{"id":1199,"date":"2022-05-05T15:20:57","date_gmt":"2022-06-24T09:56:33","guid":{"rendered":"https:\/\/experiments.school\/?post_type=product&p=1199"},"modified":"2022-07-01T10:22:52","modified_gmt":"2022-07-01T08:22:52","slug":"165-balle-a-sauter","status":"publish","type":"product","link":"https:\/\/experiments.school\/fr\/produkt\/165-balle-a-sauter\/","title":{"rendered":"165 – Balle \u00e0 sauter"},"content":{"rendered":"","protected":false},"excerpt":{"rendered":"

Balle <\/span>rebondissante<\/span> \u00e9lastique<\/span>\u00a0<\/span><\/span>\u00a0<\/span><\/strong><\/h2>\n

Introduction \u00e0:\u00a0 <\/span>
\n<\/span><\/h2>\n

Conversions d’\u00e9nergie, \u00e9nergie potentielle, \u00e9nergie cin\u00e9tique, \u00e9nergie de tension, choc \u00e9lastique<\/span>\u00a0<\/span><\/p>\n[video width=\"1080\" height=\"1920\" mp4=\"https:\/\/experiments.school\/wp-content\/uploads\/2022\/05\/165-2.mp4\"][\/video]\n

<\/h2>\n

Mat\u00e9riel:\u00a0<\/span>\u00a0<\/span><\/h2>\n
    \n
  • Balle sautillante \/ balle flamm\u00e9e \/ balle de tennis \/ balle \u00e9lastique\u00a0<\/span>\u00a0<\/span><\/li>\n
  • r\u00e8gle gradu\u00e9e \/ m\u00e8tre\u00a0<\/span>\u00a0<\/span><\/li>\n
  • t\u00e9l\u00e9phone portable avec fonction vid\u00e9o \/ cam\u00e9ra vid\u00e9o\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

    R\u00e9alisation:\u00a0<\/span>\u00a0<\/span><\/h2>\n

    Nous laissons tomber la balle devant le m\u00e8tre d’une hauteur d’environ un m\u00e8tre sur une surface dure (sol) et la faisons rebondir plusieurs fois. Ce faisant, nous filmons le processus au ralenti.\u00a0<\/span>\u00a0<\/span><\/p>\n

    Observation:\u00a0<\/span>\u00a0<\/span><\/h2>\n
      \n
    • La balle acc\u00e9l\u00e8re en chute libre.\u00a0<\/span>\u00a0<\/span><\/li>\n
    • Lors de l’impact, la direction de sa vitesse s’inverse.\u00a0<\/span>\u00a0<\/span><\/li>\n
    • Puis elle ralentit \u00e0 nouveau et s’arr\u00eate bri\u00e8vement.\u00a0<\/span>\u00a0<\/span><\/li>\n
    • Dans le ralenti de la vid\u00e9o, et encore mieux dans l’image fixe, on peut lire la hauteur de vol sur la barre de mesure.\u00a0<\/span>\u00a0<\/span><\/li>\n
    • La chute libre commence alors \u00e0 nouveau.\u00a0<\/span>\u00a0<\/span><\/li>\n
    • La hauteur de vol diminue apr\u00e8s chaque impact sur le sol.\u00a0<\/span>\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

      Explications : le poids de l’air :\u00a0\u00a0<\/span>\u00a0<\/span><\/h2>\n
        \n
      • La force du poids agit vers le bas.\u00a0\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Lors de l’impact, la balle est d\u00e9form\u00e9e \u00e9lastiquement et subit ainsi un coup vers le haut.\u00a0\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Maintenant, seule la force du poids agit jusqu’au prochain impact.\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Du point de vue \u00e9nerg\u00e9tique, l’\u00e9nergie en hauteur de la balle se transforme progressivement en \u00e9nergie cin\u00e9tique.\u00a0\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Lors de l’impact, l’\u00e9nergie cin\u00e9tique se transforme en \u00e9nergie de tension, qui se transforme ensuite \u00e0 nouveau en \u00e9nergie cin\u00e9tique, etc.\u00a0<\/span>\u00a0<\/span><\/li>\n
      • Les hauteurs de vol d\u00e9croissantes nous permettent de conclure \u00e0 une perte d’\u00e9nergie m\u00e9canique, qui se produit \u00e0 chaque impact.\u00a0\u00a0<\/span>\u00a0<\/span><\/li>\n
      • La d\u00e9formation de la balle g\u00e9n\u00e8re des frottements et donc de l’\u00e9nergie thermique.\u00a0<\/span>\u00a0<\/span><\/li>\n<\/ul>\n

        Potentiel didactique:\u00a0<\/span>\u00a0<\/span><\/h2>\n

        Il est int\u00e9ressant de se demander si le m\u00eame pourcentage d’\u00e9nergie m\u00e9canique est perdu \u00e0 chaque impact. On peut le constater en observant la succession des hauteurs de vol.<\/span>\u00a0<\/span><\/p>\n","protected":false},"featured_media":1464,"template":"","meta":[],"product_brand":[],"product_cat":[913,919,928,699],"product_tag":[],"class_list":{"0":"post-1199","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-4-vitesse-acceleration-inertie","7":"product_cat-6-chute-libre-chute-avec-resistance-de-lair","8":"product_cat-9-formes-denergie-conservation-de-lenergie","9":"product_cat-a-mecanique","10":"","11":"woocommerce-text-align-left","12":"woocommerce-image-align-center","14":"first","15":"instock","16":"shipping-taxable","17":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/product\/1199","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/media\/1464"}],"wp:attachment":[{"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/media?parent=1199"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/product_brand?post=1199"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/product_cat?post=1199"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/experiments.school\/fr\/wp-json\/wp\/v2\/product_tag?post=1199"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}