{"id":537,"date":"2015-03-02T03:17:51","date_gmt":"2015-03-02T03:17:51","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=537"},"modified":"2024-09-02T17:19:10","modified_gmt":"2024-09-02T17:19:10","slug":"resolucao-comentada-da-fgv-2015","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/universidades-2015\/exercicios-resolvidos-da-fgv-2015\/resolucao-comentada-da-fgv-2015\/","title":{"rendered":"Resolu\u00e7\u00e3o comentada da FGV 2015"},"content":{"rendered":"

Resolu\u00e7\u00f5es<\/b><\/span><\/span><\/span><\/p>\n

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

\"\"<\/p>\n

02-<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

03- <\/b><\/span><\/span><\/span>O moimento das bolas sobre a mesa \u00e9 <\/b><\/span><\/span><\/span>horizontal e<\/b><\/span><\/span><\/span> durante o fen\u00f4meno <\/b><\/span><\/span><\/span>n\u00e3o ocorre varia\u00e7\u00e3o de energia potencial gravitacional<\/b><\/span><\/span><\/span> (a altura das bolas n\u00e3o est\u00e1 variando), <\/b><\/span><\/span><\/span>apenas h\u00e1 varia\u00e7\u00e3o de energia cin\u00e9tica.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

04-<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

05-<\/b><\/span><\/span><\/span><\/p>\n

\"\"06- <\/b><\/span><\/span><\/span>C\u00e1lculo da acelera\u00e7\u00e3o da gravidade na superf\u00edcie do planeta.<\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>Terra (ou qualquer outro planeta)<\/b><\/span><\/span><\/span> origina ao seu redor um <\/b><\/span><\/span><\/span>campo gravitacional<\/b><\/span><\/span><\/span> de maneira que qualquer <\/b><\/span><\/span><\/span>corpo de massa m<\/b><\/span><\/span><\/span>, quando colocado no interior desse campo fica sujeito \u00e0<\/b><\/span><\/span><\/span>uma for\u00e7a de atra\u00e7\u00e3o gravitacional F<\/b><\/span><\/span><\/span>g<\/b><\/span><\/span><\/sub><\/span>=GMm\/r<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>,\u00a0sendo, <\/b><\/span><\/span><\/span>G <\/b><\/span><\/span><\/span>a constante de gravita\u00e7\u00e3o universal, <\/b><\/span><\/span><\/span>M <\/b><\/span><\/span><\/span>a massa da Terra ou do planeta e <\/b><\/span><\/span><\/span>r <\/b><\/span><\/span><\/span>a dist\u00e2ncia do centro da Terra ou do <\/b><\/span><\/span><\/span>centro do planeta at\u00e9 o corpo<\/b><\/span><\/span><\/span> de massa <\/b><\/span><\/span><\/span>m.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Mas, esta <\/b><\/span><\/span><\/span>for\u00e7a que age sobre o corpo<\/b><\/span><\/span><\/span> ou sat\u00e9lite corresponde ao seu <\/b><\/span><\/span><\/span>pr\u00f3prio peso, tal que, P=mg.<\/b><\/span><\/span><\/span><\/p>\n

Portanto\u00a0 —\u00a0F<\/b><\/span><\/span><\/span>g<\/b><\/span><\/span><\/sub><\/span>=P\u00a0 — \u00a0GMm\/r<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>=mg\u00a0 — \u00a0<\/b><\/span><\/span><\/span>g=GM\/r<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

07-<\/b><\/span><\/span><\/span><\/p>\n

\"\"08-<\/b><\/span><\/span><\/span><\/p>\n

\"\"\"\"09-<\/b><\/span><\/span><\/span><\/p>\n

\"\"10-<\/b><\/span><\/span><\/span><\/p>\n

\"\"11- <\/b><\/span><\/span><\/span>2\u00aa<\/b><\/span><\/span><\/span> <\/b>lei da refra\u00e7\u00e3o <\/b><\/span><\/span><\/span>— Lei de seno do \u00e2ngulo Snell-Descartes – A rela\u00e7\u00e3o <\/b><\/span><\/span>entre o seno do \u00e2ngulo de incid\u00eancia e o<\/b><\/span><\/span><\/span> <\/b>de refra\u00e7\u00e3o<\/b><\/span><\/span><\/span> \u00e9 uma <\/b><\/span><\/span>grandeza constante<\/b><\/span><\/span><\/span> denominada <\/b><\/span><\/span>\u00edndice de refra\u00e7\u00e3o do segundo meio em rela\u00e7\u00e3o ao primeiro, ou seja,\u00a0 seni\/senr=n<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\/n<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>.\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

As <\/b><\/span><\/span>express\u00f5es acima<\/b><\/span><\/span><\/span> nos mostram que quando a luz <\/b><\/span><\/span>passar de um meio menos refringente (menor indice de refra\u00e7\u00e3o) para um meio mais refringente (maior \u00edndice de refra\u00e7\u00e3o),<\/b><\/span><\/span><\/span> o <\/b><\/span><\/span>\u00e2ngulo de refra\u00e7\u00e3o ser\u00e1 menor que o \u00e2ngulo de incid\u00eancia (ele se aproxima da normal) e menor ser\u00e1 a velocidade da luz nele. (figura abaixo)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Pelo <\/b><\/span><\/span>princ\u00edpio da reversibilidade (caminho inverso<\/b><\/span><\/span><\/span>), quando a luz <\/b><\/span><\/span>passa<\/b><\/span><\/span><\/span> de um meio <\/b><\/span><\/span>mais refringente para um menos refringente sua velocidade aumenta e ele se afasta da normal<\/b><\/span><\/span><\/span>.<\/span><\/p>\n

Observe na <\/b><\/span><\/span><\/span>figura do enunciado<\/b><\/span><\/span><\/span> que, quando <\/b><\/span><\/span><\/span>passa do ar para o pol\u00edmero o raio de luz se aproxima<\/b><\/span><\/span><\/span><\/b><\/p>\n

\"\"<\/p>\n

da normal<\/b><\/span><\/span><\/span>, o que implica que <\/b><\/span><\/span><\/span>n<\/b><\/span><\/span><\/span>po<\/b><\/span><\/span><\/sub><\/span> > n<\/b><\/span><\/span><\/span>ar<\/b><\/span><\/span><\/sub><\/span>, e que quando <\/b><\/span><\/span><\/span>passa do pol\u00edmero para o cristal o raio de luz se aproxima da normal e, n<\/b><\/span><\/span><\/span>cr<\/b><\/span><\/span><\/sub><\/span> > n<\/b><\/span><\/span><\/span>po<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Ent\u00e3o voc\u00ea ter\u00e1 que <\/b><\/span><\/span><\/span>n<\/b><\/span><\/span><\/span>cr<\/b><\/span><\/span><\/sub><\/span> > n<\/b><\/span><\/span><\/span>po<\/b><\/span><\/span><\/sub><\/span> > n<\/b><\/span><\/span><\/span>ar<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

R- B<\/b><\/span><\/span><\/span><\/p>\n

12-<\/b><\/span><\/span><\/span><\/p>\n

\"\"13-<\/b><\/span><\/span><\/span><\/p>\n

\"\"14-<\/b><\/span><\/span><\/span><\/p>\n

\"\"\"\"\"\"15- <\/b><\/span><\/span><\/span>A <\/b><\/span><\/span><\/span>intera\u00e7\u00e3o entre o n\u00facleo da Terra<\/b><\/span><\/span><\/span> (extremamente quente e l\u00edquido) e o <\/b><\/span><\/span><\/span>magma em torno dele<\/b><\/span><\/span><\/span> \u00e9 muito intensa e <\/b><\/span><\/span><\/span>origina as linhas magn\u00e9ticas que saem pelo p\u00f3lo sul e entram pelo p\u00f3lo norte, formando assim o\u00a0campo magn\u00e9tico terrestre.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Por\u00e9m algumas dessas linhas magn\u00e9ticas <\/b><\/span><\/span>n\u00e3o s\u00e3o conectadas<\/b><\/span><\/span><\/span> ao nosso planeta e se estendem indefinidamente pelo espa\u00e7o at\u00e9 encontrarem alguma barreira, como por exemplo, o <\/b><\/span><\/span>vento solar<\/b><\/span><\/span><\/span>, <\/b><\/span><\/span>formando assim a <\/b><\/span><\/span><\/span>Magnetosfera<\/b><\/span><\/span><\/span>\u00a0(uma esp\u00e9cie de envolt\u00f3rio do nosso planeta, formada pela<\/b><\/span><\/span><\/span><\/b><\/p>\n

intera\u00e7\u00e3o entre o nosso campo magn\u00e9tico e o vento solar).<\/b><\/span><\/span><\/span> A <\/b><\/span><\/span><\/span>Magnetosfera funciona como um<\/b><\/span><\/span><\/span> <\/b>colch\u00e3o protetor, existente entre os ventos solares e a pr\u00f3pria Terra,<\/b><\/span><\/span><\/span>nos protegendo de v\u00e1rias anomalias do espa\u00e7o, principalmente os ventos solares, a radia\u00e7\u00e3o solar e outros raios c\u00f3smicos.<\/b><\/span><\/span><\/span><\/p>\n

R- A<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

Voltar para os Exerc\u00edcios<\/a><\/span><\/h3>\n","protected":false},"excerpt":{"rendered":"

Resolu\u00e7\u00f5es 01- 02- 03- O moimento das bolas sobre a mesa \u00e9 horizontal e durante o fen\u00f4meno n\u00e3o ocorre varia\u00e7\u00e3o de energia potencial gravitacional (a altura das bolas n\u00e3o est\u00e1 variando), apenas h\u00e1 varia\u00e7\u00e3o de energia cin\u00e9tica. 04- 05- 06- C\u00e1lculo da acelera\u00e7\u00e3o da gravidade na superf\u00edcie do planeta. A Terra (ou qualquer outro planeta) origina ao seu redor um<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":535,"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-537","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/537","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=537"}],"version-history":[{"count":3,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/537\/revisions"}],"predecessor-version":[{"id":542,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/537\/revisions\/542"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/535"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=537"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}