Why are cops called 50?

Answer 1

Because of the old TV show "Hawai'i Five-O" - the 5-0 on the TV show just meant that Hawai'i was the 50th state.

An alternate answer, is - a decade after the show, police in California drove cars with 5.0 engines. the engine size was displayed on the side (by the manufacturer - Ford). it became prison slang at this time. then tu PAC wrote a line something like "they threw him in the 5-0", in one of his songs, at that point white kids & the general population started using it. the Hawaii 5 0 reference is cute but it didn't start the useage.

Answer 2

There used to be a TV show called Hawaii 50 (Five Oh). The fictional show was about the Hawaii State Police (50th State). Ironically, Hawaii does not HAVE a State Police force.