{"id":16689,"date":"2024-09-20T12:00:30","date_gmt":"2024-09-20T15:00:30","guid":{"rendered":"https:\/\/xequematenem.com.br\/blog\/?p=16689"},"modified":"2024-09-20T12:00:33","modified_gmt":"2024-09-20T15:00:33","slug":"questao-113-enem-2019","status":"publish","type":"post","link":"https:\/\/xequematenem.com.br\/blog\/questao-113-enem-2019\/","title":{"rendered":"Quest\u00e3o 113 &#8211; ENEM 2019"},"content":{"rendered":"\n<p>O espectr\u00f4metro de massa de tempo de voo \u00e9 um dispositivo utilizado para medir a massa de \u00edons. Nele, um \u00edon de carga el\u00e9trica q \u00e9 lan\u00e7ado em uma regi\u00e3o de campo magn\u00e9tico constante B, descrevendo uma trajet\u00f3ria helicoidal, conforme a figura. Essa trajet\u00f3ria \u00e9 formada pela composi\u00e7\u00e3o de um movimento circular uniforme no plano yz e uma transla\u00e7\u00e3o ao longo do eixo x. A vantagem desse dispositivo \u00e9 que a velocidade angular do movimento helicoidal do \u00edon \u00e9 independente de sua velocidade inicial. O dispositivo ent\u00e3o mede o tempo t de voo para N voltas do \u00edon. Logo, com base nos valores q, B, N e t, pode-se determinar a massa do \u00edon.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"339\" height=\"251\" src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-508.png\" alt=\"\" class=\"wp-image-16690\" title=\"\" srcset=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-508.png 339w, https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-508-300x222.png 300w\" sizes=\"(max-width: 339px) 100vw, 339px\" \/><\/figure>\n\n\n\n<p>A massa do \u00edon medida por esse dispositivo ser\u00e1&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" data-src=\"https:\/\/lh7-rt.googleusercontent.com\/docsz\/AD_4nXd_0MJHo31M3F1aynpzU-eP2SuUSabmCkQ9yC-X0jpUsOqFSy_xPdKe-Uju4qn68m66qk7qvVUmR23HTeCzg6Xj9gWWWKZOg6fQ94oe5yAt9s90xI8xadapBAwu-F62xXB2QCmaDDCcYRWd-FUzWalct-0p?key=cZZoT8Y6vO0sxb39wzql9g\" alt=\"\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\"><\/figure>\n\n\n\n<p><strong>Solu\u00e7\u00e3o<\/strong><\/p>\n\n\n\n<p>A for\u00e7a que atuando no sistema \u00e9 a for\u00e7a magn\u00e9tica F<sub>B<\/sub> dada por:\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"69\" height=\"27\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-509.png\" alt=\"\" class=\"wp-image-16691 lazyload\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 69px; --smush-placeholder-aspect-ratio: 69\/27;\"><\/figure>\n\n\n\n<p>Como a part\u00edcula est\u00e1 girando, podemos associar essa for\u00e7a a uma for\u00e7a centr\u00edpeta<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"153\" height=\"212\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-510.png\" alt=\"\" class=\"wp-image-16692 lazyload\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 153px; --smush-placeholder-aspect-ratio: 153\/212;\"><\/figure>\n\n\n\n<p>como o caminho que a part\u00edcula percorre \u00e9 uma circunfer\u00eancia, temos que&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"120\" height=\"90\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-511.png\" alt=\"\" class=\"wp-image-16693 lazyload\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 120px; --smush-placeholder-aspect-ratio: 120\/90;\"><\/figure>\n\n\n\n<p>Para N voltas, temos N circunfer\u00eancias:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"85\" height=\"28\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-513.png\" alt=\"\" class=\"wp-image-16695 lazyload\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 85px; --smush-placeholder-aspect-ratio: 85\/28;\"><\/figure>\n\n\n\n<p>Assim:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"138\" height=\"161\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/09\/image-512.png\" alt=\"\" class=\"wp-image-16694 lazyload\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 138px; --smush-placeholder-aspect-ratio: 138\/161;\"><\/figure>\n\n\n\n<p><strong>Alternativa A<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>O espectr\u00f4metro de massa de tempo de voo \u00e9 um dispositivo utilizado para medir a massa de \u00edons. Nele, um \u00edon de carga el\u00e9trica q \u00e9 lan\u00e7ado em uma regi\u00e3o de campo magn\u00e9tico constante B, descrevendo uma trajet\u00f3ria helicoidal, conforme a figura. Essa trajet\u00f3ria \u00e9 formada pela composi\u00e7\u00e3o de um movimento circular uniforme no plano [&hellip;]<\/p>\n","protected":false},"author":11,"featured_media":16690,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17,19],"tags":[],"area-do-conhecimento":[116,121],"assunto":[],"class_list":["post-16689","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-questoes-do-enem","category-19","area-do-conhecimento-ciencias-da-natureza-e-suas-tecnologias","area-do-conhecimento-fisica"],"_links":{"self":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts\/16689","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/comments?post=16689"}],"version-history":[{"count":1,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts\/16689\/revisions"}],"predecessor-version":[{"id":16696,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts\/16689\/revisions\/16696"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/media\/16690"}],"wp:attachment":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/media?parent=16689"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/categories?post=16689"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/tags?post=16689"},{"taxonomy":"area-do-conhecimento","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/area-do-conhecimento?post=16689"},{"taxonomy":"assunto","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/assunto?post=16689"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}