A friend of mine was on his third floor balcony and saw someone vandalizing a wall almost directly below on the ground. He wanted to throw a plate from the balcony at the vandal. How dangerous would this be? If each floor is about 10 ft and my friend and the vandal are of equal height, that's about a 20 ft drop, plus whatever speed he can throw the plate.... I know √(2 * (20ft / 3.281ft/m) 9.8m/s^2)= 10.9m/s, but I don't know if the throwing on top of that would be seriously dangerous. He thinks this is not a big deal but I find this reaction very concerning. I'm not sure how worried to be if another vandal ever showed up again. I wouldn't want them to get significantly injured.