{
  "correct_letter": "C",
  "correct_formula": "y(t) = h + v_0·t + (1/2)·g·t²",
  "annotation": "Environment: g=-9.8, F_drag=0.0\nGround: e = 0.4\nBronzeAntiqueSphere: d = 2.0, e = 0.45, h = 13.0, v_0 = 0.0\nAgingCopperSphere: d = 2.0, e = 0.5, h = 16.0, v_0 = 0.0",
  "choices": [
    "v_final = -e·v_impact",
    "F_fall = m·g·(1 + v/c) / √(1 - v²/c²)",
    "y(t) = h + v_0·t + (1/2)·g·t²",
    "n_1·sinθ_1 = n_2·sinθ_2"
  ],
  "correct_index": 2,
  "physics_type": "FreeFall",
  "seed": "FreeFall|benchmark/freefall/6"
}