{
  "export": {
    "source": "https://urth.darkrealm.vip/thread/whorl/454",
    "note": "Exported from an unofficial mirror of a public mailing list. Copyright in each message remains with the person who wrote it.  Email addresses are obscured as `user at host`, the form the original archive published. This file was rebuilt from parsed fields rather than retained headers, so it is faithful in content but not byte-exact.",
    "addresses": "obscured as 'user at host'"
  },
  "archive": "whorl",
  "thread": {
    "id": 454,
    "subject": "Still more physics",
    "messages": 1,
    "voices": 1,
    "first": "1997-10-11T14:07:15+00:00",
    "last": "1997-10-11T14:07:15+00:00"
  },
  "messages": [
    {
      "message_id": "<whorl-v0007-0606@digest.urth.net>",
      "from": {
        "name": "John Eric Ivancich",
        "address": "ivancich at eecs.umich.edu"
      },
      "date": "1997-10-11T14:07:15+00:00",
      "subject": "(whorl) Still more physics",
      "in_reply_to": null,
      "reply_link": null,
      "blocks": [
        {
          "kind": "text",
          "depth": 0,
          "text": "Regarding mantis' (10/8/97) assertion that if the floater countered\nonly a portion the Whorl's rotational velocity, it would be that much\neasier for it to achieve non-standard heights...\n\nThat's a good point.  It's actually better than he suspected, though.\nSince\n\n        v*v\n    a = ---\n         r\n\nand since the outward force is proportional to the rate of\nacceleration (F=ma), if the velocity were to be reduced to half (and r\nwere held constant), the outward force would be 1/2*1/2, or 1/4th of\nthe normal force.  If you could counter three-fourths of the\nrotational velocity, then the outward force is only 1/16th of the\nnormal force!\n\nIn the scene [Calde, pp. 303-7**] where the floater does seem to\nfloat, there are two described effects:\n\n    1. Items (and people) in the floater seem to float.\n    2. The floater achieves an atypical height.\n\nIf the floater only counter-acted a portion of the Whorl's rotational\nvelocity, it might explain effect 2 but not effect 1.  \"Before Silk\nrecognized it, it had completed a leisurely quarter revolution,\nscarcely a span in front of his nose [Calde, p. 304**].\"  Things are\nactually floating, and not simply lighter than usual.\n\nThere are two possibilities for explaining effect 1.  Either the\nfloater completely counter-acted the Whorl's rotational velocity OR\nthe floater counter-acted part of it, then achieved a significant\nheight, and then started falling again back towards the surface (i.e.,\nlike the \"vomit comet\").\n\nThe second explanation doesn't seem likely, as they're floating for\nquite a period of time.  \"Silk's lungs filled and emptied before he\nrealized that the oars were the barrels of guns, and a half minute\ncrept by before he made out the blood-red triangle on its bottom\n[Calde p. 305**].\"  And quite a bit more conversations between the\ncharacters takes place during all this.\n\n\nWith respect to the reduced gravity-effect as one gets \"higher\", that\nis proportional to the distance from the center (no squares or such).\nSo those on a tower half way towards the center would weight half as\nmuch.\n\nDepending on the size of the Whorl and the size of the mountains\nseparating the cities, the mountains may not be so formidable.  The\ntroops might be able to leap 20 feet with each step as they approach\nthe top.  Maybe their leg muscles atrophy during the march.   :-)\n\n\nMantis says:"
        },
        {
          "kind": "quote",
          "depth": 1,
          "text": "Still, quite the apparant dilemna: the bigger the Whorl, the faster the\n\"groundspeed\"; the greater difficulty for the simulated gravity to be\novercome by a normal civilian ground vehicle."
        },
        {
          "kind": "text",
          "depth": 0,
          "text": "Indeed!\n\n\nEric\n\n\n** All page numbers referred to are from the mass paperback version\n   of TBotLS."
        }
      ]
    }
  ]
}