Free fall drop calculator API

Solves free fall under gravity (no drag) given a drop height or fall time, returning the other plus impact velocity in m/s and km/h, with optional initial velocity. Answers 'How long does it take to fall a given height?', 'What is the impact velocity from a drop?'.

Price$0.02per request

MethodPOST

Route/v1/engineering/free-fall

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

engineeringmechanicsphysicsfree-fallgravitydropimpact-velocitykinematics

API URLhttps://x402.hexl.dev/v1/engineering/free-fall

Integration docs

Example request

{
  "heightM": 20
}

Example response

{
  "heightM": 20,
  "timeS": 2.01962,
  "initialVelocityMs": 0,
  "gravityMs2": 9.80665,
  "impactVelocityMs": 19.805706,
  "impactVelocityKmh": 71.3005,
  "formula": "h = u*t + 0.5*g*t^2, v = u + g*t"
}

Input schema

{
  "type": "object",
  "required": [],
  "properties": {
    "heightM": {
      "type": "number",
      "description": "drop height (m)",
      "examples": [
        20
      ]
    },
    "timeS": {
      "type": "number",
      "description": "fall time (s); provide instead of height"
    },
    "initialVelocityMs": {
      "type": "number",
      "description": "initial downward velocity (m/s), default 0"
    },
    "gravity": {
      "type": "number",
      "description": "gravitational acceleration (m/s^2), default 9.80665"
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}