{"id":4254,"date":"2018-12-22T02:38:17","date_gmt":"2018-12-22T02:38:17","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=4254"},"modified":"2024-08-22T13:29:36","modified_gmt":"2024-08-22T13:29:36","slug":"eletromagnetismo-01-imas-e-campo-magnetico","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/formulario\/eletromagnetismo-01-imas-e-campo-magnetico\/","title":{"rendered":"Eletromagnetismo 01 – IM\u00c3S E CAMPO MAGN\u00c9TICO"},"content":{"rendered":"

<\/a> Formul\u00e1rio completo de F\u00edsica com informa\u00e7\u00f5es \u00fateis <\/b><\/span><\/span><\/span><\/p>\n

(Dicas para vestibulares)<\/b><\/span><\/span><\/span><\/p>\n

Eletromagnetismo 01<\/b><\/span><\/span><\/span><\/p>\n

IM\u00c3S E CAMPO MAGN\u00c9TICO<\/b><\/span><\/span><\/span><\/p>\n

IM\u00c3S<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Atra\u00e7\u00e3o e repuls\u00e3o entre os polos de im\u00e3s<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Campo magn\u00e9tico<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Conven\u00e7\u00f5es sobre o campo magn\u00e9tico B<\/span><\/span><\/h1>\n

<\/p>\n

Campo magn\u00e9tico uniforme<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Campo magn\u00e9tico resultante<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Informa\u00e7\u00f5es \u00fateis <\/span><\/span><\/span>(dicas para vestibulares)<\/span><\/span><\/span><\/p>\n

A\u00a0<\/b><\/span><\/span>Terra se comporta como um grande im\u00e3<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>onde o\u00a0<\/b><\/span><\/span>polo Sul magn\u00e9tico est\u00e1 aproximadamente localizado no polo Norte geogr\u00e1fico e vice versa.<\/b><\/span><\/span><\/span><\/span><\/p>\n

Se voc\u00ea\u00a0<\/b><\/span><\/span>pendurar um im\u00e3 em forma de barra pelo seu centro<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>ou\u00a0<\/b><\/span><\/span>observar a agulha magn\u00e9tica<\/b><\/span><\/span>\u00a0de uma\u00a0<\/b><\/span><\/span>b\u00fassola<\/b><\/span><\/span> voc\u00ea ver\u00e1 que <\/b><\/span><\/span>seus polos ficam sempre alinhados na dire\u00e7\u00e3o <\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

norte-sul. <\/b><\/span><\/span>O\u00a0<\/b><\/span><\/span>polo que indicar o polo norte geogr\u00e1fico<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>recebe o nome de\u00a0<\/b><\/span><\/span>polo norte e estar\u00e1 indicando\u00a0<\/b><\/span><\/span>o\u00a0<\/b><\/span><\/span>polo sul magn\u00e9tico da Terra.<\/b><\/span><\/span><\/span><\/span><\/p>\n

O\u00a0<\/b><\/span><\/span>polo que indicar o polo sul geogr\u00e1fico<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>recebe o nome de\u00a0<\/b><\/span><\/span>polo sul\u00a0<\/b><\/span><\/span>e estar\u00e1 <\/b><\/span><\/span>indicando o polo norte magn\u00e9tico da Terra.\u00a0<\/b><\/span><\/span>T<\/b><\/span><\/span>udo isso ocorre\u00a0<\/b><\/span><\/span>porque polos de nomes opostos se atraem.<\/b><\/span><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>for\u00e7a de atra\u00e7\u00e3o entre um im\u00e3 e um peda\u00e7o de ferro<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>ou as <\/b><\/span><\/span><\/span>for\u00e7as de atra\u00e7\u00e3o ou de\u00a0<\/b><\/span><\/span><\/span>repuls\u00e3o\u00a0<\/b><\/span><\/span><\/span>entre dois im\u00e3s n\u00e3o \u00e9 de origem el\u00e9trica<\/b><\/span><\/span><\/span>, pois os <\/b><\/span><\/span><\/span>corpos n\u00e3o est\u00e3o eletrizados.
\n<\/b><\/span><\/span><\/span>Trata-se de\u00a0<\/b><\/span><\/span><\/span>for\u00e7as magn\u00e9ticas\u00a0<\/b><\/span><\/span><\/span>e que\u00a0<\/b><\/span><\/span><\/span>obedecem ao princ\u00edpio da a\u00e7\u00e3o e rea\u00e7\u00e3o<\/b><\/span><\/span><\/span> (terceira lei de Newton),\u00a0<\/b><\/span><\/span><\/span>pois tem a\u00a0<\/b><\/span><\/span><\/span>mesma intensidade, mesma dire\u00e7\u00e3o, mas sentidos opostos.<\/b><\/span><\/span><\/span><\/p>\n

Inseparabilidade dos polos magn\u00e9ticos<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

\u00a0<\/span>Se voc\u00ea\u00a0<\/b><\/span><\/span>quebrar um im\u00e3<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>e em seguida <\/b><\/span><\/span>continuar\u00a0<\/b><\/span><\/span>dividindo os im\u00e3s resultantes,<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>voc\u00ea <\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

observar\u00e1 que\u00a0<\/b><\/span><\/span>cada peda\u00e7o partido continuar\u00e1 sendo um novo im\u00e3 com dois polos, Norte e Sul de maneira que cada peda\u00e7o atraia o outro.\u00a0N\u00e3o existem polos isolados.<\/b><\/span><\/span><\/span><\/span><\/p>\n

Se voc\u00ea\u00a0<\/b><\/span><\/span>partir um im\u00e3 conforme a figura abaixo,<\/b><\/span><\/span>\u00a0a\u00a0<\/b><\/span><\/span>for\u00e7a entre eles ser\u00e1 de repuls\u00e3o.<\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Rela\u00e7\u00e3o entre a imanta\u00e7\u00e3o e os im\u00e3s elementares<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

Um\u00a0<\/b><\/span><\/span>bloco, por exemplo, de ferro, pode encontrar-se:<\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Para\u00a0<\/b><\/span><\/span>magnetizar uma barra de ferro<\/b><\/span><\/span> (por exemplo, um prego de a\u00e7o)\u00a0<\/b><\/span><\/span>de forma tempor\u00e1ria basta\u00a0<\/b><\/span><\/span>deslizar um \u00edm\u00e3 sobre o prego da ponta A em dire\u00e7\u00e3o \u00e0 outra ponta B,\u00a0repetidas vezes,<\/b><\/span><\/span> <\/b>sempre\u00a0de A para B,<\/b><\/span><\/span>\u00a0conforme a figura.\u00a0<\/b><\/span><\/span>Observe que\u00a0<\/b><\/span><\/span>estamos <\/b><\/span><\/span>esfregando o polo norte no prego, de A para B.<\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Depois que o\u00a0<\/b><\/span><\/span>prego fica imantado e o im\u00e3 permanente \u00e9 afastado<\/b><\/span><\/span>,<\/b><\/span><\/span> a\u00a0<\/b><\/span><\/span>parte direita do prego<\/b><\/span><\/span> <\/b>(B)<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>que ficou imantado <\/b><\/span><\/span>(cabe\u00e7a)<\/b><\/span><\/span> \u00e9 o\u00a0<\/b><\/span><\/span>polo sul<\/b><\/span><\/span> <\/b>e a\u00a0<\/b><\/span><\/span>parte <\/b><\/span><\/span>esquerda A, (ponta), \u00e9 o polo norte.<\/b><\/span><\/span> \u00a0<\/b><\/span><\/span><\/span><\/span><\/p>\n

A\u00a0<\/b><\/span><\/span>localiza\u00e7\u00e3o dos polos de um im\u00e3<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>depende de sua\u00a0<\/b><\/span><\/span>forma geom\u00e9trica<\/b><\/span><\/span>, mas <\/b><\/span><\/span>sempre se<\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

localizam em oposi\u00e7\u00e3o em rela\u00e7\u00e3o a um plano de simetria.<\/b><\/span><\/span><\/span><\/span><\/p>\n

Se um\u00a0<\/b><\/span><\/span>\u00edm\u00e3 permanente,<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>em forma de\u00a0<\/b><\/span><\/span>\u201cferradura\u201d<\/b><\/span><\/span>,<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>cujos\u00a0<\/b><\/span><\/span>polos norte e sul est\u00e3o indicados<\/b><\/span><\/span> <\/b>na<\/b><\/span><\/span><\/span><\/span><\/p>\n

\u00a0<\/span>figura I,<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>\u00e9\u00a0<\/b><\/span><\/span>dividido em tr\u00eas partes (figura II)<\/b><\/span><\/span>,\u00a0<\/b><\/span><\/span>as\u00a0<\/b><\/span><\/span>partes 1, 2 e 3 formar\u00e3o tr\u00eas novos <\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

im\u00e3s\u00a0<\/b><\/span><\/span>(lembre-se de que \u00e9 imposs\u00edvel obter um polo isolado) <\/b><\/span><\/span>com as\u00a0<\/b><\/span><\/span>polaridades indicadas na figura III.<\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

<\/p>\n

Influ\u00eancia de um campo magn\u00e9tico uniforme sobre um im\u00e3<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

\u00a0<\/span><\/p>\n

Os\u00a0<\/b><\/span><\/span>im\u00e3s da figura abaixo\u00a0<\/b><\/span><\/span>est\u00e3o colocados no\u00a0<\/b><\/span><\/span>interior de um campo magn\u00e9tico <\/b><\/span><\/span><\/span><\/span><\/p>\n

uniforme.<\/b><\/span><\/span><\/span><\/span><\/p>\n

Considere\u00a0<\/b><\/span><\/span>somente as a\u00e7\u00f5es magn\u00e9ticas\u00a0<\/b><\/span><\/span>e\u00a0<\/b><\/span><\/span>classifique<\/b><\/span><\/span>, em cada caso, o <\/b><\/span><\/span>tipo de equil\u00edbrio<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/p>\n

Os <\/b><\/span><\/span>im\u00e3s se orientam sempre <\/b><\/span><\/span><\/span><\/span><\/p>\n

com o polo norte no sentido de\u00a0<\/b><\/span><\/span><\/span><\/span><\/p>\n

, ou seja, para a direita.<\/b><\/span><\/span><\/span><\/span><\/p>\n

Assim\u00a0<\/b><\/span><\/span>no <\/b><\/span><\/span>polo norte surge uma <\/b><\/span><\/span><\/span><\/span><\/p>\n

for\u00e7a puxando-o para a direita<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span><\/span><\/p>\n

e no\u00a0<\/b><\/span><\/span>polo sul<\/b><\/span><\/span> surge <\/b><\/span><\/span>uma for\u00e7a<\/b><\/span><\/span><\/span><\/span><\/p>\n

puxando-o para a esquerda.<\/b><\/span><\/span><\/span><\/span><\/p>\n

Na\u00a0<\/b><\/span><\/span>figura 1,<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>se voc\u00ea\u00a0<\/b><\/span><\/span>tirar <\/b><\/span><\/span>(girar) <\/b><\/span><\/span><\/span><\/span><\/p>\n

um pouco o im\u00e3 da posi\u00e7\u00e3o em<\/b><\/span><\/span><\/span><\/span><\/p>\n

que ele se encontra<\/b><\/span><\/span>,<\/b><\/span><\/span> <\/b>ele\u00a0<\/b><\/span><\/span>girar\u00e1,<\/b><\/span><\/span><\/span><\/span><\/p>\n

pois est\u00e1\u00a0<\/b><\/span><\/span>em equil\u00edbrio inst\u00e1vel\u00a0<\/b><\/span><\/span><\/span><\/span><\/p>\n

at\u00e9 atingir o equil\u00edbrio est\u00e1vel <\/b><\/span><\/span><\/span><\/span><\/p>\n

(polo norte para a direita).
\n<\/b><\/span><\/span>Na\u00a0<\/b><\/span><\/span>figura 2,<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>se voc\u00ea\u00a0<\/b><\/span><\/span>tirar <\/b><\/span><\/span>(girar)\u00a0<\/b><\/span><\/span>um pouco o im\u00e3\u00a0<\/b><\/span><\/span>da posi\u00e7\u00e3o em que ele se encontra<\/b><\/span><\/span>,<\/b><\/span><\/span><\/span><\/span><\/p>\n

ele retornar\u00e1\u00a0<\/b><\/span><\/span>a\u00a0<\/b><\/span><\/span>ela, pois est\u00e1 em\u00a0equil\u00edbrio est\u00e1vel.<\/b><\/span><\/span>
\n<\/b><\/span><\/span>Na\u00a0<\/b><\/span><\/span>figura 3<\/b><\/span><\/span>,<\/b><\/span><\/span> ele est\u00e1 em\u00a0<\/b><\/span><\/span>equil\u00edbrio inst\u00e1vel<\/b><\/span><\/span>,\u00a0<\/b><\/span><\/span>pois girar\u00e1 de 90<\/b><\/span><\/span>o<\/b><\/span><\/sup><\/span>\u00a0no sentido anti-hor\u00e1rio at\u00e9 atingir o equil\u00edbrio est\u00e1vel.<\/b><\/span><\/span><\/span><\/span><\/p>\n

\u00a0<\/span><\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Formul\u00e1rio completo de F\u00edsica com informa\u00e7\u00f5es \u00fateis (Dicas para vestibulares) Eletromagnetismo 01 IM\u00c3S E CAMPO MAGN\u00c9TICO IM\u00c3S Atra\u00e7\u00e3o e repuls\u00e3o entre os polos de im\u00e3s Campo magn\u00e9tico Conven\u00e7\u00f5es sobre o campo magn\u00e9tico B Campo magn\u00e9tico uniforme Campo magn\u00e9tico resultante Informa\u00e7\u00f5es \u00fateis (dicas para vestibulares) A\u00a0Terra se comporta como um grande im\u00e3\u00a0onde o\u00a0polo Sul magn\u00e9tico est\u00e1 aproximadamente localizado no polo Norte<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":3987,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-4254","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4254","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/comments?post=4254"}],"version-history":[{"count":1,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4254\/revisions"}],"predecessor-version":[{"id":4255,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4254\/revisions\/4255"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3987"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=4254"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}