{"id":3292,"date":"2017-10-01T00:17:29","date_gmt":"2017-10-01T00:17:29","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=3292"},"modified":"2024-06-29T23:51:16","modified_gmt":"2024-06-29T23:51:16","slug":"estatica-2014-2013","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/vestibulares-recentes\/mecanica\/estatica-2014-2013\/","title":{"rendered":"Est\u00e1tica \u2013 2014 – 2013"},"content":{"rendered":"

EST\u00c1TICA \u2013 2014 – 2013<\/b><\/span><\/span><\/span><\/p>\n

Est\u00e1tica de um ponto material<\/b><\/span><\/span><\/span><\/p>\n

01-(UNEMAT-MT-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Com a Copa do Mundo de 2014, diversas obras est\u00e3o sendo realizadas, tais como constru\u00e7\u00e3o de novos est\u00e1dios de futebol, novos terminais de transporte p\u00fablico, entre outras. Neste per\u00edodo, \u00e9 comum se ver\u00a0<\/b><\/span><\/span><\/span>trabalhadores sobre vigas e pilares nas constru\u00e7\u00f5es<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Considerando uma\u00a0<\/b><\/span><\/span><\/span>constru\u00e7\u00e3o simples<\/b><\/span><\/span><\/span>, constitu\u00edda de\u00a0<\/b><\/span><\/span><\/span>uma viga na horizontal apoiada nas suas<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

extremidades em duas colunas verticais, denominadas de A e B\u00a0<\/b><\/span><\/span><\/span>e supondo que\u00a0<\/b><\/span><\/span><\/span>um trabalhador se encontra a 1 (um) metro do ponto A e que a viga possua 3 metros de comprimento, assinale a alternativa correta:<\/b><\/span><\/span><\/span><\/p>\n

(A) A carga imposta pela viga \u00e0s colunas \u00e9 igual.<\/b><\/span><\/span><\/span><\/p>\n

(B) A carga imposta pela viga na coluna A \u00e9 o dobro da carga imposta pela viga na coluna B.<\/b><\/span><\/span><\/span><\/p>\n

(C) A carga imposta pela viga na coluna B \u00e9 o dobro da carga imposta pela viga na coluna A.<\/b><\/span><\/span><\/span><\/p>\n

(D) N\u00e3o \u00e9 poss\u00edvel efetuar qualquer rela\u00e7\u00e3o de carga, pois n\u00e3o foi dado o valor da massa do homem.<\/b><\/span><\/span><\/span><\/p>\n

(E) Se o homem continuar movimentando no sentido de B, a carga nesta coluna reduzir\u00e1.<\/b><\/span><\/span><\/span><\/p>\n

02-(MACKENZIE-SP-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Na figura abaixo, a mola M, os fios e a polia possuem in\u00e9rcia desprez\u00edvel e o\u00a0<\/b><\/span><\/span><\/span>coeficiente de atrito <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

est\u00e1tico<\/b><\/span><\/span><\/span> entre o\u00a0<\/b><\/span><\/span><\/span>bloco B, de massa 2,80 kg<\/b><\/span><\/span><\/span>, e o plano inclinado \u00e9\u00a0<\/b><\/span><\/span><\/span>\u03bc = 0,50<\/b><\/span><\/span><\/span>. O sistema ilustrado se encontra em\u00a0<\/b><\/span><\/span><\/span>equil\u00edbrio<\/b><\/span><\/span><\/span>\u00a0e representa o instante em que o bloco B est\u00e1\u00a0<\/b><\/span><\/span><\/span>na imin\u00eancia de entrar em movimento descendente<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Sabendo-se que a\u00a0<\/b><\/span><\/span><\/span>constante el\u00e1stica da mola \u00e9 k = 350 N\/m<\/b><\/span><\/span><\/span>, nesse instante, a\u00a0<\/b><\/span><\/span><\/span>distens\u00e3o da mola M<\/b><\/span><\/span><\/span>, em rela\u00e7\u00e3o ao seu comprimento natural \u00e9 de<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

03-(UNISINOS-RS-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A import\u00e2ncia do atrito<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Este an\u00fancio, da Standard Motor Oil (1932)<\/b><\/span><\/span><\/span>, mostra um exemplo de como o\u00a0<\/b><\/span><\/span><\/span>atrito pode ser positivo:\u00a0<\/b><\/span><\/span><\/span>\u201cO\u00a0<\/b><\/span><\/span><\/span>atrito<\/b><\/span><\/span><\/span>, nos\u00a0<\/b><\/span><\/span><\/span>freios<\/b><\/span><\/span><\/span>, salva at\u00e9 a vi\u00adda humana. Mas,\u00a0<\/b><\/span><\/span><\/span>no motor, \u00e9 fatal<\/b><\/span><\/span><\/span>\u201d. A ilustra\u00ad\u00e7\u00e3o vem acompanhada da explica\u00e7\u00e3o: \u201c<\/b><\/span><\/span><\/span>Bem controlado<\/b><\/span><\/span><\/span>, o\u00a0<\/b><\/span><\/span><\/span>atrito \u00e9 muito \u00fatil<\/b><\/span><\/span><\/span>. Os freios do carro seriam in\u00fateis sem ele.\u00a0<\/b><\/span><\/span><\/span>\u00c9 o atrito dos freios nos tambores dos pneus na estrada que freia o carro<\/b><\/span><\/span><\/span>. Mas, se o atrito \u00e9 um elemento de seguran\u00e7a nos freios, \u00e9\u00a0<\/b><\/span><\/span><\/span>tamb\u00e9m elemento de destrui\u00e7\u00e3o do motor: pode reduzi-lo rapida\u00admente a uma massa inerte\u201d.<\/b><\/span><\/span><\/span><\/p>\n

Um aluno coloca um corpo sobre um plano inclinado\u00a0<\/b><\/span><\/span><\/span>que forma um\u00a0<\/b><\/span><\/span><\/span>\u00e2ngulo \u03b8 = 30\u00ba com a horizontal<\/b><\/span><\/span><\/span>, e o\u00a0<\/b><\/span><\/span><\/span>corpo permanece em repouso.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Neste caso,\u00a0<\/b><\/span><\/span><\/span>o coeficiente de atrito est\u00e1tico m\u00ednimo\u00a0<\/b><\/span><\/span><\/span>entre o\u00a0<\/b><\/span><\/span><\/span>corpo e a superf\u00edcie inclinada\u00a0<\/b><\/span><\/span><\/span>\u00e9 de<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

04-(UEFS-BA-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A figura \u00e9 uma representa\u00e7\u00e3o da vista de cima da sec\u00e7\u00e3o transversal do tronco de uma \u00e1rvore e das<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

for\u00e7as aplicadas no tronco atrav\u00e9s de uma corda tensionada.<\/b><\/span><\/span><\/span><\/p>\n

Nessas condi\u00e7\u00f5es, a intensidade da for\u00e7a resultante aplicada no tronco da \u00e1rvore \u00e9 determinada pela<\/b><\/span><\/span><\/span><\/p>\n

Rela\u00e7\u00e3o<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

05-(UFLA-MG-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considere uma\u00a0<\/b><\/span><\/span><\/span>prateleira,<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>em repouso, de\u00a0<\/b><\/span><\/span><\/span>massa m=2 kg<\/b><\/span><\/span><\/span>, que est\u00e1\u00a0<\/b><\/span><\/span><\/span>dependurada horizontalmente\u00a0<\/b><\/span><\/span><\/span>na parede por meio de um cabo, de massa desprez\u00edvel, como mostra a figura. O cabo est\u00e1\u00a0<\/b><\/span><\/span><\/span>fixo em um dos extremos na parede<\/b><\/span><\/span><\/span>\u00a0e,\u00a0<\/b><\/span><\/span><\/span>no outro extremo, est\u00e1 fixo no meio da prateleira<\/b><\/span><\/span><\/span>. Considere:\u00a0<\/b><\/span><\/span><\/span>g = 10 m\/s<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>;\u00a0<\/b><\/span><\/span><\/span>cos60<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>=1\/2.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A\u00a0<\/b><\/span><\/span><\/span>tens\u00e3o<\/b><\/span><\/span><\/span>\u00a0do cabo \u00e9:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

06-(UFLA-MG-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um lustre formado por tr\u00eas esferas de vidro \u00e9 dependurado no teto, como mostrado na figura. As massas<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

das esferas s\u00e3o 300 g, 200 g e 100 g, respectivamente. Determine a tens\u00e3o em cada uma das cordas, de massa desprez\u00edvel.<\/b><\/span><\/span><\/span><\/p>\n

(A) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0= 6 N, T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0= 3 N e T<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>\u00a0= 1 N <\/b><\/span><\/span><\/span><\/p>\n

(B) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0= 1 N, T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0= 6 N e T<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>\u00a0= 3 N<\/b><\/span><\/span><\/span><\/p>\n

(C) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0= 3 N, T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0= 1 N e T<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>\u00a0= 6 N (<\/b><\/span><\/span><\/span><\/p>\n

D) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0= 1 N, T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0= 3 N e T<\/b><\/span><\/span><\/span>3<\/b><\/span><\/span><\/sub><\/span>\u00a0= 6 N<\/b><\/span><\/span><\/span><\/p>\n

07-(<\/b><\/span><\/span><\/span>UFLA-MG-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Duas crian\u00e7as est\u00e3o sobre uma gangorra de massa desprez\u00edvel<\/b><\/span><\/span><\/span>. A crian\u00e7a da direita\u00a0<\/b><\/span><\/span><\/span>(II) \u00e9 duas vezes mais pesada do que a crian\u00e7a da esquerda (I).\u00a0<\/b><\/span><\/span><\/span>A figura abaixo que representa uma situa\u00e7\u00e3o\u00a0<\/b><\/span><\/span><\/span>de equil\u00edbrio \u00e9<\/b><\/span><\/span><\/span>:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

08-(UFRGS-RS-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Na figura abaixo,\u00a0<\/b><\/span><\/span><\/span>blocos id\u00eanticos\u00a0<\/b><\/span><\/span><\/span>est\u00e3o suspensos por\u00a0<\/b><\/span><\/span><\/span>cordas id\u00eanticas\u00a0<\/b><\/span><\/span><\/span>em tr\u00eas situa\u00e7\u00f5es distintas,\u00a0<\/b><\/span><\/span><\/span>(1), (2) e (3).<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Assinale a alternativa que apresenta as\u00a0<\/b><\/span><\/span><\/span>situa\u00e7\u00f5es na ordem crescente de probabilidade de<\/b><\/span><\/span><\/span><\/p>\n

rompimento das cordas<\/b><\/span><\/span><\/span>. (O sinal de igualdade abaixo indica situa\u00e7\u00f5es com a mesma probabilidade de rompimento.)<\/b><\/span><\/span><\/span><\/p>\n

(A) (3), (2), (1). <\/b><\/span><\/span><\/span><\/p>\n

(B) (3), (2) = (1). <\/b><\/span><\/span><\/span><\/p>\n

(C) (1), (2), (3). <\/b><\/span><\/span><\/span><\/p>\n

(D) (1) = (2), (3). <\/b><\/span><\/span><\/span><\/p>\n

(E) (1) = (2) = (3).<\/b><\/span><\/span><\/span><\/p>\n

09-(UFRR-RR-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

O uso da\u00a0<\/b><\/span><\/span><\/span>f\u00edsica<\/b><\/span><\/span><\/span>\u00a0nos esportes \u00e9 comum e vem crescendo de ano para ano. Vamos considerar que um\u00a0<\/b><\/span><\/span><\/span>atleta\u00a0<\/b><\/span><\/span><\/span>de alto rendimento usou uma\u00a0<\/b><\/span><\/span><\/span>tira de borracha atada ao seu abd\u00f4men<\/b><\/span><\/span><\/span>, conseguindo\u00a0<\/b><\/span><\/span><\/span>alongar\u00a0<\/b><\/span><\/span><\/span>a tira de borracha segundo a tabela:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considerando que a\u00a0<\/b><\/span><\/span><\/span>tira el\u00e1stica obedece a lei de Hooke\u00a0<\/b><\/span><\/span><\/span>e possui\u00a0<\/b><\/span><\/span><\/span>constante el\u00e1stica igual a 60,0N\/m,<\/b><\/span><\/span><\/span> assinale a op\u00e7\u00e3o a qual corresponde a\u00a0<\/b><\/span><\/span><\/span>for\u00e7a exercida pelo atleta na tira, no\u00a0<\/b><\/span><\/span><\/span>dia de menor rendimento<\/b><\/span><\/span><\/span>:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

10-(UFSC-SC-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

S\u00edmbolo de beleza e eleg\u00e2ncia, os\u00a0<\/b><\/span><\/span><\/span>sapatos de salto alto\u00a0<\/b><\/span><\/span><\/span>s\u00e3o usados e desejados por mulheres de<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

todas as idades. Todavia, o seu uso excessivo pode trazer\u00a0<\/b><\/span><\/span><\/span>s\u00e9rios riscos \u00e0 sa\u00fade<\/b><\/span><\/span><\/span>, associados a altera\u00e7\u00f5es de vari\u00e1veis f\u00edsicas importantes para o caminhar, como\u00a0<\/b><\/span><\/span><\/span>les\u00f5es, lordose (curvatura acentuada da coluna para dentro) e deformidades nos p\u00e9s, por exemplo<\/b><\/span><\/span><\/span>. Na figura acima, s\u00e3o apresentados\u00a0<\/b><\/span><\/span><\/span>dois modelos\u00a0<\/b><\/span><\/span><\/span>(A e B)\u00a0<\/b><\/span><\/span><\/span>bastante comuns de sapatos de salto alto, ambos\u00a0<\/b><\/span><\/span><\/span>n\u00famero 34.<\/b><\/span><\/span><\/span><\/p>\n

Assinale a(s)\u00a0<\/b><\/span><\/span><\/span>proposi\u00e7\u00e3o(\u00f5es) CORRETA(S).<\/b><\/span><\/span><\/span><\/p>\n

01. O sapato A permite maior estabilidade no caminhar que o sapato B.<\/b><\/span><\/span><\/span><\/p>\n

02. Com o uso do sapato de salto alto, o centro de gravidade do corpo \u00e9 deslocado para a frente em rela\u00e7\u00e3o a sua posi\u00e7\u00e3o normal (sem o sapato de salto).<\/b><\/span><\/span><\/span><\/p>\n

04. O sapato B permite uma distribui\u00e7\u00e3o mais homog\u00eanea do peso do corpo, nas partes da frente e de tr\u00e1s do p\u00e9, que o sapato A.<\/b><\/span><\/span><\/span><\/p>\n

08. Caminhar com sapato de salto alto pode ser comparado a caminhar descendo um plano inclinado.<\/b><\/span><\/span><\/span><\/p>\n

16. A press\u00e3o sobre o solo em uma caminhada com o sapato A \u00e9 maior que com o sapato B, para<\/b><\/span><\/span><\/span><\/p>\n

uma mesma pessoa.<\/b><\/span><\/span><\/span><\/p>\n

11-(UFV-MG-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um bloco de\u00a0<\/b><\/span><\/span><\/span>massa m<\/b><\/span><\/span><\/span>\u00a0repousa sobre um plano inclinado de um\u00a0<\/b><\/span><\/span><\/span>\u00e2ngulo \u03b8<\/b><\/span><\/span><\/span>. Uma corda inextens\u00edvel passando por uma roldana sem atrito\u00a0<\/b><\/span><\/span><\/span>conecta esse bloco a outro bloco de massa M<\/b><\/span><\/span><\/span>, conforme ilustrado na figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

As massas da corda e da roldana s\u00e3o desprez\u00edveis. Seja\u00a0<\/b><\/span><\/span><\/span>\u03bc<\/b><\/span><\/span><\/span>e<\/b><\/span><\/span><\/sub><\/span>\u00a0o coeficiente de atrito est\u00e1tico e \u03bc<\/b><\/span><\/span><\/span>c<\/b><\/span><\/span><\/sub><\/span>\u00a0o coeficiente de atrito cin\u00e9tico entre o bloco e o plano<\/b><\/span><\/span><\/span>. A alternativa que apresenta CORRETAMENTE o valor da\u00a0<\/b><\/span><\/span><\/span>massa M<\/b><\/span><\/span><\/span>\u00a0para que o\u00a0<\/b><\/span><\/span><\/span>bloco de massa m\u00a0<\/b><\/span><\/span><\/span>des\u00e7a o plano com\u00a0<\/b><\/span><\/span><\/span>velocidade constante\u00a0<\/b><\/span><\/span><\/span>\u00e9<\/b><\/span><\/span><\/span>:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

12-(UnB-014)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A\u00a0<\/b><\/span><\/span><\/span>figura abaixo\u00a0<\/b><\/span><\/span><\/span>mostra um indiv\u00edduo em\u00a0<\/b><\/span><\/span><\/span>repouso<\/b><\/span><\/span><\/span>,\u00a0<\/b><\/span><\/span><\/span>na vertical e apoiado em uma parede.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considerando que\u00a0<\/b><\/span><\/span><\/span>n\u00e3o haja atrito apenas entre o indiv\u00edduo e a parede<\/b><\/span><\/span><\/span>,\u00a0<\/b><\/span><\/span><\/span>desenhe as for\u00e7as que atuam no indiv\u00edduo.<\/b><\/span><\/span><\/span><\/p>\n

Est\u00e1tica de um ponto material<\/b><\/span><\/span><\/span><\/p>\n

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

38-(MACKENZIE-SP-013)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Em uma experi\u00eancia de laborat\u00f3rio, um estudante utilizou os dados do gr\u00e1fico da figura 1, que se referiam \u00e0 intensidade da for\u00e7a aplicada a uma mola helicoidal, em fun\u00e7\u00e3o de sua deforma\u00e7\u00e3o (F=kx). Com esses dados e uma montagem semelhante \u00e0 da figura 2, determinou a massa (m) do corpo suspenso.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Considerando que as massas da mola e dos fios (inextens\u00edveis) s\u00e3o desprez\u00edveis, que\u00a0 g=10m\/s<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>\u00a0e que, na posi\u00e7\u00e3o de equil\u00edbrio, a mola est\u00e1 deformada de 6,4 cm, a massa (m) do corpo suspenso \u00e9<\/b><\/span><\/span><\/span><\/p>\n

a) 12 kg\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b) 8,0 kg\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c) 4,0 kg\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 d) 3,2 kg \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0e) 2,0 kg<\/b><\/span><\/span><\/span><\/p>\n

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

Corpo extenso \u2013 centro de massa e tipos de equil\u00edbrio<\/b><\/span><\/span><\/span><\/p>\n

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

21-(UNIMONTES-MG-013)<\/span><\/span><\/span><\/p>\n

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

Um conjunto de molas sustenta o peso de um carro. Com 2 pessoas de 60kg em seu interior, o carro abaixa 2cm. Com 4<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Com 4 pessoas de 70kg, o carro vai abaixar, aproximadamente: g=10m\/s<\/b><\/span><\/span><\/span>2.<\/b><\/span><\/span><\/sup><\/span><\/p>\n

A) 3,0cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B) 3,5cm. \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\u00a0C) 4,0cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D) 4,7cm.<\/b><\/span><\/span><\/span><\/p>\n

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

22-(UFV-MG-013)<\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

As tr\u00eas figuras abaixo apresentam um mesmo bloco de peso de m\u00f3dulo P suspenso por roldana(s). As roldanas e as<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

cordas ilustradas t\u00eam massas desprez\u00edveis e o equil\u00edbrio est\u00e1tico \u00e9 mantido, em cada caso, por um homem que exerce uma for\u00e7a de m\u00f3dulo F na extremidade livre da corda.<\/b><\/span><\/span><\/span><\/p>\n

Com base nas observa\u00e7\u00f5es das duas primeiras situa\u00e7\u00f5es de equil\u00edbrio, \u00e9 CORRETO afirmar que, na terceira situa\u00e7\u00e3o, o m\u00f3dulo da for\u00e7a F exercida pelo homem \u00e9:<\/b><\/span><\/span><\/span><\/p>\n

a) P\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\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b) P\/2\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\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 c) P\/3\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\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 d) P\/4<\/b><\/span><\/span><\/span><\/p>\n

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

Est\u00e1tica de um corpo extenso \u2013 m\u00e1quinas simples<\/b><\/span><\/span><\/span><\/p>\n

66-(UFV-MG-013)<\/b><\/span><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u201cD\u00ea-me uma alavanca e um ponto de apoio que levantarei o mundo\u201d. Essa c\u00e9lebre frase proferida pelo fil\u00f3sofo grego Arquimedes sintetiza bem a import\u00e2ncia das alavancas, base do funcionamento de in\u00fameros utens\u00edlios, m\u00e1quinas, e at\u00e9 mesmo de membros de nosso corpo.<\/b><\/span><\/span><\/span><\/p>\n

A figura abaixo ilustra uma alavanca, chamada interfixa devido ao fato de o ponto de apoio O se encontrar entre o ponto B, de aplica\u00e7\u00e3o da for\u00e7a potente\u00a0\"\", e o ponto A, de aplica\u00e7\u00e3o da for\u00e7a resistente\u00a0\"\". Sabe-se que, na situa\u00e7\u00e3o de equil\u00edbrio rotacional, o produto do m\u00f3dulo da for\u00e7a potente pela dist\u00e2ncia BO \u00e9 igual ao produto do m\u00f3dulo da for\u00e7a resistente pela dist\u00e2ncia\u00a0\"\".<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um exemplo t\u00edpico desse tipo de alavanca \u00e9 o alicate de cortar fio, ilustrado abaixo.<\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Sendo F o m\u00f3dulo da for\u00e7a potente aplicada ao longo da dire\u00e7\u00e3o assinalada, o correspondente m\u00f3dulo da for\u00e7a resistente do fio ao corte ser\u00e1:<\/b><\/span><\/span><\/span><\/p>\n

a) 2F\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 b) 4F\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\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0c) F\/4\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\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 d) F\/2<\/b><\/span><\/span><\/span><\/p>\n

67-(ENEM-MEC-012)<\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

O mecanismo que permite articular uma porta (de um m\u00f3vel ou de acesso) \u00e9 a dobradi\u00e7a. Normalmente, s\u00e3o necess\u00e1rias<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

duas ou mais dobradi\u00e7as para que a porta seja fixada no m\u00f3vel ou no portal, permanecendo em equil\u00edbrio e podendo ser articulada com facilidade.<\/b><\/span><\/span><\/span><\/p>\n

No plano, o diagrama vetorial das for\u00e7as que as dobradi\u00e7as exercem na porta est\u00e1 representado em<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

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

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

68-(PUC-RJ-013)<\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Deseja-se construir um m\u00f3bile simples, com fios de sustenta\u00e7\u00e3o, hastes e pesinhos de chumbo. Os fios e as hastes t\u00eam peso desprez\u00edvel. A configura\u00e7\u00e3o est\u00e1 demonstrada na figura abaixo.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

O pesinho de chumbo quadrado tem massa 30 g, e os pesinhos triangulares t\u00eam massa 10 g.<\/b><\/span><\/span><\/span><\/p>\n

Para que a haste maior possa ficar horizontal, qual deve \u00a0ser a dist\u00e2ncia horizontal x, em cent\u00edmetros?<\/b><\/span><\/span><\/span><\/p>\n

(A) 45\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (B) 15\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (C) 20\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\u00a0 (D) 10\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (E) 30<\/b><\/span><\/span><\/span><\/p>\n

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

69-(ESPCEX-013)<\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Uma barra homog\u00eanea de peso igual a 50 N est\u00e1 em repouso na horizontal. Ela est\u00e1 apoiada em seus extremos nos pontos A e B, que est\u00e3o distanciados de 2 m. Uma esfera Q de peso 80 N \u00e9 colocada sobre a barra, a uma dist\u00e2ncia de 40 cm do ponto A, conforme representado no desenho abaixo:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A intensidade da for\u00e7a de rea\u00e7\u00e3o do apoio sobre a barra no ponto B \u00e9 de<\/b><\/span><\/span><\/span><\/p>\n

a)\u00a0 32 N \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0b)\u00a0 41 N \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0c)\u00a0 75 N \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0d)\u00a0 82 N \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0e)\u00a0 130 N<\/b><\/span><\/span><\/span><\/p>\n

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

70-(UERJ-RJ-013)<\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um homem de massa igual a 80 kg est\u00e1 em repouso e em equil\u00edbrio sobre uma prancha r\u00edgida de 2,0 m de<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

comprimento, cuja massa \u00e9 muito menor que a do homem.<\/b><\/span><\/span><\/span><\/p>\n

A prancha est\u00e1 posicionada horizontalmente sobre dois apoios, A e B, em suas extremidades, e o homem est\u00e1 a 0,2 m da extremidade apoiada em A.<\/b><\/span><\/span><\/span><\/p>\n

A intensidade da for\u00e7a, em newtons, que a prancha exerce sobre o apoio A equivale a (adote g=10m\/s<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>):<\/b><\/span><\/span><\/span><\/p>\n

(A) 200\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\u00a0\u00a0 (B) 360\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\u00a0\u00a0\u00a0\u00a0\u00a0 (C) 400\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\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (D) 720<\/b><\/span><\/span><\/span>\u00a0<\/span><\/span><\/span><\/p>\n

71-(ESCOLA NAVAL-012-013)<\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A viga inclinada de\u00a060<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>\u00a0mostrada na figura repousa sobre dois apoios\u00a0A\u00a0e\u00a0D. Nos pontos\u00a0C\u00a0e\u00a0E, dois <\/b><\/span><\/span><\/span><\/p>\n

\"Est\u00e1tica\"<\/p>\n

blocos de massa\u00a08,00kg\u00a0est\u00e3o pendurados por meio de um fio ideal. Uma for\u00e7a de\u00a0F=30N\u00a0traciona um fio ideal preso \u00e0 viga no ponto\u00a0B. Desprezando o peso da viga e o atrito no apoio\u00a0D, a rea\u00e7\u00e3o normal que o apoio\u00a0D\u00a0exerce na viga, em newtons, \u00e9 igual a
\na) 30,0\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\u00a0b) 50,0\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\u00a0c) 70,0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0d) 90,0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0e) 110<\/b><\/span><\/span><\/span><\/p>\n

Confira as resolu\u00e7\u00f5es comentadas<\/span><\/a><\/h3>\n

 <\/p>\n

Clique aqui para ver sobre o tema!<\/a><\/p>\n

Confira as v\u00eddeo aulas!<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

EST\u00c1TICA \u2013 2014 – 2013 Est\u00e1tica de um ponto material 01-(UNEMAT-MT-014) Com a Copa do Mundo de 2014, diversas obras est\u00e3o sendo realizadas, tais como constru\u00e7\u00e3o de novos est\u00e1dios de futebol, novos terminais de transporte p\u00fablico, entre outras. Neste per\u00edodo, \u00e9 comum se ver\u00a0trabalhadores sobre vigas e pilares nas constru\u00e7\u00f5es. Considerando uma\u00a0constru\u00e7\u00e3o simples, constitu\u00edda de\u00a0uma viga na horizontal apoiada nas<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":3123,"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-3292","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3292","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=3292"}],"version-history":[{"count":5,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3292\/revisions"}],"predecessor-version":[{"id":9887,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3292\/revisions\/9887"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3123"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=3292"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}