{
  "correct_letter": "A",
  "correct_formula": "y = h + x·tanθ - g·x² / (2·v_0²·cos²θ)",
  "annotation": "Environment: g=9.81, F_drag=!=0\nGround: e=0.5\nTennisBall: d = 0.07, e = 0.75, h = 0.95, v_0 = 1.57",
  "choices": [
    "y = h + x·tanθ - g·x² / (2·v_0²·cos²θ)",
    "λ = h/(m·v)",
    "h_next = e²·h_current",
    "y = h·cos(g·x / v_0²) + x·tanθ"
  ],
  "correct_index": 0,
  "physics_type": "Projectile",
  "seed": "Projectile|Gravity/Projectile/9",
  "is_realworld": true,
  "dropped_wrong_formulas": [
    "F_drag = (1/2)·C_d·ρ·A·v² (A = π·(d/2)²)"
  ]
}