“A penny dropped from a skyscraper can kill someone.”

The idea that a penny falling from a great height, like a skyscraper, could become a deadly projectile is a long-standing urban legend. This misconception likely arises from our natural understanding of gravity, where objects accelerate as they fall, leading to the intuitive, but incorrect, conclusion that more height equals more speed, and thus more danger. The dramatic image of a small coin gaining immense destructive power also makes for a compelling, albeit untrue, story that is easily shared. People commonly believe this myth due to an exaggerated sense of the power associated with tall buildings and a misunderstanding of how air resistance affects falling objects.

However, the laws of physics tell a different story. While gravity certainly pulls a penny downwards, another crucial force is at play: air resistance. As the penny falls, the air pushes back against its movement. This resistance increases with speed until it perfectly balances the force of gravity. At this point, the penny stops accelerating and reaches its "terminal velocity". For a small, light, and relatively flat object like a penny, this terminal velocity is surprisingly low, typically between 25 and 50 miles per hour, and it's achieved after falling only about 50 feet.

So, what would it feel like to be hit by a penny traveling at terminal velocity? Rather than a lethal blow or an object that could embed itself in the ground, it would feel more like a sharp flick or a minor sting, perhaps leaving a small bruise. Its small mass and flat shape prevent it from ever reaching speeds that would cause serious harm, let alone be fatal. The dramatic effect of air drag ensures that the penny remains a harmless, albeit fast-moving, piece of currency, effectively debunking a popular and persistent myth.