• sarchar
    link
    fedilink
    English
    arrow-up
    7
    ·
    9 months ago

    This begs the question for me - at terminal falling speed, what’s the fastest you can decelerate to 0 and not sustain injury? And given that, how much more distance would you need to move?

    Maybe a superhero can catch you, decelerate you to 0 over 3 inches and that’s good enough?

    • birbs@lemmy.world
      link
      fedilink
      arrow-up
      7
      ·
      edit-2
      9 months ago

      Human terminal velocity is roughly 56 m/s. Let’s say our superhero wants to decelerate the person at 10G, which should be survivable for a short period. That would be 0.6 seconds of deceleration over 48 m. That’s a short time but quite a long distance, let’s slow down faster:

      20G -> 0.28 seconds, 24 m.

      30G -> 0.19 seconds, 16 m.

      50G -> 0.11 seconds, 9.6 m.

      100G -> 0.057 seconds, 4.79 m.

      200G -> 0.029 seconds, 2.45 m.

      5000G -> 0.0011 seconds, 3.6 inches.

      A 40 mph car crash in a modern car into a solid wall gives around 15G.

      F1 driver David Purley survived a 180G crash in 1977.

      In short, I don’t recommend catching someone with 3 inches to spare.

      • Toine@sh.itjust.works
        link
        fedilink
        arrow-up
        2
        ·
        9 months ago

        Something is wrong with your distance formula by a factor of 4 (you should have D=1/2 * V_0^2 / a) . Not that it changes anything in your conclusions.