Long Bar and the Speed of Light

[Appity]

I was asked this today, and I cannot picture an answer. Say you had a long bar in a vacuum, billions of miles long. If a force was applied lengthwise on one end, would the other end immediately respond? Would reference frames matter in this instance? I know information cannot travel faster than the speed of light, and I have a basic understanding of special relatively, but i cannot picture what would happen in this case...

 

[Fredrik]

There are lots of threads about this. Perhaps someone who participated in one of them can post a link.

The other end will not respond immediately. You will just create a mechanical wave that propagates at the speed of sound. (A longitudinal mechanical wave is, by definition, sound). If you hit it with a hammer that's moving faster than the speed of sound in that material, then you'll just break it and create a wave the propagates at the speed of sound.

 

[George Jones]

See

https://www.physicsforums.com/showthread.php?p=1856728#post1856728.