If a penny fell from a really tall skyscraper, like the Burj Khalifa in Dubai, would it really fall fast enough to seriously hurt someone walking on the street? Luckily, the answer is no. Myth debunked! ...and then re-debunked? Dropping a penny from a really tall height won't make it into a bullet to a bird on the sidewalk, There's something called terminal velocity, which keeps the penny from gaining infinite speed. See, if its falling through a bunch of air molecules, so at a certain speed it can't push them out of the way any faster than its already pushing them. So from atop a tall building, your penny will be falling for longer at the same terminal velocity as if it would if dropped from, like, a five story building. But if you dropped the penny from a plane 39 kilometers high those air molecules are less dense. and since it would have fewer molecules to push, it would go faster, and be more dangerous to, like, a bird flying just below. Anyone on the sidewalk, though, would still be fine, because the penny would slow down as it reaches denser atmosphere.