Quiz — travail et puissance.pdf

Question 1 sur 10 20:00

[{"id":96604,"question":"Quel est l'unité du travail dans le système international ?","option_a":"Newton (N)","option_b":"Joule (J)","option_c":"Watt (W)","option_d":"Pascal (Pa)","option_e":"","option_f":"","bonne_reponse":"b","explication":"Le travail s'exprime en joules (J), équivalent à un newton-mètre (N·m).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Newton (N)\", \"b\": \"Joule (J)\", \"c\": \"Watt (W)\", \"d\": \"Pascal (Pa)","_debug_options_count":4},{"id":96605,"question":"Un objet est déplacé horizontalement par une force constante. Si la force est perpendiculaire au déplacement, le travail est :","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"b","explication":"Le travail est nul car cos(90°) = 0 (W = F·d·cos(θ)).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":96606,"question":"La puissance mécanique se calcule par la formule :","option_a":"P = F·d","option_b":"P = W\/Δt","option_c":"P = m·g","option_d":"P = F·v","option_e":"","option_f":"","bonne_reponse":"b","explication":"La puissance est le travail divisé par le temps (P = W\/Δt) ou la force multipliée par la vitesse (P = F·v).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"P = F·d\", \"b\": \"P = W\/Δt\", \"c\": \"P = m·g\", \"d\": \"P = F·v\"}}","_debug_options_count":4},{"id":96607,"question":"Un ascenseur soulève une charge de 500 kg sur 10 m en 5 secondes. Quelle est la puissance développée (g = 10 N\/kg) ?","option_a":"1 000 W","option_b":"5 000 W","option_c":"10 000 W","option_d":"50 000 W","option_e":"","option_f":"","bonne_reponse":"b","explication":"Travail W = m·g·h = 500·10·10 = 5 000 J. Puissance P = W\/Δt = 5 000\/5 = 1 000 W.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"1 000 W\", \"b\": \"5 000 W\", \"c\": \"10 000 W\", \"d\": \"50 000 W\"}}","_debug_options_count":4},{"id":96608,"question":"Le travail du poids dépend du chemin parcouru.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"b","explication":"Le travail du poids est une force conservative : il ne dépend que des altitudes initiale et finale.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":96609,"question":"Quelle affirmation est correcte pour une force conservative ?","option_a":"Le travail dépend du chemin","option_b":"Le travail est nul","option_c":"Le travail ne dépend que des positions initiale et finale","option_d":"La force est toujours perpendiculaire au déplacement","option_e":"","option_f":"","bonne_reponse":"c","explication":"Une force conservative (comme le poids) a un travail indépendant du chemin parcouru.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"c\", \"options\": {\"a\": \"Le travail dépend du chemin\", \"b\": \"Le travail est nul\", \"c\": \"L","_debug_options_count":4},{"id":96610,"question":"Un moteur développe une puissance de 2 kW en soulevant une charge de 100 kg. Quelle est la vitesse de montée (g = 10 N\/kg) ?","option_a":"0,2 m\/s","option_b":"2 m\/s","option_c":"20 m\/s","option_d":"200 m\/s","option_e":"","option_f":"","bonne_reponse":"b","explication":"Puissance P = F·v → v = P\/F = 2000\/(100·10) = 2 m\/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\": \"0,2 m\/s\", \"b\": \"2 m\/s\", \"c\": \"20 m\/s\", \"d\": \"200 m\/s\"}}","_debug_options_count":4},{"id":96611,"question":"Le travail d'une force est toujours positif.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"b","explication":"Le travail peut être positif (force motrice), négatif (force résistante) ou nul (force perpendiculaire).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":96612,"question":"Quelle est la relation entre travail et énergie cinétique ?","option_a":"W = ΔEc","option_b":"W = Ec\/2","option_c":"W = m·v²","option_d":"W = F·a","option_e":"","option_f":"","bonne_reponse":"a","explication":"Le théorème de l'énergie cinétique stipule que le travail des forces extérieures est égal à la variation d'énergie cinétique (W = ΔEc).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"W = ΔEc\", \"b\": \"W = Ec\/2\", \"c\": \"W = m·v²\", \"d\": \"W = F·a\"}}","_debug_options_count":4},{"id":96613,"question":"Un skieur descend une pente sans frottements. Son énergie potentielle diminue. Que devient cette énergie ?","option_a":"Elle est perdue","option_b":"Elle se transforme en énergie cinétique","option_c":"Elle est stockée dans le skieur","option_d":"Elle est convertie en chaleur","option_e":"","option_f":"","bonne_reponse":"b","explication":"En l'absence de frottements, l'énergie potentielle se transforme intégralement en énergie cinétique (conservation de l'énergie mécanique).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Elle est perdue\", \"b\": \"Elle se transforme en énergie cinétique","_debug_options_count":4}]