{ "correct_letter": "D", "correct_formula": "ΣF_ext = 0", "annotation": "Environment: g=9.81, F_drag=!=0", "choices": [ "ΣF_ext = m·g·tan(α_eq)", "PV = nRT", "G = m·g", "ΣF_ext = 0" ], "correct_index": 3, "physics_type": "AtRest", "seed": "AtRest|NewtonsFirstLaw/AtRest/0", "is_realworld": true, "dropped_wrong_formulas": [ "F_drag = (1/2)·C_d·ρ·A·v²" ] }