[niccl]

I'd really like to see a citation for 25 Hz. It feels to me like a decimal point might be missing. And how does the knife moving at twice the frequency of the vegetables being cut work? do they do two complete cycles of the knife for every cut of the veges? that's not what I've seen watching cooking shows (which might not be the best thing to watch for this to be seen, of course)

[tempestn]

Hz vs kHz. Your parent's point is that the knife is vibrating far faster than even the fastest chefs would be slicing.

[oofbey]

25 chops per second would be EXTRAORDINARY. Possible? Probably but only with super elite training. Most competent home chefs can probably do 5 Hz and probably struggle to get to 10 Hz.

[mminer237]

The fastest button mashing record appears to be 16 Hz, so I definitely do not believe it is possible to chop with a knife in the double digits.

[scythe]

The sixteenth notes in "Crazy Train"[1] are nominally 552 per minute, or 9.2 Hz. Moving a knife at 10 Hz is probably very difficult. I would expect 2-3 Hz is a normal pace for a skilled knife user and 4-5 Hz is showing off.

1: https://youtube.com/watch?v=tMDFv5m18Pw#t=0m32s