Jon Clarke writes, “As an avid cyclist and physics teacher, I had a tattoo a few months ago on my calf, and wondered whether that would fit with your archive. Having been given a cycle computer a year ago, I was frustrated and surprised that no matter how hard I cycled–on a level road without a tailwind or fast-moving large vehicle to shadow–I could never reach the UK speed limit in built-up areas (30mph). After some thought, I concluded that the dominant effect, and therefore limitation, was the power required to overcome aerodynamic drag for turbulent flow.”
In this tattoo, v is the speed of a bicyclist, and P is the rate at which muscles have to do work in order to overcome air resistance. If you double your speed, you have to work eight times harder. It is, in other words, a tattoo of human limitation.