{"id":1578,"date":"2026-09-08T08:07:48","date_gmt":"2026-09-08T08:07:48","guid":{"rendered":"https:\/\/maroczain.com\/scolaire.maroczain.com\/?page_id=1578"},"modified":"2026-09-08T08:07:48","modified_gmt":"2026-09-08T08:07:48","slug":"dynamique-newtonienne-cpge","status":"publish","type":"page","link":"https:\/\/maroczain.com\/scolaire.maroczain.com\/dynamique-newtonienne-cpge\/","title":{"rendered":"Dynamique Newtonienne CPGE."},"content":{"rendered":"\n&#8220;`html\n<div id=\"mza-dynamique-cpge\">\n\n<style>\n#mza-dynamique-cpge,#mza-dynamique-cpge *{box-sizing:border-box}\n#mza-dynamique-cpge{\n --navy:#06172c;--navy2:#0d416d;--gold:#c99a36;--gold2:#efd68c;\n --paper:#f5f6f8;--white:#fff;--text:#18283a;--muted:#687789;--line:#dfe5eb;\n font-family:Arial,Helvetica,sans-serif;background:var(--paper);color:var(--text);overflow:hidden\n}\n#mza-dynamique-cpge a{text-decoration:none;color:inherit}\n#mza-dynamique-cpge .wrap{max-width:1200px;margin:auto;padding:0 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var(--line);border-radius:18px;padding:22px;margin-bottom:14px\n}\n#mza-dynamique-cpge .exercise h3{color:var(--navy);margin:0 0 10px}\n#mza-dynamique-cpge .level{\n display:inline-block;padding:6px 9px;margin-bottom:10px;border-radius:999px;\n background:#f1eee5;color:#7b5b1d;font-size:10px;font-weight:900\n}\n#mza-dynamique-cpge .exercise p{color:var(--muted);line-height:1.7}\n#mza-dynamique-cpge .hint{\n display:none;margin-top:12px;padding:15px;border-radius:12px;\n background:#eef3f7;color:#425469;line-height:1.65\n}\n#mza-dynamique-cpge .qcm{\n background:#fff;border:1px solid var(--line);border-radius:23px;padding:28px\n}\n#mza-dynamique-cpge .question{\n padding:20px;margin:15px 0;background:#f7f8fa;border-radius:14px\n}\n#mza-dynamique-cpge .question strong{display:block;color:var(--navy);margin-bottom:12px}\n#mza-dynamique-cpge label{display:block;padding:8px 0;color:#526174;cursor:pointer}\n#mza-dynamique-cpge #dynResult{\n display:none;margin-top:18px;padding:20px;border-radius:14px;background:var(--navy);color:#fff\n}\n#mza-dynamique-cpge .cta{\n text-align:center;padding:50px 24px;border-radius:25px;\n background:linear-gradient(135deg,#06172c,#0d416d);color:#fff\n}\n#mza-dynamique-cpge .cta h2{color:#fff}\n#mza-dynamique-cpge .cta p{max-width:760px;margin:0 auto 22px;color:#cfdae4;line-height:1.7}\n\n@media(max-width:900px){\n #mza-dynamique-cpge .grid,\n #mza-dynamique-cpge .grid3,\n #mza-dynamique-cpge .method{grid-template-columns:1fr}\n}\n<\/style>\n\n<header class=\"hero\">\n<div class=\"wrap\">\n\n<span class=\"badge\">COURS 03 \u2022 PHYSIQUE CPGE<\/span>\n\n<h1>Isoler.<br>Projeter. R\u00e9soudre.<\/h1>\n\n<p class=\"lead\">\nLa dynamique relie le mouvement aux interactions responsables de son \u00e9volution.\nLe c\u0153ur de la m\u00e9thode consiste \u00e0 choisir le syst\u00e8me, recenser les forces,\nappliquer la deuxi\u00e8me loi de Newton puis projeter intelligemment.\n<\/p>\n\n<div class=\"actions\">\n<a href=\"#cours\" class=\"btn gold\">\ud83d\udcda COMMENCER<\/a>\n<a href=\"#methode\" class=\"btn glass\">\ud83e\udde0 M\u00c9THODE<\/a>\n<a href=\"#exercices\" class=\"btn glass\">\ud83e\udde9 EXERCICES<\/a>\n<a href=\"#qcm\" class=\"btn glass\">\u2753 QCM<\/a>\n<\/div>\n\n<\/div>\n<\/header>\n\n<section id=\"cours\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">1. SYST\u00c8ME M\u00c9CANIQUE<\/span>\n<h2>Avant toute \u00e9quation : choisir ce que l&#8217;on \u00e9tudie.<\/h2>\n<\/div>\n\n<div class=\"grid\">\n\n<div class=\"card\">\n<h3>Point mat\u00e9riel<\/h3>\n<p>\nOn mod\u00e9lise l&#8217;objet par un point portant sa masse lorsque sa taille et sa rotation\nne jouent pas de r\u00f4le dans le probl\u00e8me.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Syst\u00e8me<\/h3>\n<p>\nLe syst\u00e8me peut \u00eatre un objet, plusieurs objets, un solide ou un ensemble de corps.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Interactions ext\u00e9rieures<\/h3>\n<p>\nSeules les actions exerc\u00e9es par l&#8217;ext\u00e9rieur sur le syst\u00e8me interviennent dans le bilan des forces.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>R\u00e9flexe CPGE<\/h3>\n<p>\n\u00c9crire explicitement : \u00ab syst\u00e8me \u00e9tudi\u00e9 \u00bb, \u00ab r\u00e9f\u00e9rentiel \u00bb, \u00ab rep\u00e8re \u00bb.\n<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">2. R\u00c9F\u00c9RENTIEL GALIL\u00c9EN<\/span>\n<h2>Le cadre naturel des lois de Newton.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nLes lois de Newton s&#8217;\u00e9crivent sous leur forme simple dans un r\u00e9f\u00e9rentiel galil\u00e9en.\n<\/p>\n\n<div class=\"tip\">\n\u00c0 l&#8217;\u00e9chelle d&#8217;exp\u00e9riences courantes de courte dur\u00e9e, le r\u00e9f\u00e9rentiel terrestre peut souvent \u00eatre assimil\u00e9 \u00e0 un r\u00e9f\u00e9rentiel galil\u00e9en.\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">3. PREMI\u00c8RE LOI DE NEWTON<\/span>\n<h2>Principe d&#8217;inertie.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<div class=\"formula\">\n\u03a3F<sub>ext<\/sub> = 0\n<\/div>\n\n<p>implique, dans un r\u00e9f\u00e9rentiel galil\u00e9en :<\/p>\n\n<div class=\"formula\">\nv = constante\n<\/div>\n\n<p>\nL&#8217;immobilit\u00e9 n&#8217;est qu&#8217;un cas particulier du mouvement rectiligne uniforme.\n<\/p>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">4. DEUXI\u00c8ME LOI DE NEWTON<\/span>\n<h2>La relation fondamentale de la dynamique.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<div class=\"formula\">\n\u03a3F<sub>ext<\/sub> = d p \/ dt\n<\/div>\n\n<p>\navec :\n<\/p>\n\n<div class=\"formula\">\np = mv\n<\/div>\n\n<p>\nSi la masse est constante :\n<\/p>\n\n<div class=\"formula\">\n\u03a3F<sub>ext<\/sub> = ma\n<\/div>\n\n<\/div>\n\n<div class=\"tip\">\nLa forme \u03a3F=ma est un cas particulier de la loi g\u00e9n\u00e9rale portant sur la quantit\u00e9 de mouvement.\n<\/div>\n\n<\/div>\n<\/section>\n\n<section id=\"methode\" class=\"dark\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\" style=\"color:#efd68c\">MZA NEWTON ENGINE<\/span>\n<h2>La proc\u00e9dure universelle.<\/h2>\n<\/div>\n\n<div class=\"method\">\n<div><b>01<\/b><span>SYST\u00c8ME<\/span><\/div>\n<div><b>02<\/b><span>R\u00c9F\u00c9RENTIEL<\/span><\/div>\n<div><b>03<\/b><span>BILAN DES FORCES<\/span><\/div>\n<div><b>04<\/b><span>NEWTON<\/span><\/div>\n<div><b>05<\/b><span>PROJECTION<\/span><\/div>\n<div><b>06<\/b><span>INTERPR\u00c9TATION<\/span><\/div>\n<\/div>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">5. POIDS<\/span>\n<h2>L&#8217;action gravitationnelle terrestre.<\/h2>\n<\/div>\n\n<div class=\"grid\">\n\n<div class=\"card\">\n<h3>Expression<\/h3>\n\n<div class=\"formula\">\nP = mg\n<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>Direction<\/h3>\n<p>\nVerticale, dirig\u00e9e vers le centre de la Terre.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Norme<\/h3>\n\n<div class=\"formula\">\nP = mg\n<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>Attention<\/h3>\n<p>\nLa masse s&#8217;exprime en kilogrammes. Le poids est une force exprim\u00e9e en newtons.\n<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">6. R\u00c9ACTION D&#8217;UN SUPPORT<\/span>\n<h2>Normale et frottement.<\/h2>\n<\/div>\n\n<div class=\"grid\">\n\n<div class=\"card\">\n<h3>R\u00e9action normale<\/h3>\n\n<p>\nLa composante normale N est perpendiculaire au support.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Frottement<\/h3>\n\n<p>\nLa composante tangentielle s&#8217;oppose g\u00e9n\u00e9ralement au mouvement ou \u00e0 la tendance au glissement.\n<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Mod\u00e8le de Coulomb<\/h3>\n\n<div class=\"formula\">\n|f| \u2264 \u03bc<sub>s<\/sub>N\n<\/div>\n\n<p>en adh\u00e9rence.<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Glissement<\/h3>\n\n<div class=\"formula\">\n|f| = \u03bc<sub>d<\/sub>N\n<\/div>\n\n<p>dans un mod\u00e8le simplifi\u00e9 de frottement dynamique.<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">7. TENSION D&#8217;UN FIL<\/span>\n<h2>Une force dirig\u00e9e selon le fil.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un fil id\u00e9al, suppos\u00e9 sans masse et inextensible,\nla tension est dirig\u00e9e le long du fil.\n<\/p>\n\n<div class=\"formula\">\nT = T u\n<\/div>\n\n<p>\nLa direction d\u00e9pend de la g\u00e9om\u00e9trie du probl\u00e8me.\n<\/p>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">8. RESSORT<\/span>\n<h2>Force de rappel.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un ressort id\u00e9al :\n<\/p>\n\n<div class=\"formula\">\nF = -k x\n<\/div>\n\n<p>\no\u00f9 x mesure l&#8217;allongement alg\u00e9brique par rapport \u00e0 la position d&#8217;\u00e9quilibre.\n<\/p>\n\n<div class=\"tip\">\nLe signe \u00ab &#8211; \u00bb exprime que la force est dirig\u00e9e vers la position d&#8217;\u00e9quilibre.\n<\/div>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">9. PLAN INCLIN\u00c9<\/span>\n<h2>Choisir les bons axes simplifie tout.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un bloc sur un plan inclin\u00e9 d&#8217;angle \u03b1, il est souvent judicieux de choisir :\n<\/p>\n\n<ul>\n<li>un axe tangent au plan ;<\/li>\n<li>un axe normal au plan.<\/li>\n<\/ul>\n\n<p>\nLe poids se d\u00e9compose alors en :\n<\/p>\n\n<div class=\"formula\">\nP<sub>t<\/sub> = mg sin \u03b1\n<\/div>\n\n<div class=\"formula\">\nP<sub>n<\/sub> = mg cos \u03b1\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">10. MOUVEMENT CIRCULAIRE<\/span>\n<h2>La force radiale ne dispara\u00eet jamais.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nPour un mouvement circulaire uniforme de rayon R et de vitesse v :\n<\/p>\n\n<div class=\"formula\">\na<sub>r<\/sub> = v\u00b2\/R\n<\/div>\n\n<p>\ndirig\u00e9e vers le centre.\n<\/p>\n\n<div class=\"formula\">\n\u03a3F<sub>radial<\/sub> = mv\u00b2\/R\n<\/div>\n\n<div class=\"tip\">\n\u00ab Force centrip\u00e8te \u00bb n&#8217;est pas une force suppl\u00e9mentaire : c&#8217;est le nom donn\u00e9 \u00e0 la r\u00e9sultante radiale n\u00e9cessaire au mouvement circulaire.\n<\/div>\n\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">11. TROISI\u00c8ME LOI DE NEWTON<\/span>\n<h2>Action et r\u00e9action.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<p>\nSi A exerce une force sur B, alors B exerce sur A une force oppos\u00e9e :\n<\/p>\n\n<div class=\"formula\">\nF<sub>A\u2192B<\/sub> = -F<sub>B\u2192A<\/sub>\n<\/div>\n\n<div class=\"tip\">\nLes deux forces s&#8217;exercent sur deux syst\u00e8mes diff\u00e9rents. Elles ne s&#8217;annulent donc pas dans le bilan d&#8217;un seul objet.\n<\/div>\n\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">12. QUANTIT\u00c9 DE MOUVEMENT<\/span>\n<h2>Une grandeur fondamentale pour les syst\u00e8mes.<\/h2>\n<\/div>\n\n<div class=\"grid\">\n\n<div class=\"card\">\n<h3>D\u00e9finition<\/h3>\n\n<div class=\"formula\">\np = mv\n<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>Th\u00e9or\u00e8me<\/h3>\n\n<div class=\"formula\">\ndp\/dt = \u03a3F<sub>ext<\/sub>\n<\/div>\n<\/div>\n\n<div class=\"card\">\n<h3>Syst\u00e8me isol\u00e9<\/h3>\n\n<div class=\"formula\">\n\u03a3F<sub>ext<\/sub> = 0\n<\/div>\n\n<p>donc p est constante.<\/p>\n<\/div>\n\n<div class=\"card\">\n<h3>Applications<\/h3>\n<p>\nCollisions, recul, propulsion et syst\u00e8mes \u00e0 plusieurs corps.\n<\/p>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section id=\"exercices\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">13. EXERCICES PROGRESSIFS<\/span>\n<h2>Apprendre \u00e0 construire le bilan des forces.<\/h2>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU 1<\/span>\n\n<h3>Exercice 1 \u2014 Chute libre<\/h3>\n\n<p>\nUn objet de masse m est l\u00e2ch\u00e9 sans vitesse initiale, en n\u00e9gligeant les frottements de l&#8217;air.\n\u00c9tablir son \u00e9quation de mouvement.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaDynHint('dynHint1')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"dynHint1\" class=\"hint\">\nLe seul effort ext\u00e9rieur est le poids. Choisissez un axe vertical avant d&#8217;\u00e9crire les signes.\n<\/div>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU 2<\/span>\n\n<h3>Exercice 2 \u2014 Plan inclin\u00e9 sans frottement<\/h3>\n\n<p>\nUn bloc glisse sur un plan d&#8217;angle \u03b1 sans frottement.\nD\u00e9terminer son acc\u00e9l\u00e9ration tangentielle.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaDynHint('dynHint2')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"dynHint2\" class=\"hint\">\nProjetez la deuxi\u00e8me loi de Newton selon l&#8217;axe parall\u00e8le au plan.\n<\/div>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU 3<\/span>\n\n<h3>Exercice 3 \u2014 Plan inclin\u00e9 avec frottement<\/h3>\n\n<p>\nUn bloc descend sur un plan inclin\u00e9 avec un coefficient de frottement dynamique \u03bc.\nD\u00e9terminer l&#8217;acc\u00e9l\u00e9ration.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaDynHint('dynHint3')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"dynHint3\" class=\"hint\">\nD\u00e9terminez d&#8217;abord la r\u00e9action normale, puis l&#8217;intensit\u00e9 du frottement.\n<\/div>\n<\/div>\n\n<div class=\"exercise\">\n<span class=\"level\">NIVEAU PR\u00c9PA<\/span>\n\n<h3>Exercice 4 \u2014 Deux masses et poulie<\/h3>\n\n<p>\nDeux masses m\u2081 et m\u2082 sont reli\u00e9es par un fil id\u00e9al passant sur une poulie id\u00e9ale.\nD\u00e9terminer l&#8217;acc\u00e9l\u00e9ration du syst\u00e8me et la tension du fil.\n<\/p>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaDynHint('dynHint4')\">\ud83d\udca1 INDICE<\/button>\n\n<div id=\"dynHint4\" class=\"hint\">\n\u00c9crivez une \u00e9quation de Newton pour chaque masse puis utilisez la contrainte cin\u00e9matique impos\u00e9e par le fil.\n<\/div>\n<\/div>\n\n<\/div>\n<\/section>\n\n<section style=\"background:#efede7\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">14. PROBLEM LAB<\/span>\n<h2>Mission : voiture dans un virage.<\/h2>\n<\/div>\n\n<div class=\"card\">\n\n<h3>Situation<\/h3>\n\n<p>\nUne voiture de masse m d\u00e9crit un virage horizontal de rayon R \u00e0 vitesse constante v.\nOn suppose que l&#8217;adh\u00e9rence pneu-route fournit la force n\u00e9cessaire au mouvement circulaire.\n<\/p>\n\n<p>Votre mission :<\/p>\n\n<ol>\n<li>choisir le syst\u00e8me ;<\/li>\n<li>faire le bilan des forces ;<\/li>\n<li>identifier la direction de l&#8217;acc\u00e9l\u00e9ration ;<\/li>\n<li>projeter verticalement ;<\/li>\n<li>projeter radialement ;<\/li>\n<li>d\u00e9terminer la force de frottement n\u00e9cessaire ;<\/li>\n<li>utiliser la condition |f| \u2264 \u03bcN ;<\/li>\n<li>d\u00e9duire une vitesse maximale compatible avec l&#8217;adh\u00e9rence ;<\/li>\n<li>interpr\u00e9ter l&#8217;influence du rayon R et de \u03bc.<\/li>\n<\/ol>\n\n<div class=\"actions\">\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaDynHint('dynMission1')\">\ud83d\udca1 INDICE<\/button>\n<button type=\"button\" class=\"btn\" style=\"background:#06172c;color:#fff\" onclick=\"mzaDynHint('dynMission2')\">\ud83e\udde0 M\u00c9THODE<\/button>\n<\/div>\n\n<div id=\"dynMission1\" class=\"hint\">\nVerticalement, l&#8217;acc\u00e9l\u00e9ration est nulle. Radialement, elle vaut v\u00b2\/R vers le centre.\n<\/div>\n\n<div id=\"dynMission2\" class=\"hint\">\nLa force de frottement statique est ici horizontale et fournit la r\u00e9sultante centrip\u00e8te. Elle n&#8217;est pas forc\u00e9ment \u00e9gale \u00e0 \u03bcN : \u03bcN est sa valeur maximale admissible.\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section class=\"dark\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\" style=\"color:#efd68c\">MZA FORCE CHECK<\/span>\n<h2>Avant de valider une \u00e9quation de dynamique.<\/h2>\n<\/div>\n\n<div class=\"method\">\n<div><b>A<\/b><span>SYST\u00c8ME<\/span><\/div>\n<div><b>B<\/b><span>FORCES<\/span><\/div>\n<div><b>C<\/b><span>AXES<\/span><\/div>\n<div><b>D<\/b><span>NEWTON<\/span><\/div>\n<div><b>E<\/b><span>PROJECTIONS<\/span><\/div>\n<div><b>F<\/b><span>SENS PHYSIQUE<\/span><\/div>\n<\/div>\n\n<\/div>\n<\/section>\n\n<section id=\"qcm\">\n<div class=\"wrap\">\n\n<div class=\"head\">\n<span class=\"kicker\">15. QCM DE VALIDATION<\/span>\n<h2>Diagnostic Dynamique Newtonienne.<\/h2>\n\n<p>Le score est affich\u00e9 sans r\u00e9v\u00e9ler les r\u00e9ponses correctes.<\/p>\n<\/div>\n\n<div class=\"qcm\">\n\n<form id=\"dynQuiz\">\n\n<div class=\"question\">\n<strong>1. Pour une masse constante, la deuxi\u00e8me loi de Newton s&#8217;\u00e9crit :<\/strong>\n<label><input type=\"radio\" name=\"n1\" value=\"1\"> \u03a3F = ma<\/label>\n<label><input type=\"radio\" name=\"n1\" value=\"0\"> \u03a3F = mv<\/label>\n<label><input type=\"radio\" name=\"n1\" value=\"0\"> \u03a3F = m\/v<\/label>\n<label><input type=\"radio\" name=\"n1\" value=\"0\"> \u03a3F = 0 toujours<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>2. La r\u00e9action normale d&#8217;un support est :<\/strong>\n<label><input type=\"radio\" name=\"n2\" value=\"1\"> perpendiculaire au support<\/label>\n<label><input type=\"radio\" name=\"n2\" value=\"0\"> toujours parall\u00e8le au mouvement<\/label>\n<label><input type=\"radio\" name=\"n2\" value=\"0\"> toujours \u00e9gale au poids<\/label>\n<label><input type=\"radio\" name=\"n2\" value=\"0\"> ind\u00e9pendante du contact<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>3. Deux forces d&#8217;action-r\u00e9action :<\/strong>\n<label><input type=\"radio\" name=\"n3\" value=\"1\"> s&#8217;exercent sur deux syst\u00e8mes diff\u00e9rents<\/label>\n<label><input type=\"radio\" name=\"n3\" value=\"0\"> s&#8217;annulent toujours sur le m\u00eame objet<\/label>\n<label><input type=\"radio\" name=\"n3\" value=\"0\"> ont toujours la m\u00eame direction et le m\u00eame sens<\/label>\n<label><input type=\"radio\" name=\"n3\" value=\"0\"> n&#8217;existent qu&#8217;en statique<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>4. Dans un mouvement circulaire uniforme :<\/strong>\n<label><input type=\"radio\" name=\"n4\" value=\"1\"> l&#8217;acc\u00e9l\u00e9ration est dirig\u00e9e vers le centre<\/label>\n<label><input type=\"radio\" name=\"n4\" value=\"0\"> l&#8217;acc\u00e9l\u00e9ration est nulle<\/label>\n<label><input type=\"radio\" name=\"n4\" value=\"0\"> aucune force n&#8217;agit<\/label>\n<label><input type=\"radio\" name=\"n4\" value=\"0\"> la vitesse vectorielle est constante<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>5. Pour un ressort id\u00e9al :<\/strong>\n<label><input type=\"radio\" name=\"n5\" value=\"1\"> la force s&#8217;oppose \u00e0 l&#8217;allongement<\/label>\n<label><input type=\"radio\" name=\"n5\" value=\"0\"> la force est toujours dirig\u00e9e vers l&#8217;ext\u00e9rieur<\/label>\n<label><input type=\"radio\" name=\"n5\" value=\"0\"> la force est ind\u00e9pendante de l&#8217;allongement<\/label>\n<label><input type=\"radio\" name=\"n5\" value=\"0\"> la force vaut mg<\/label>\n<\/div>\n\n<div class=\"question\">\n<strong>6. Si la r\u00e9sultante des forces ext\u00e9rieures est nulle dans un r\u00e9f\u00e9rentiel galil\u00e9en :<\/strong>\n<label><input type=\"radio\" name=\"n6\" value=\"1\"> la quantit\u00e9 de mouvement est constante<\/label>\n<label><input type=\"radio\" name=\"n6\" value=\"0\"> la vitesse est n\u00e9cessairement nulle<\/label>\n<label><input type=\"radio\" name=\"n6\" value=\"0\"> l&#8217;acc\u00e9l\u00e9ration est infinie<\/label>\n<label><input type=\"radio\" name=\"n6\" value=\"0\"> le poids dispara\u00eet<\/label>\n<\/div>\n\n<button type=\"button\" class=\"btn gold\" onclick=\"mzaDynScore()\">\nVALIDER MON QCM\n<\/button>\n\n<\/form>\n\n<div id=\"dynResult\"><\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<section>\n<div class=\"wrap\">\n\n<div class=\"cta\">\n\n<div style=\"font-size:43px\">\u03a3F = ma<\/div>\n\n<h2>Une bonne dynamique commence par un bon bilan des forces.<\/h2>\n\n<p>\nSyst\u00e8me, r\u00e9f\u00e9rentiel, forces, axes, projections puis interpr\u00e9tation :\ncette m\u00e9thode deviendra le socle de tous les probl\u00e8mes de m\u00e9canique CPGE.\n<\/p>\n\n<div class=\"actions\" style=\"justify-content:center\">\n<a href=\"#cours\" class=\"btn gold\">\ud83d\udcda REVOIR LE COURS<\/a>\n<a href=\"#exercices\" class=\"btn glass\">\ud83e\udde9 EXERCICES<\/a>\n<a href=\"#qcm\" class=\"btn glass\">\u2753 REFAIRE LE QCM<\/a>\n<\/div>\n\n<\/div>\n<\/div>\n<\/section>\n\n<script>\nfunction mzaDynHint(id){\n const el=document.getElementById(id);\n if(!el)return;\n el.style.display = el.style.display===\"block\" ? \"none\" : \"block\";\n}\n\nfunction mzaDynScore(){\n const form=document.getElementById(\"dynQuiz\");\n const result=document.getElementById(\"dynResult\");\n\n let score=0;\n let complete=true;\n\n [\"n1\",\"n2\",\"n3\",\"n4\",\"n5\",\"n6\"].forEach(function(name){\n   const answer=form.querySelector('input[name=\"'+name+'\"]:checked');\n\n   if(!answer){\n     complete=false;\n   }else{\n     score+=Number(answer.value);\n   }\n });\n\n result.style.display=\"block\";\n\n if(!complete){\n   result.innerHTML=\"<strong>R\u00e9pondez aux 6 questions avant de valider.<\/strong>\";\n   return;\n }\n\n const pct=Math.round(score\/6*100);\n\n let level=\"Dynamique \u00e0 consolider\";\n if(pct>=50) level=\"Fondations acquises\";\n if(pct>=67) level=\"Bon niveau\";\n if(pct>=84) level=\"Tr\u00e8s bonne ma\u00eetrise\";\n if(pct===100) level=\"Excellent niveau CPGE\";\n\n result.innerHTML=\n \"<strong style='font-size:30px;color:#efd68c'>\"+pct+\"%<\/strong>\"+\n \"<p><b>\"+level+\"<\/b><\/p>\"+\n \"<p>Score : \"+score+\" \/ 6<\/p>\"+\n \"<p>Les r\u00e9ponses correctes et la correction d\u00e9taill\u00e9e restent masqu\u00e9es.<\/p>\";\n}\n<\/script>\n\n<\/div>\n&#8220;`\n","protected":false},"excerpt":{"rendered":"<p>&#8220;`html COURS 03 \u2022 PHYSIQUE CPGE Isoler.Projeter. R\u00e9soudre. La dynamique relie le mouvement aux interactions responsables de son \u00e9volution. Le c\u0153ur de la m\u00e9thode consiste \u00e0 choisir le syst\u00e8me, recenser les forces, appliquer la deuxi\u00e8me loi de Newton puis projeter intelligemment. \ud83d\udcda COMMENCER \ud83e\udde0 M\u00c9THODE \ud83e\udde9 EXERCICES \u2753 QCM 1. SYST\u00c8ME M\u00c9CANIQUE Avant toute \u00e9quation [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1578","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages\/1578","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/comments?post=1578"}],"version-history":[{"count":1,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages\/1578\/revisions"}],"predecessor-version":[{"id":1580,"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/pages\/1578\/revisions\/1580"}],"wp:attachment":[{"href":"https:\/\/maroczain.com\/scolaire.maroczain.com\/wp-json\/wp\/v2\/media?parent=1578"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}