{
  "address": "1b95797bc16a435f1180a07101ef43c0",
  "category": "other",
  "question": "How fast is 100 km/h in mph?",
  "answer": "62.1371 mph",
  "askedBy": {
    "kind": "guest",
    "display": "method deck",
    "stamped": false,
    "id": null
  },
  "answeredBy": "method",
  "madeAt": "2026-09-30T22:39:30.722Z",
  "validUntil": null,
  "validityClass": "forever",
  "sources": [
    {
      "label": "Guide for the Use of the International System of Units (SI)",
      "url": null
    }
  ],
  "supersedes": null,
  "supersededBy": null,
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  "answerMethod": "method",
  "unsourced": false,
  "source": {
    "kind": "standard",
    "value": "NIST Special Publication 811 (2008 edition), Appendix B.8: mile = 1609.344 m, international nautical mile = 1852 m, foot = 0.3048 m, all exact; combined with the exact SI hour (3600 s) and second.",
    "retrieved_utc": "2026-09-30T19:29:48Z"
  },
  "qsha256": "2fb1b8a893a56066e64225ba9ad8ec154a2c75972b9a0e4d6e17d9aa7a8d63e1",
  "runOne": null,
  "cardContractVersion": "card_contract/1",
  "deck_id": "method-deck",
  "deck_title": "Method Deck",
  "method": {
    "name": "Speed conversion",
    "version": "1",
    "source_url_or_file": "methods/speed-conversion.cjs",
    "sha256_of_method_file": "bdbeb06afcbbff4bf6414839e30639e9b1e45edee12a14e3406e912cf51c2941"
  },
  "receipt": {
    "inSubstrate": false,
    "local": true,
    "modelCallsAtMint": 0,
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  },
  "method_deck": {
    "inputs": [
      {
        "name": "value",
        "type": "number",
        "unit": "from_unit",
        "required": true,
        "description": "The speed to convert"
      },
      {
        "name": "from_unit",
        "type": "string",
        "required": true,
        "description": "Unit of the input value",
        "enum": [
          "m_s",
          "km_h",
          "mph",
          "knot",
          "ft_s"
        ]
      },
      {
        "name": "to_unit",
        "type": "string",
        "required": true,
        "description": "Unit to convert into",
        "enum": [
          "m_s",
          "km_h",
          "mph",
          "knot",
          "ft_s"
        ]
      }
    ],
    "outputs": [
      {
        "name": "result",
        "unit": "to_unit",
        "description": "The converted speed"
      }
    ],
    "steps": [
      "Look up the exact meters-per-second equivalent of from_unit and of to_unit.",
      "Convert the input to m/s: mps = value * ms_per(from_unit).",
      "Convert m/s to the target unit: result = mps / ms_per(to_unit).",
      "Round result to 6 significant figures."
    ],
    "constants": [
      {
        "name": "m_s",
        "value": 1,
        "unit": "m/s",
        "source": 0
      },
      {
        "name": "km_h",
        "value": 0.2777777777777778,
        "unit": "m/s",
        "source": 0
      },
      {
        "name": "mph",
        "value": 0.44704,
        "unit": "m/s",
        "source": 0
      },
      {
        "name": "knot",
        "value": 0.5144444444444445,
        "unit": "m/s",
        "source": 0
      },
      {
        "name": "ft_s",
        "value": 0.3048,
        "unit": "m/s",
        "source": 0
      }
    ],
    "examples": [
      {
        "name": "worked example",
        "inputs": {
          "value": 100,
          "from_unit": "km_h",
          "to_unit": "mph"
        },
        "expected": {
          "answer": "62.1371 mph"
        },
        "check": "By hand: 100 km/h = 27.77778 m/s; 27.77778 / 0.44704 = 62.13712...; rounded to 6 significant figures is 62.1371."
      },
      {
        "name": "test vector: knot to km/h",
        "inputs": {
          "value": 1,
          "from_unit": "knot",
          "to_unit": "km_h"
        },
        "expected": {
          "answer": "1.85200 km/h"
        },
        "check": "By definition 1 knot = 1 nautical mile (1852 m) per hour = 1.852 km/h exactly."
      },
      {
        "name": "test vector: mph to ft/s",
        "inputs": {
          "value": 60,
          "from_unit": "mph",
          "to_unit": "ft_s"
        },
        "expected": {
          "answer": "88.0000 ft/s"
        },
        "check": "By hand: 60 mph = 60 * 0.44704 m/s = 26.8224 m/s; 26.8224 / 0.3048 = 88 exactly, matching the well-known 60 mph = 88 ft/s."
      }
    ],
    "disclaimer": null,
    "deck_category": "units"
  },
  "status": "minted",
  "kind": "method",
  "provenanceClass": "own_question",
  "provenance": {
    "schema": "card_provenance/2.0.0",
    "chain": [
      {
        "source": {
          "kind": "standard",
          "value": "NIST Special Publication 811 (2008 edition), Appendix B.8: mile = 1609.344 m, international nautical mile = 1852 m, foot = 0.3048 m, all exact; combined with the exact SI hour (3600 s) and second.",
          "retrieved_utc": "2026-09-30T19:29:48Z"
        },
        "sha256": "f76768cb40d2610110f30db9a652e697492a115b5141ee3674cedc2ae6146232",
        "supersedes": null,
        "added_utc": "2026-09-30T22:39:30.722Z",
        "added_by": "method:Speed conversion",
        "why": "the method that computed this answer",
        "check": null,
        "status_label": "pending",
        "signature": null
      }
    ]
  }
}