{"id":2932,"date":"2017-05-16T15:07:36","date_gmt":"2017-05-16T15:07:36","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=2932"},"modified":"2024-09-03T16:39:16","modified_gmt":"2024-09-03T16:39:16","slug":"resolucao-comentada-das-questoes-de-fisica-do-vestibular-da-uece-ce-2017","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/universidades-2017\/uece-2017\/resolucao-comentada-das-questoes-de-fisica-do-vestibular-da-uece-ce-2017\/","title":{"rendered":"Resolu\u00e7\u00e3o comentada das quest\u00f5es de F\u00cdSICA do vestibular da UECE-CE- 2017"},"content":{"rendered":"

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

UECE-CE- 2017<\/span><\/span><\/span><\/p>\n

01<\/b><\/span><\/span><\/span>– <\/span><\/span>A express\u00e3o do <\/b><\/span><\/span><\/span>momento linear (quantidade de movimento) <\/b><\/span><\/span><\/span>tem <\/b><\/span><\/span><\/span>intensidade<\/b><\/span><\/span><\/span> \"\" <\/b><\/span><\/span><\/span>Q = m.V <\/b><\/span><\/span><\/span>= 1.2 \"\"<\/b><\/span><\/span><\/span>Q = 2 kg.m\/s<\/b><\/span><\/span><\/span><\/p>\n

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

02<\/b><\/span><\/span><\/span>– <\/span><\/span>No in\u00edcio, <\/b><\/span><\/span><\/span>quando <\/b><\/span><\/span><\/span>ele sobe acelerando, <\/b><\/span><\/span><\/span>a <\/b><\/span><\/span><\/span>for\u00e7a exercida pelo cabo <\/b><\/span><\/span><\/span>na cabine tem <\/b><\/span><\/span><\/span>intensidade maior que a do peso, pois a for\u00e7a resultante \u00e9 para cima F<\/b><\/span><\/span><\/span>I<\/b><\/span><\/span><\/sub><\/span> > P.<\/b><\/span><\/span><\/span><\/p>\n

No final, antes da parada, <\/b><\/span><\/span><\/span>ele est\u00e1 <\/b><\/span><\/span><\/span>freando e desacelerando com a for\u00e7a resultante sendo para cima <\/b><\/span><\/span><\/span>at\u00e9 <\/b><\/span><\/span><\/span>se tornar nula <\/b><\/span><\/span><\/span>quando <\/b><\/span><\/span><\/span>F<\/b><\/span><\/span><\/span>F<\/b><\/span><\/span><\/sub><\/span> = P <\/b><\/span><\/span><\/span>(ele para) <\/b><\/span><\/span><\/span><\/p>\n

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

03- <\/b><\/span><\/span><\/span>Como as <\/b><\/span><\/span><\/span>tr\u00eas pe\u00e7as possuem o mesmo material <\/b><\/span><\/span><\/span>(mesma massa espec\u00edfica) e <\/b><\/span><\/span><\/span>mesmo volume<\/b><\/span><\/span><\/span>, a <\/b><\/span><\/span><\/span>massa dos tr\u00eas \u00e9 a mesma, pois \"\"= \"\"<\/b><\/span><\/span><\/span> \"\" <\/b><\/span><\/span><\/span>m =<\/b><\/span><\/span><\/span> \"\"<\/b><\/span><\/span><\/span><\/p>\n

Se a <\/b><\/span><\/span><\/span>massa m \u00e9 a mesma, <\/b><\/span><\/span><\/span>o <\/b><\/span><\/span><\/span>peso P<\/b><\/span><\/span><\/span> tamb\u00e9m ser\u00e1 <\/b><\/span><\/span><\/span>o mesmo, <\/b><\/span><\/span><\/span>pois <\/b><\/span><\/span><\/span>P = m.g <\/b><\/span><\/span><\/span>e, ent\u00e3o a <\/b><\/span><\/span><\/span>for\u00e7a exercida por cada um deles sobre a mesa \u00e9 a mesma (peso de cada um).<\/b><\/span><\/span><\/span><\/p>\n

Sendo a <\/b><\/span><\/span><\/span>press\u00e3o P = \"\"<\/b><\/span><\/span><\/span> \"\"<\/b><\/span><\/span><\/span> a <\/b><\/span><\/span><\/span>press\u00e3o P \u00e9 inversamente proporcional \u00e0 \u00e1rea de contato <\/b><\/span><\/span><\/span>e, assim, <\/b><\/span><\/span><\/span>menor \u00e1rea, maior press\u00e3o.<\/b><\/span><\/span><\/span><\/p>\n

Veja <\/b><\/span><\/span><\/span>na figura <\/b><\/span><\/span><\/span>que a <\/b><\/span><\/span><\/span>alternativa correta \u00e9 a D.<\/b><\/span><\/span><\/span><\/p>\n

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

<\/a>04- <\/b><\/span><\/span><\/span>Pilhas iguais <\/b><\/span><\/span><\/span>associadas em <\/b><\/span><\/span><\/span>paralelo<\/b><\/span><\/span><\/span> possuem a <\/b><\/span><\/span><\/span>mesma fem U = E = 1,5 V <\/b><\/span><\/span><\/span>e conectadas a <\/b><\/span><\/span><\/span>R = <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

15\u2126<\/b><\/span><\/span><\/span> fornecem uma <\/b><\/span><\/span><\/span>corrente el\u00e9trica de R = \"\"<\/b><\/span><\/span><\/span> \"\" <\/b><\/span><\/span><\/span>15 = \"\" \"\" i = \"\" \"\" <\/b><\/span><\/span><\/span>i = 0,1 A.<\/b><\/span><\/span><\/span><\/p>\n

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

05- <\/b><\/span><\/span><\/span>A <\/b><\/span><\/span><\/span>express\u00e3o da frequ\u00eancia de oscila\u00e7\u00e3o de um sistema massa mola <\/b><\/span><\/span><\/span>\u00e9 <\/b><\/span><\/span><\/span>f = \"\"<\/b><\/span><\/span><\/span>x\"\"<\/b><\/span><\/span><\/span> <\/b>(se voc\u00ea n\u00e3o domina a teoria, a demonstra\u00e7\u00e3o est\u00e1 em fisicaevestibular.com.br \u2013 mec\u00e2nica \u2013 din\u00e2mica \u2013 MHS \u2013 sistema massa-mola).<\/b><\/span><\/span><\/span><\/p>\n

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

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

Caracter\u00edsticas da associa\u00e7\u00e3o s\u00e9rie<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"\u00a0<\/span>Todos<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>os resistores s\u00e3o<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>ligados um em seguida ao outro.\u00a0<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"\u00a0<\/span>A<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>intensidade da\u00a0corrente el\u00e9trica i \u00e9 a mesma em todos os resistores<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"\u00a0A<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>tens\u00e3o U nos terminais da associa\u00e7\u00e3o<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>(entre A e B) \u00e9<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>igual \u00e0 soma das tens\u00f5es<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>em<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>cada resistor, ou seja,\u00a0U= U<\/b><\/span><\/span>1<\/b><\/span><\/sub><\/span>+ U<\/b><\/span><\/span>2<\/b><\/span><\/sub><\/span>\u00a0+ U<\/b><\/span><\/span>3<\/b><\/span><\/sub><\/span><\/span><\/span><\/p>\n

\"\"\u00a0A<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>resist\u00eancia equivalente (R<\/b><\/span><\/span>eq<\/b><\/span><\/sub><\/span>) \u00e9 igual \u00e0 soma das <\/b><\/span><\/span>resist\u00eancias parciais\u00a0<\/b><\/span><\/span>\u00a0\"\"<\/b><\/span><\/span>\u00a0\u00a0<\/b><\/span><\/span>R<\/b><\/span><\/span>eq<\/b><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span>= R<\/b><\/span><\/span>1<\/b><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span>+ R<\/b><\/span><\/span>2<\/b><\/span><\/sub><\/span>\u00a0<\/b><\/span><\/span>+ R<\/b><\/span><\/span>3<\/b><\/span><\/sub><\/span><\/span><\/span><\/p>\n

Como a <\/b><\/span><\/span><\/span>intensidade da corrente el\u00e9trica \u00e9 a mesma <\/b><\/span><\/span><\/span>em<\/b><\/span><\/span><\/span> cada resistor<\/b><\/span><\/span><\/span>, pela<\/b><\/span><\/span><\/span> lei de Ohm R = \"\" , <\/b><\/span><\/span><\/span>voc\u00ea<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

observa que <\/b><\/span><\/span><\/span>a tens\u00e3o U \u00e9 diretamente proporcional \u00e0 R.<\/b><\/span><\/span><\/span><\/p>\n

Assim,<\/b><\/span><\/span><\/span> maior R, maior tens\u00e3o U.<\/b><\/span><\/span><\/span><\/p>\n

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

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

Veja as <\/b><\/span><\/span><\/span>caracter\u00edsticas <\/b><\/span><\/span><\/span>das <\/b><\/span><\/span><\/span>associa\u00e7\u00f5es s\u00e9rie e paralelo <\/b><\/span><\/span><\/span>de molas abaixo:<\/b><\/span><\/span><\/span><\/p>\n

Associa\u00e7\u00e3o em paralelo<\/b><\/span><\/span><\/span><\/span><\/p>\n

Nesse caso a<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>deforma\u00e7\u00e3o<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>x<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>sofrida por<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>cada uma das molas \u00e9 a mesma.<\/b><\/span><\/span><\/span><\/span><\/p>\n

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

Associa\u00e7\u00e3o em s\u00e9rie<\/b><\/span><\/span><\/span><\/span><\/p>\n

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

Nesse caso as<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>molas 1 e 2 est\u00e3o sujeitas \u00e0 mesma for\u00e7a F<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>e<\/b><\/span><\/span>\u00a0<\/b><\/span><\/span>sofrem deforma\u00e7\u00f5es diferentes<\/b><\/span><\/span>\u00a0<\/b><\/span>x1\u00a0e x2.<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Observe que a <\/b><\/span><\/span><\/span>constante el\u00e1stica (coeficiente el\u00e1stico) <\/b><\/span><\/span><\/span>da <\/b><\/span><\/span><\/span>associa\u00e7\u00e3o paralelo \u00e9 maior do que a da s\u00e9rie.<\/b><\/span><\/span><\/span><\/p>\n

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

08- <\/b><\/span><\/span><\/span>Sendo, pelo enunciado a <\/b><\/span><\/span><\/span>for\u00e7a que age sobre cada carro constante e igual \"\"<\/b><\/span><\/span><\/span> <\/b>F<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> = F<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span> \"\"<\/b><\/span><\/span><\/span> <\/b> <\/b><\/p>\n

\"\"<\/p>\n

m<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>.a<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> = m<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>.a<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span> \"\"<\/b><\/span><\/span><\/span> <\/b>a<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> = m<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>.a<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\/m<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> \"\"<\/b><\/span><\/span><\/span> como <\/b><\/span><\/span><\/span>m<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span> e a<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span> <\/b>s\u00e3o <\/b><\/span><\/span><\/span>constantes, a medida que m<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> vai diminuindo <\/b><\/span><\/span><\/span>(perdendo areia), <\/b><\/span><\/span><\/span>a<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span> vai aumentando <\/b><\/span><\/span><\/span>(inversamente proporcionais) \"\" <\/b><\/span><\/span><\/span>a<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> > a<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Para os <\/b><\/span><\/span><\/span>dois carros V = V<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sub><\/span> + at \"\"<\/b><\/span><\/span><\/span> V = 0 + at \"\" <\/b><\/span><\/span><\/span>V = at.<\/b><\/span><\/span><\/span><\/p>\n

V<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> = a<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>.t \"\" V<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span> = a<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>.t<\/b><\/span><\/span><\/span> \"\" <\/b><\/span><\/span><\/sub><\/span>como <\/b><\/span><\/span><\/span>t \u00e9 o mesmo <\/b><\/span><\/span><\/span>e <\/b><\/span><\/span><\/span>a<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> > a<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span> \"\"<\/b><\/span><\/span><\/span> <\/b>V<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span> > V<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

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

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

\"\"<\/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 do vestibular da UECE-CE- 2017 01– A express\u00e3o do momento linear (quantidade de movimento) tem intensidade Q = m.V = 1.2 Q = 2 kg.m\/s R- A 02– No in\u00edcio, quando ele sobe acelerando, a for\u00e7a exercida pelo cabo na cabine tem intensidade maior que a do peso, pois a for\u00e7a resultante \u00e9 para<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2930,"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-2932","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2932","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=2932"}],"version-history":[{"count":1,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2932\/revisions"}],"predecessor-version":[{"id":2933,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2932\/revisions\/2933"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/2930"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=2932"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}