{"id":3684,"date":"2018-02-13T16:29:33","date_gmt":"2018-02-13T16:29:33","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=3684"},"modified":"2024-08-20T18:31:02","modified_gmt":"2024-08-20T18:31:02","slug":"estatica-de-um-ponto-material","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/enem\/estatica-de-um-ponto-material\/","title":{"rendered":"Est\u00e1tica de um Ponto Material"},"content":{"rendered":"

Est\u00e1tica de um Ponto Material<\/b><\/span><\/span><\/span><\/p>\n

Exerc\u00edcios com caracter\u00edsticas de ENEM<\/b><\/span><\/span><\/span><\/p>\n

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

01-(UNIFOR-CE)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Com 6 peda\u00e7os iguais de corda e tr\u00eas corpos de mesma massa e mesmo formato, um estudante fez as montagens representadas abaixo.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Nos peda\u00e7os de corda a intensidade da for\u00e7a de tra\u00e7\u00e3o \u00e9<\/b><\/span><\/span><\/span><\/p>\n

a) a mesma nas montagens 1, 2 e 3.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

b) maior na montagem 3 que na 2.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

c) maior na montagem 2 que na 3.<\/b><\/span><\/span><\/span><\/p>\n

d) a mesma nas montagens 2 e 3 e menor que na 1.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

e) a mesma nas montagens 2 e 3 e maior que na 1.<\/b><\/span><\/span><\/span><\/p>\n

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

02-(CFT-CE)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um quadro de massa m = 6,0 kg se encontra em equil\u00edbrio pendurado ao teto pelos fios 1 e 2, que fazem com a horizontal os \u00e2ngulos\u00a0 \u03b8<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>\u00a0= 60\u00b0 e\u00a0 \u03b8<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>\u00a0= 30\u00b0, conforme a figura.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Adotando g=10m\/s<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sup><\/span>, calcule as tra\u00e7\u00f5es nos fios 1 e 2.<\/b><\/span><\/span><\/span><\/p>\n

Dados: sen30\u00b0 = cos60\u00b0 = 1\/2\u00a0 —\u00a0 cos30\u00b0 = sen60\u00b0 =\u00a0 (\u221a3)\/2<\/b><\/span><\/span><\/span><\/p>\n

a) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=20\u221a3N e T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=20N\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

b) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=30\u221a3N e T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=30N\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

c) ) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=30\u221a2N e T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=30\u221a3N\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

d) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=10N e T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=30N<\/b><\/span><\/span><\/span><\/p>\n

e) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=30N e T<\/b><\/span><\/span><\/span>2<\/b><\/span><\/span><\/sub><\/span>=10N<\/b><\/span><\/span><\/span><\/p>\n

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

03-(UNICAMP-SP)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Uma das modalidades de gin\u00e1stica ol\u00edmpica \u00e9 a das argolas. Nessa modalidade, os m\u00fasculos mais solicitados s\u00e3o os dos bra\u00e7os, que suportam as cargas horizontais, e os da regi\u00e3o dorsal, que suportam os esfor\u00e7os verticais. Considerando um atleta cuja massa \u00e9 de 60 kg e sendo os comprimentos indicados na figura H = 3,0 m; L = 1,5 m e d = 0,5 m, as tens\u00f5es verticais em cada <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

corda na figura 1 e as componentes horizontais das tens\u00f5es em cada corda na figura 2, s\u00e3o respectivamente:<\/b><\/span><\/span><\/span><\/p>\n

\u00a0a) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=200N e T<\/b><\/span><\/span><\/span>x<\/b><\/span><\/span><\/sub><\/span>=60N\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

b) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=30N e T<\/b><\/span><\/span><\/span>x<\/b><\/span><\/span><\/sub><\/span>=5N\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

c) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=125N e T<\/b><\/span><\/span><\/span>x<\/b><\/span><\/span><\/sub><\/span>=250N\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

d) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=100N e T<\/b><\/span><\/span><\/span>x<\/b><\/span><\/span><\/sub><\/span>=110N\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

e) T<\/b><\/span><\/span><\/span>1<\/b><\/span><\/span><\/sub><\/span>=300N e T<\/b><\/span><\/span><\/span>x<\/b><\/span><\/span><\/sub><\/span>=50N<\/b><\/span><\/span><\/span><\/p>\n

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

04-(UEL-PR)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

As placas I, II, III, IV e V est\u00e3o submetidas a for\u00e7as cujas dire\u00e7\u00f5es est\u00e3o indicadas no esquema e suas respectivas intensidades devem ser ajustadas para que a resultante seja nula e as placas fiquem em equil\u00edbrio est\u00e1tico.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Em uma das placas, o acerto das intensidades das for\u00e7as para obter o equil\u00edbrio est\u00e1tico \u00e9 imposs\u00edvel. Essa placa \u00e9 a<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

05-(UFPEL-RS)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Para garantir o sono tranquilo de Chico Bento, Rosinha segura a rede, exercendo sobre ela uma for\u00e7a inclinada de 37\u00ba em rela\u00e7\u00e3o \u00e0 horizontal, como mostra a figura abaixo.<\/b><\/span><\/span><\/span><\/p>\n

Desprezando o peso da rede e sabendo que Chico Bento pesa 280 N, observamos que Rosinha ter\u00e1 <\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

grande dificuldade para permanecer segurando a rede, pois precisa exercer sobre ela uma for\u00e7a de:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

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

06-(FUVEST-SP)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Um mesmo pacote pode ser carregado com cordas amarradas\u00a0 de v\u00e1rias maneiras. A situa\u00e7\u00e3o, dentre as apresentadas, em que as cordas est\u00e3o sujeitas \u00e0 maior tens\u00e3o \u00e9:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

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

\u00a0<\/span>07-(UFPR-PR)<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Uma corrente composta por cinco elos est\u00e1 presa ao teto por meio de um barbante, conforme mostra a figura. \u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

A massa de cada elo \u00e9 de 200 g. Os m\u00f3dulos de todas as for\u00e7a que est\u00e3o atuando no terceiro elo s\u00e3o, respectivamente:<\/b><\/span><\/span><\/span><\/p>\n

a) P=2 N; F<\/b><\/span><\/span><\/span>43<\/b><\/span><\/span><\/sub><\/span>=4 N e F<\/b><\/span><\/span><\/span>23<\/b><\/span><\/span><\/sub><\/span>=5 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\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

b) P=2 N; F<\/b><\/span><\/span><\/span>43<\/b><\/span><\/span><\/sub><\/span>=4 N e F<\/b><\/span><\/span><\/span>23<\/b><\/span><\/span><\/sub><\/span>=6 N\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n

c) P=4 N; F<\/b><\/span><\/span><\/span>43<\/b><\/span><\/span><\/sub><\/span>=4 N e F<\/b><\/span><\/span><\/span>23<\/b><\/span><\/span><\/sub><\/span>=6 N<\/b><\/span><\/span><\/span><\/p>\n

d) P=2 N; F<\/b><\/span><\/span><\/span>43<\/b><\/span><\/span><\/sub><\/span>=5 N e F<\/b><\/span><\/span><\/span>23<\/b><\/span><\/span><\/sub><\/span>=5 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\u00a0 \u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n

e) P=2 N; F<\/b><\/span><\/span><\/span>43<\/b><\/span><\/span><\/sub><\/span>=4 N e F<\/b><\/span><\/span><\/span>23<\/b><\/span><\/span><\/sub><\/span>=7N<\/b><\/span><\/span><\/span><\/p>\n

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

08-(PUC-RS)\u00a0<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

Dois oper\u00e1rios suspendem um balde por meio de cordas, conforme mostra o esquema a seguir.<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

\u00a0S\u00e3o dados: sen30\u00ba = cos60\u00ba=1\/2 e sen60<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>=cos30<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>=\u221a3\/2<\/b><\/span><\/span><\/span><\/p>\n

Sabe-se que o balde, com seu conte\u00fado, t\u00eam peso 50N, e que o \u00e2ngulo formado entre as partes da corda no ponto de suspens\u00e3o \u00e9 60<\/b><\/span><\/span><\/span>o<\/b><\/span><\/span><\/sup><\/span>. A corda pode ser considerada como ideal (inextens\u00edvel e de massa desprez\u00edvel).<\/b><\/span><\/span><\/span><\/p>\n

Quando o balde est\u00e1 suspenso no ar, em equil\u00edbrio, a for\u00e7a exercida por um oper\u00e1rio, medida em newtons, vale:<\/b><\/span><\/span><\/span><\/p>\n

\"\"<\/p>\n

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

Confira a resolu\u00e7\u00e3o comentada<\/a><\/span><\/h3>\n","protected":false},"excerpt":{"rendered":"

Est\u00e1tica de um Ponto Material Exerc\u00edcios com caracter\u00edsticas de ENEM \u00a0 01-(UNIFOR-CE) Com 6 peda\u00e7os iguais de corda e tr\u00eas corpos de mesma massa e mesmo formato, um estudante fez as montagens representadas abaixo. Nos peda\u00e7os de corda a intensidade da for\u00e7a de tra\u00e7\u00e3o \u00e9 a) a mesma nas montagens 1, 2 e 3.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 b) maior na montagem 3 que<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":3575,"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-3684","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3684","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=3684"}],"version-history":[{"count":3,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3684\/revisions"}],"predecessor-version":[{"id":9798,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3684\/revisions\/9798"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3575"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=3684"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}