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What is the fastest tangential velocity, that was reached by a man-made object? I have only found examples of angular velocity.

More specifically, I am looking for the speed of the rim of spinning objects, not ions in an accelerator or satellites in an orbit

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    $\begingroup$ Depends on what your definition of "manmade" is. Does a lead atom that we ionized and put in an accelerator count? Because then the answer is basically "the speed of light." $\endgroup$
    – probably_someone
    Commented Oct 22, 2018 at 15:22
  • $\begingroup$ This may be of interest to you: businessinsider.com/fastest-object-robert-brownlee-2016-2 $\endgroup$
    – roshoka
    Commented Oct 22, 2018 at 16:10
  • $\begingroup$ @probably_someone Thanks for your comment, I edited the question to be more specific $\endgroup$
    – mario
    Commented Oct 22, 2018 at 16:10

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For any material with density $\rho$ and ultimate tensile strength $\sigma$, the fastest tangential speed $v$ a disk or hoop (any cylindrically symmetric object) made of that material can achieve at its rim before flying apart is $$v=\sqrt{\frac{\sigma}{\rho}}.$$ For carbon fiber, with $\rho=2000~ \mathrm{kg/m^3}$ and $\sigma = 3.5~ \mathrm{GPa}$, you get $v \approx 1300~ \mathrm{m/s}$. So the surprising (to me at least) result is that with ordinary materials, the fastest you can possibly spin a disk is no faster than a rifle bullet.

With carbon nanotubes, which may be an order of magnitude stronger, you might approach 5 km/s.

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  • $\begingroup$ Interesting result! It's also interesting that the result seems to be independent of the shape and the diameter of the object $\endgroup$
    – mario
    Commented Oct 22, 2018 at 21:41
  • $\begingroup$ Yeah, the first time I ran across the fact that it’s independent of size was in an engineering handbook in the context of lathe chucks, and I thought it must be a mistake. But the change in radius and the change in radial acceleration cancel each other out. $\endgroup$
    – Ben51
    Commented Oct 23, 2018 at 0:23

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