From the general and historical perspective in the definition of speed , let's have a look at the final two options: Velocity ( v ) or rather speed is now defined as distance by time or d / t , and measured in km/h , m/s , mph or something equivalent. Wikipedia : " Italian physicist Galileo Galilei is usually credited with being the first to measure speed by considering the distance covered and the time it takes. Galileo defined speed as the distance covered per unit of time. In equation form, that is v=d/t " However, I suppose Roman legions , comparing troop movements, and even ice age hunters used similar equations - it's a natural definition for a sentient being, at once a predator and prey , to cover movement in time and space , and defining it by the relation of distance to time . Speed , defined as distance by time or d/t , increases with distance and decreases with time . This worked for eons; we instinctively appreciate speed th...
Life, the Universe and Everything - and the real answer may not be '42'. To go where no man (or whatever) has gone before.