{"id":3476,"date":"2018-01-19T01:22:41","date_gmt":"2018-01-19T01:22:41","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=3476"},"modified":"2024-09-04T12:48:37","modified_gmt":"2024-09-04T12:48:37","slug":"resolucao-comentada-das-questoes-de-fisica-da-unicamp-2018","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/universidades-2018\/unicamp\/resolucao-comentada-das-questoes-de-fisica-da-unicamp-2018\/","title":{"rendered":"Resolu\u00e7\u00e3o comentada das quest\u00f5es de F\u00cdSICA da UNICAMP-2018"},"content":{"rendered":"

Resolu\u00e7\u00e3o comentada das quest\u00f5es de F\u00cdSICA da <\/b><\/span><\/span><\/span><\/p>\n

UNICAMP-2018<\/b><\/span><\/span><\/span><\/p>\n

01- <\/b><\/span><\/span><\/span>1. Condu\u00e7\u00e3o<\/b><\/span><\/span> \"\"<\/b><\/span><\/span> <\/b>O\u00a0<\/b><\/span><\/span>calor,<\/b><\/span><\/span> devido ao <\/b><\/span><\/span>contato entre o c\u00e3o e ch\u00e3o, <\/b><\/span><\/span>\u00e9 <\/b><\/span><\/span>conduzido<\/b><\/span><\/span> do <\/b><\/span><\/span>solo para o c\u00e3o<\/b><\/span><\/span>, <\/b><\/span><\/span>sem <\/b><\/span><\/span>que haja <\/b><\/span><\/span>deslocamento das part\u00edculas.<\/b><\/span><\/span><\/span><\/span><\/p>\n

2. Evapora\u00e7\u00e3o<\/b><\/span><\/span> \"\" <\/b><\/span><\/span>A <\/b><\/span><\/span>l\u00edngua <\/b><\/span><\/span>do c\u00e3o <\/b><\/span><\/span>libera calor <\/b><\/span><\/span>para o meio ambiente <\/b><\/span><\/span>pela evapora\u00e7\u00e3o da saliva.\u00a0<\/b><\/span><\/span><\/span><\/span><\/p>\n

3. Convec\u00e7\u00e3o<\/b><\/span><\/span>\u00a0\"\" <\/b><\/span>Trata-se da <\/b><\/span><\/span>transfer\u00eancia de energia t\u00e9rmica <\/b><\/span><\/span>(calor) pela mat\u00e9ria <\/b><\/span><\/span>(no caso, ar) <\/b><\/span><\/span>em <\/b><\/span><\/span>movimento devido \u00e0 diferen\u00e7a de densidades, ou de temperatura, dessa mat\u00e9ria (ar)<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

O <\/b><\/span><\/span>c\u00e3o transfere calor para o ar pr\u00f3ximo aquecendo-o, <\/b><\/span><\/span>ficando <\/b><\/span><\/span>mais leve e subindo, <\/b><\/span><\/span>originando <\/b><\/span><\/span>correntes de convec\u00e7\u00e3o.<\/b><\/span><\/span><\/span><\/span><\/p>\n

4. Radia\u00e7\u00e3o<\/b><\/span><\/span> \"\" <\/b><\/span><\/span>Fen\u00f4meno no qual a <\/b><\/span><\/span>energia emitida pelo Sol chega at\u00e9 a Terra pelo v\u00e1cuo <\/b><\/span><\/span>atrav\u00e9s das <\/b><\/span><\/span>ondas eletromagn\u00e9ticas, inclusive o infravermelho (radia\u00e7\u00e3o t\u00e9rmica).<\/b><\/span><\/span><\/span><\/span><\/p>\n

5. Radia\u00e7\u00e3o<\/b><\/span><\/span> \"\"<\/b><\/span><\/span> Radia\u00e7\u00e3o t\u00e9rmica <\/b><\/span><\/span>(infravermelho, ondas de calor) <\/b><\/span><\/span>s\u00e3o<\/b><\/span><\/span> emitidas do corpo do c\u00e3o <\/b><\/span><\/span>para o<\/b><\/span><\/span> meio ambiente.<\/b><\/span><\/span><\/span><\/span><\/p>\n

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

02- <\/b><\/span><\/span><\/span>Quando o <\/b><\/span><\/span><\/span>combust\u00edvel est\u00e1 queimando, <\/b><\/span><\/span><\/span>est\u00e1 ocorrendo uma <\/b><\/span><\/span><\/span>transforma\u00e7\u00e3o qu\u00edmica. <\/b><\/span><\/span><\/span>Nela est\u00e1 ocorrendo uma <\/b><\/span><\/span><\/span>transforma\u00e7\u00e3o de energia qu\u00edmica em energia t\u00e9rmica.<\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>movimenta\u00e7\u00e3o das turbinas <\/b><\/span><\/span><\/span>pelo <\/b><\/span><\/span><\/span>vapor de \u00e1gua <\/b><\/span><\/span><\/span>est\u00e1 transformando <\/b><\/span><\/span><\/span>energia t\u00e9rmica em mec\u00e2nica e \u00e9 um fen\u00f4meno f\u00edsico. <\/b><\/span><\/span><\/span><\/p>\n

No <\/b><\/span><\/span><\/span>interior do gerador <\/b><\/span><\/span><\/span>a <\/b><\/span><\/span><\/span>rota\u00e7\u00e3o do eixo <\/b><\/span><\/span><\/span>do d\u00ednamo est\u00e1 transformando <\/b><\/span><\/span><\/span>energia mec\u00e2nica em energia el\u00e9trica por indu\u00e7\u00e3o eletromagn\u00e9tica. (transforma\u00e7\u00e3o f\u00edsica).<\/b><\/span><\/span><\/span><\/p>\n

Ent\u00e3o teremos <\/b><\/span><\/span><\/span>uma transforma\u00e7\u00e3o qu\u00edmica, duas transforma\u00e7\u00f5es f\u00edsicas e pelo menos tr\u00eas tipos de energia.<\/b><\/span><\/span><\/span><\/p>\n

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

03- <\/b><\/span><\/span><\/span>Enquanto o <\/b><\/span><\/span><\/span>gelo n\u00e3o se transformar totalmente em \u00e1gua<\/b><\/span><\/span><\/span> (fus\u00e3o do gelo) a <\/b><\/span><\/span><\/span>temperatura do sistema permanece constante (0<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>C).<\/b><\/span><\/span><\/span><\/p>\n

A <\/b><\/span><\/span><\/span>massa de gelo que se transforma em \u00e1gua \u00e9 a mesma <\/b><\/span><\/span><\/span>e, como a <\/b><\/span><\/span><\/span>densidade da \u00e1gua \u00e9 maior <\/b><\/span><\/span><\/span>que <\/b><\/span><\/span><\/span>a do gelo <\/b><\/span><\/span><\/span>(gelo menos denso \u201cmais leve\u201d flutua na \u00e1gua) <\/b><\/span><\/span><\/span>um volume de mesma massa de \u00e1gua \u00e9 menor que o de mesma massa de gelo, <\/b><\/span><\/span><\/span>pois a <\/b><\/span><\/span><\/span>express\u00e3o d\"\", <\/b><\/span><\/span><\/span>mostra que sendo <\/b><\/span><\/span><\/span>m constante, densidade e volume s\u00e3o inversamente proporcionais (V<\/b><\/span><\/span><\/span>\u00e1gua<\/b><\/span><\/span><\/sub><\/span> < V<\/b><\/span><\/span><\/span>gelo<\/b><\/span><\/span><\/sub><\/span>).<\/b><\/span><\/span><\/span><\/p>\n

\u00c0 medida que o <\/b><\/span><\/span><\/span>gelo vai derretendo o volume de \u00e1gua l\u00edquida V<\/b><\/span><\/span><\/span>\u00e1gua<\/b><\/span><\/span><\/sub><\/span> do sistema vai aumentando <\/b><\/span><\/span><\/span>e o respectivo <\/b><\/span><\/span><\/span>volume de gelo que era essa \u00e1gua (V<\/b><\/span><\/span><\/span>gelo<\/b><\/span><\/span><\/sub><\/span>) diminuindo, <\/b><\/span><\/span><\/span>o que provoca uma <\/b><\/span><\/span><\/span>diminui\u00e7\u00e3o do volume total do sistema, pois V<\/b><\/span><\/span><\/span>\u00e0gua<\/b><\/span><\/span><\/sub><\/span> < V<\/b><\/span><\/span><\/span>gelo<\/b><\/span><\/span><\/sub><\/span>).<\/b><\/span><\/span><\/span><\/p>\n

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

04- <\/b><\/span><\/span><\/span>Sendo que o <\/b><\/span><\/span><\/span>enunciado afirma que o peso e consequentemente a massa (P = m.g, com g constante) dos objetos (tri\u00e2ngulos) <\/b><\/span><\/span><\/span>\u00e9 <\/b><\/span><\/span><\/span>proporcional \u00e0 sua \u00e1rea, <\/b><\/span><\/span><\/span>vamos <\/b><\/span><\/span><\/span>calcular a \u00e1rea <\/b><\/span><\/span><\/span>de <\/b><\/span><\/span><\/span>cada tri\u00e2ngulo.<\/b><\/span><\/span><\/span><\/p>\n

Como o enunciado afirma que a <\/b><\/span><\/span><\/span>hipotenusa do tri\u00e2ngulo ret\u00e2ngulo <\/b><\/span><\/span><\/span>tem o <\/b><\/span><\/span><\/span>mesmo comprimento que os lados do tri\u00e2ngulo equil\u00e1tero, vamos denomina-los de \"\".<\/b><\/span><\/span><\/span><\/p>\n

C\u00e1lculo da \u00e1rea S do tri\u00e2ngulo equil\u00e1tero<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

C\u00e1lculo da \u00e1rea S do tri\u00e2ngulo is\u00f3sceles<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

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

\"\"<\/p>\n

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

Express\u00e3o matem\u00e1tica da acelera\u00e7\u00e3o da gravidade<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

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

Defini\u00e7\u00e3o do Teorema da Energia Cin\u00e9tica<\/b><\/span><\/span><\/span>: \u201cO\u00a0<\/b><\/span><\/span><\/span>trabalho da resultante\u00a0<\/b><\/span><\/span><\/span>de <\/b><\/span><\/span><\/span>todas<\/b><\/span><\/span><\/span>\u00a0as for\u00e7as que agem sobre um corpo\u00a0<\/b><\/span><\/span><\/span>\u00e9 igual \u00e0 varia\u00e7\u00e3o da energia cin\u00e9tica sofrida pelo corpo\u201d<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

As express\u00f5es acima\u00a0<\/b><\/span><\/span><\/span>s\u00e3o v\u00e1lidas seja a for\u00e7a resultante conservativa ou n\u00e3o.<\/b><\/span><\/span><\/span><\/p>\n

S\u00e3o dados:<\/b><\/span><\/span><\/span> massa do sat\u00e9lite <\/b><\/span><\/span><\/span>m = 6,0.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span> kg \"\"<\/b><\/span><\/span><\/span> velocidade inicial do sat\u00e9lite <\/b><\/span><\/span><\/span>V<\/b><\/span><\/span><\/span>i<\/b><\/span><\/span><\/sub><\/span> = 0 \"\"<\/b><\/span><\/span><\/span> velocidade final do sat\u00e9lite <\/b><\/span><\/span><\/span>V<\/b><\/span><\/span><\/span>f<\/b><\/span><\/span><\/sub><\/span> = 3,0.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span> m\/s.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

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

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

\"\"<\/p>\n

Causa da sustenta\u00e7\u00e3o de um avi\u00e3o<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

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

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

Quantidade de energia liberada na combust\u00e3o completa de certa massa de gelo \"\" <\/b><\/span><\/span><\/span>E <\/b><\/span><\/span><\/span>= 7,2 MJ = <\/b><\/span><\/span><\/span>7,2.10<\/b><\/span><\/span><\/span>6<\/b><\/span><\/span><\/sup><\/span> J.<\/b><\/span><\/span><\/span><\/p>\n

Pot\u00eancia<\/b><\/span><\/span><\/span> do painel de LEDs \"\" <\/b><\/span><\/span><\/span>P<\/b><\/span><\/span><\/span> = 2 kW <\/b><\/span><\/span><\/span>= 2.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span> W.<\/b><\/span><\/span><\/span><\/p>\n

Intervalo de tempo<\/b><\/span><\/span><\/span> de funcionamento do LEDs \"\" <\/b><\/span><\/span><\/span>\u2206t = ? <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

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

10- <\/b><\/span><\/span><\/span>S\u00e3o fornecidos: <\/b><\/span><\/span><\/span>Volume de \u00e1gua \"\" <\/b><\/span><\/span><\/span>V = 500 L; <\/b><\/span><\/span><\/span>Varia\u00e7\u00e3o de temperatura da \u00e1gua \"\" <\/b><\/span><\/span><\/span>\u2206t =<\/b><\/span><\/span><\/span> (47 \u2013 20) = <\/b><\/span><\/span><\/span>27 <\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>C;<\/b><\/span><\/span><\/span> Densidade da \u00e1gua \"\" <\/b><\/span><\/span><\/span>d = 1 kg\/L; <\/b><\/span><\/span><\/span>Calor espec\u00edfico da \u00e1gua \"\" <\/b><\/span><\/span><\/span>c <\/b><\/span><\/span><\/span>= 4 kJ\/kg<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>C <\/b><\/span><\/span><\/span>= 4.10<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sup><\/span> J\/kg<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>C<\/b><\/span><\/span><\/span> e<\/b><\/span><\/span><\/span><\/p>\n

1 kWh = 3,6.10<\/b><\/span><\/span><\/span>6<\/b><\/span><\/span><\/sup><\/span> J.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

11- <\/b><\/span><\/span><\/span>A <\/b><\/span><\/span><\/span>figura abaixo <\/b><\/span><\/span><\/span>mostra um desses <\/b><\/span><\/span><\/span>isolantes topol\u00f3gicos <\/b><\/span><\/span><\/span>e, observe que a <\/b><\/span><\/span><\/span>tens\u00e3o U \u00e9 a mesma <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

para <\/b><\/span><\/span><\/span>cada resist\u00eancia (da superf\u00edcie e do interior) e que elas est\u00e3o associadas em paralelo. <\/b><\/span><\/span><\/span><\/p>\n

Caracter\u00edsticas da associa\u00e7\u00e3o paralelo<\/b><\/span><\/span><\/span><\/span><\/p>\n

\u00a0\"\"\u00a0\u00a0Os\u00a0<\/b><\/span><\/span>resistores s\u00e3o associados pelos seus terminais<\/b><\/span><\/span>, ou seja,\u00a0<\/b><\/span><\/span>todos saem de um mesmo ponto e todos chegam a um mesmo ponto.<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"\u00a0A\u00a0<\/b><\/span><\/span>diferen\u00e7a de potencial (tens\u00e3o) U<\/b><\/span><\/span>\u00a0de\u00a0<\/b><\/span><\/span>toda a associa\u00e7\u00e3o (entre A e B) \u00e9 a mesma\u00a0para todos os resistores<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"\u00a0\u00a0A\u00a0<\/b><\/span><\/span>corrente total i<\/b><\/span><\/span>\u00a0\u00e9 a\u00a0<\/b><\/span><\/span>soma das correntes parciais<\/b><\/span><\/span>, ou seja,\u00a0i = i<\/b><\/span><\/span>1<\/b><\/span><\/sub><\/span>\u00a0+ i<\/b><\/span><\/span>2<\/b><\/span><\/sub><\/span>\u00a0+ i<\/b><\/span><\/span>3<\/b><\/span><\/sub><\/span><\/span><\/span><\/p>\n

F\u00f3rmulas v\u00e1lidas para a associa\u00e7\u00e3o paralelo<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

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

\"\"<\/p>\n

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

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

\"\"<\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

<\/a> \"\"<\/p>\n

 <\/p>\n

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

Resolu\u00e7\u00e3o comentada das quest\u00f5es de F\u00cdSICA da UNICAMP-2018 01- 1. Condu\u00e7\u00e3o O\u00a0calor, devido ao contato entre o c\u00e3o e ch\u00e3o, \u00e9 conduzido do solo para o c\u00e3o, sem que haja deslocamento das part\u00edculas. 2. Evapora\u00e7\u00e3o A l\u00edngua do c\u00e3o libera calor para o meio ambiente pela evapora\u00e7\u00e3o da saliva.\u00a0 3. Convec\u00e7\u00e3o\u00a0 Trata-se da transfer\u00eancia de energia t\u00e9rmica (calor) pela mat\u00e9ria<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":3474,"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-3476","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3476","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=3476"}],"version-history":[{"count":2,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3476\/revisions"}],"predecessor-version":[{"id":3478,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3476\/revisions\/3478"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3474"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=3476"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}