop (thanks Rudd). Now this is new info but Fred has run up the stairs to find the two on the rooftop. Once Fred gets there Joe picks up Bob... and THROWS HIM OFF THE ROOFTOP! Now according to the calculation done by I Heart Noobys, neglecting air resistance, it would take Bob 1.6 seconds to fall from this rooftop if the building was like 15 stories high or something. But somehow, someone jumps through the window to save Bob as he is falling! Now this person is really fast and can jump really high, he is kinda like a "hero". This "hero" jumps really high, catches bob, and ends up jumping high enough to get back to the rooftop. Now the "hero" is in a big hurry and THROWS Bob back onto the rooftop. So Bob hits the ground pretty hard. [b]So the question is: how hard would it hurt Bob? Would it potentially give him a concussion depending if he hit his head while landing?[/b] Now given the fact we don't know how fast the "hero" was moving or how hard he threw Bob, it might be hard to give a good answer. Just try and guess based on the personality of the "hero" (remember he is in a hurry) and any other factors that you believe may come into play. P.S. If you're having a hard time picturing the scene, the picture I created is a good representation of the moment the "hero" caught Bob. The building isn't to scale, though.