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.
Glass cracks propagate at an absurdly fast rate. Something like 4x the speed of sound (1400m/s). Not a physical thing moving, but very common.
I think it would propagate at the speed of sound in glass.
It seems that depending on the type of glass and the direction of the waves (longitudinal, shear, or Extensional) the speed of sound in glass can be between 2300-6000 m/s
Longitudinal is the type we normally think of though, and that is between 3900-5600 m/s. Which is still much more variation than I was expecting.
The speed of sound in air is around 340 m/s depending on temperature.
So if the op is correct about the speed, then it seems the cracks propagate slower than the speed of sound in glass.
https://www.engineeringtoolbox.com/sound-speed-solids-d_713.html
Interesting… how do you know about this?
Slow Mo Guys on YouTube have filmed glass cracking and calculated its speed many times. Very lovely channel that I recommend!
OP specifically asked for something with mass. This is not a thing with mass. This is the same as saying a shadow can move faster than the speed of light.
breaks a pane of glass over your head
let me see you do that with a shadow
Haha
Not the same thing, since the movement of a shadow from point A to point B does not cause any transfer of energy or information between those points, whereas the shattering of glass can be initiated from point A and travel to point B at the given speed, transferring information (and possibly energy) between them.
As for not being a moving object, that’s fair, and why they mentioned it’s not quite the same thing in their comment.