Is there such thing as a “fatal velocity” for a human being?
In the era of the earliest automobile, people thought it was around 25MPH. In terms of relativity, there is no such thing as absolute velocity. You’re traveling faster than the speed of light relative to some object on the opposite ‘side’ of the universe. If you mean how fast can you be moving when you hit a solid object, that’s not so simple. People have survived free-fall at very high speeds. If you’re in a very conservatively-designed vehicle and you hit a brick wall at 60MPH, you could easily survive. If you trip and hit your head on a rock at 4MPH, you could die. The conditions under which you are safer without a car seatbelt than with one are exceedingly rare.
