I was watching a SciFi tv show where large objects had an outer speed limit of 18000 kph and that got me wondering what things in everyday life are faster than even 500 kph.
I know bullets can be fast, but they are not exactly everyday life (at least in my life).
I included mass for obvious relativistic reasons.
Let’s break it down…
The distance, between the traffic light and the cab driver, should be approximately 10 meters.
The time light needs to reach the cab driver’s eyes is:
D ÷ c = 10 ÷ 299,792,458 = 0.0000000333… seconds = 0.0000333… milliseconds
The distance between the cab’s horn and your ears, should be approximately 5 meters.
The time needed for the cab’s honk sound, to reach our ears is:
D ÷ u = 5 ÷ 295 = 0.0169491525 seconds = 16.9491525 milliseconds
If the cab driver had a reaction time of zero, it would still take 16 milliseconds for us, to hear their honk.
The conclusion is that cab drivers have a negative reaction time, so that they can honk before the light turns green, breaking causality.