Quiz — série corrigé cinématique.pdf

Question 1 sur 10 20:00

[{"id":75468,"question":"Un mobile se déplace à vitesse constante de 10 m\/s pendant 5 secondes. Quelle distance parcourt-il ?","option_a":"2 m","option_b":"15 m","option_c":"50 m","option_d":"100 m","option_e":"","option_f":"","bonne_reponse":"c","explication":"Dans un MRU, la distance parcourue se calcule avec la formule d = v × t. Ici, d = 10 m\/s × 5 s = 50 m.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"c\", \"options\": {\"a\": \"2 m\", \"b\": \"15 m\", \"c\": \"50 m\", \"d\": \"100 m\"}}","_debug_options_count":4},{"id":75469,"question":"Un objet en chute libre a une accélération de 9,8 m\/s². Cette affirmation est-elle vraie ?","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"L’accélération de la chute libre est bien égale à l’accélération de la pesanteur, g = 9,8 m\/s² (en négligeant les frottements).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":75470,"question":"Dans un MRUA, si l’accélération est nulle, le mouvement est :","option_a":"Rectiligne uniforme","option_b":"Uniformément accéléré","option_c":"Circulaire","option_d":"Décéléré","option_e":"","option_f":"","bonne_reponse":"a","explication":"Si l’accélération est nulle, la vitesse est constante : le mouvement est donc rectiligne uniforme (MRU).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Rectiligne uniforme\", \"b\": \"Uniformément accéléré\", \"c\": \"Cir","_debug_options_count":4},{"id":75471,"question":"Un véhicule accélère de 0 à 30 m\/s en 10 secondes. Quelle est son accélération moyenne ?","option_a":"0,3 m\/s²","option_b":"3 m\/s²","option_c":"30 m\/s²","option_d":"300 m\/s²","option_e":"","option_f":"","bonne_reponse":"b","explication":"L’accélération moyenne se calcule avec a = (v_f - v_i) \/ t = (30 - 0) \/ 10 = 3 m\/s².","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"0,3 m\/s²\", \"b\": \"3 m\/s²\", \"c\": \"30 m\/s²\", \"d\": \"300 m\/s²\"}}","_debug_options_count":4},{"id":75472,"question":"Un corps lancé verticalement vers le haut retombe au même point. Son mouvement est symétrique.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Le mouvement de montée et de descente est symétrique : le temps de montée est égal au temps de descente, et les vitesses sont opposées.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":75473,"question":"Quelle formule relie la vitesse finale (v_f), la vitesse initiale (v_i), l’accélération (a) et le temps (t) dans un MRUA ?","option_a":"v_f = v_i + a × t","option_b":"v_f = v_i × t + a","option_c":"v_f = v_i + a \/ t","option_d":"v_f = (v_i + v_f) \/ 2 × t","option_e":"","option_f":"","bonne_reponse":"a","explication":"La formule correcte est v_f = v_i + a × t, issue de la définition de l’accélération.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"v_f = v_i + a × t\", \"b\": \"v_f = v_i × t + a\", \"c\": \"v_f = v_i +","_debug_options_count":4},{"id":75474,"question":"Un satellite en orbite circulaire autour de la Terre a une vitesse constante. Son accélération est :","option_a":"Nulle","option_b":"Centripète","option_c":"Tangentielle","option_d":"Négative","option_e":"","option_f":"","bonne_reponse":"b","explication":"Même si la vitesse est constante en valeur, sa direction change : l’accélération est donc centripète (dirigée vers le centre de l’orbite).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Nulle\", \"b\": \"Centripète\", \"c\": \"Tangentielle\", \"d\": \"Négative\"","_debug_options_count":4},{"id":75475,"question":"Un objet tombe d’une hauteur de 20 m. Quel est son temps de chute (g = 10 m\/s²) ?","option_a":"1 s","option_b":"2 s","option_c":"4 s","option_d":"8 s","option_e":"","option_f":"","bonne_reponse":"b","explication":"En chute libre, la hauteur h = ½ g t². Donc t = √(2h\/g) = √(40\/10) = 2 s.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"1 s\", \"b\": \"2 s\", \"c\": \"4 s\", \"d\": \"8 s\"}}","_debug_options_count":4},{"id":75476,"question":"Dans un mouvement circulaire uniforme, l’accélération est toujours dirigée vers le centre de la trajectoire.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"L’accélération centripète est toujours dirigée vers le centre de la trajectoire dans un mouvement circulaire uniforme.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":75477,"question":"Un mobile part du repos (v_i = 0) et accélère à 2 m\/s² pendant 3 secondes. Quelle est sa vitesse finale ?","option_a":"2 m\/s","option_b":"3 m\/s","option_c":"6 m\/s","option_d":"12 m\/s","option_e":"","option_f":"","bonne_reponse":"c","explication":"Avec v_f = v_i + a × t = 0 + 2 × 3 = 6 m\/s.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"c\", \"options\": {\"a\": \"2 m\/s\", \"b\": \"3 m\/s\", \"c\": \"6 m\/s\", \"d\": \"12 m\/s\"}}","_debug_options_count":4}]