system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:If films are shot at 24fps, then why did we standardise 60 fps for monitors and tvs, a number that doesn't divide evenly into 24?
gpt
It has nothing to do with motion reproduction or the ease of converting it to television. If it was they would have picked some even multiple of 24- probably 48 or 72 frames a second so you could just transfer it directly without 3:2 pulldown (which causes unpleasant jerkiness during motions). On a film you can use whatever frame rate you want by just speeding up or slowing down the motor, with electronic television (and yes, there was a "mechanical television), you don't have that option. These days it would be ridiculously easy to put a crystal controlled clock in TVs and make it whatever you wanted, but back in the day with vacuum tubes they didn't have that option as a practical matter, so they synchronized the frame rate to the one thing that was easily available, the 60hz power line. If the mains frequency had been 48  or 72, or even 57 they would have used that rather than 60. 


TL;DR Mains electricity in the US is 60hz so TVs are too.