{
  "correct_letter": "D",
  "correct_formula": "F_N - m·g·cosθ = m·v²/R",
  "annotation": "Environment: g=-9.81, F_drag=0.0\nGround: mu_s=0.0, mu_k=0.0\nTireSphere: d = 1.0, e = 0.6, theta_start = 0°, v_0 = 10.0\nTrack_0: R = 2.0, e = 0.3, theta_min = 0°, theta_max = 360°, mu_s = 0.0, mu_k = 0.0",
  "choices": [
    "ω = √(g·cosθ / R) · (1 + sinθ)",
    "e = (v_2f - v_1f) / (v_1i - v_2i)",
    "Q = m·c·ΔT",
    "F_N - m·g·cosθ = m·v²/R"
  ],
  "correct_index": 3,
  "physics_type": "Circular",
  "seed": "Circular|benchmark/circular_newbatch/5"
}