{"id":3627,"date":"2018-02-13T12:49:42","date_gmt":"2018-02-13T12:49:42","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=3627"},"modified":"2024-11-12T13:14:53","modified_gmt":"2024-11-12T13:14:53","slug":"aplicacoes-das-leis-de-newton-com-atrito","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/enem\/aplicacoes-das-leis-de-newton-com-atrito\/","title":{"rendered":"Aplica\u00e7\u00f5es das leis de Newton com atrito"},"content":{"rendered":"<p align=\"CENTER\"><span style=\"color: #c00000;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>Aplica\u00e7\u00f5es das leis de Newton com atrito<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>Exerc\u00edcios com caracter\u00edsticas de ENEM<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>01-(FUVEST-SP)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img fetchpriority=\"high\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_dafa94dc.jpg\" alt=\"\" width=\"780\" height=\"133\" name=\"Imagem 1\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>O gr\u00e1fico a seguir descreve o deslocamento vertical y, para baixo, de um surfista a\u00e9reo de massa igual a 75 kg, em fun\u00e7\u00e3o do tempo t.<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_2746f80.jpg\" alt=\"\" width=\"645\" height=\"205\" name=\"Imagem 2\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>A origem y = 0, em t = 0, \u00e9 tomada na altura do salto. Nesse movimento, a for\u00e7a R de resist\u00eancia do ar \u00e9 proporcional ao quadrado da velocidade v do surfista (R = kv<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>), onde k \u00e9 uma constante que depende principalmente da densidade do ar e da geometria do surfista). <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>A velocidade inicial do surfista \u00e9 nula; cresce com o tempo, por aproximadamente 10 s, e tende para uma velocidade constante denominada velocidade limite (V<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sub><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>L<\/b><\/span><\/span><\/sub><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>).<br \/>\nOs valores da velocidade limite V<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sub><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>L<\/b><\/span><\/span><\/sub><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\u00a0e da constante k s\u00e3o, no SI, respectivamente:<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>a) 50 m\/s e 0,3 N.s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\/m<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>b) 60 m\/s e 3 N.s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\/m<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>c) 5 m\/s e 0,6 N.s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\/m<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>d) 40 m\/s e 0,5 N.s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\/m<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\u00a0\u00a0\u00a0\u00a0\u00a0 <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>e) 50 m\/s e 0,6 N.s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\/m<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>02-(UEG-GO)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_97303d26.jpg\" alt=\"\" width=\"780\" height=\"131\" name=\"Imagem 3\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Entre os poucos animais que desenvolveram o \u201cp\u00e1ra-quedismo\u201d est\u00e1 o sapo voador de Born\u00e9u \u2013 Rhacophorus dulitensis, apresentado na figura a seguir.<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_c4fc7d36.jpg\" alt=\"\" width=\"708\" height=\"224\" name=\"Imagem 4\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Na ilustra\u00e7\u00e3o,\u00a0<img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_46bc466a.jpg\" alt=\"\" width=\"12\" height=\"20\" name=\"Imagem 5\" align=\"BOTTOM\" border=\"0\" \/>\u00a0e\u00a0<img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_ea694baf.jpg\" alt=\"\" width=\"26\" height=\"18\" name=\"Imagem 6\" align=\"BOTTOM\" border=\"0\" \/>\u00a0\u00a0s\u00e3o, respectivamente, a for\u00e7a de resist\u00eancia do ar e a for\u00e7a peso.\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Considerando que esse animal tenha se atirado do alto de uma \u00e1rvore em dire\u00e7\u00e3o ao solo, o seu p\u00e1ra-quedas ser\u00e1 utilizado e, durante sua queda,<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>a) as suas membranas interdigitais nas patas favorecem o aumento da for\u00e7a de resist\u00eancia do ar, haja vista que elas aumentam a \u00e1rea de contato com o ar.\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>b) a resultante das for\u00e7as que atuam sobre ele tender\u00e1 a se tornar nula, levando-o, necessariamente, ao repouso no ar.\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>c) a sua velocidade tender\u00e1 a um valor limite, chamada de velocidade terminal, independentemente da resist\u00eancia do ar.\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>d) a sua acelera\u00e7\u00e3o ser\u00e1 nula em todo o percurso, independentemente da resist\u00eancia do ar.\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>e) durante sua queda, a for\u00e7a de resist\u00eancia do ar (vertical e para cima) vai aumentando at\u00e9 superar a for\u00e7a peso (vertical e para baixo), ap\u00f3s ent\u00e3o, ele come\u00e7a a subir.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>03-(UNESP-SP)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_10cc02cf.jpg\" alt=\"\" width=\"780\" height=\"133\" name=\"Imagem 7\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Um bloco de massa 5,0kg est\u00e1 apoiado sobre um plano inclinado de 30\u00b0 em rela\u00e7\u00e3o a um plano horizontal.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Se uma for\u00e7a constante, de intensidade F, paralela ao plano inclinado e dirigida para cima, \u00e9 aplicada ao bloco, este adquire uma acelera\u00e7\u00e3o para baixo e sua velocidade escalar \u00e9 dada por v = 2,0t (SI), (fig.1).<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Se uma for\u00e7a constante, de mesma intensidade F, paralela ao plano inclinado e dirigida para baixo for aplicada ao bloco, este adquire uma acelera\u00e7\u00e3o para baixo e sua velocidade escalar \u00e9 dada por v&#8217; = 3,0t (SI), (fig. 2).<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_a11967c6.jpg\" alt=\"\" width=\"625\" height=\"184\" name=\"Imagem 8\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Os valores de F e do coeficiente de atrito de deslizamento s\u00e3o, respectivamente: (adote g=10m\/s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>)<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>04-(UFJF-MG)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_a7e70dd3.jpg\" alt=\"\" width=\"777\" height=\"129\" name=\"Imagem 9\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Um caminh\u00e3o \u00e9 carregado com duas caixas\u00a0 de madeira, de massas iguais a 500kg, conforme mostra a figura.<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_81ad4ecf.jpg\" alt=\"\" width=\"524\" height=\"161\" name=\"Imagem 10\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>O caminh\u00e3o \u00e9 ent\u00e3o posto em movimento numa estrada reta e plana, acelerando at\u00e9 adquirir uma velocidade de 108 km\/h e depois \u00e9 freado at\u00e9 parar, conforme mostra o gr\u00e1fico. (g=10m\/s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>).<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_36724a5b.jpg\" alt=\"\" width=\"513\" height=\"199\" name=\"Imagem 11\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>O coeficiente de atrito est\u00e1tico entre as caixas e a carroceria do caminh\u00e3o \u00e9 m=0,1. Qual das figuras abaixo melhor representa a disposi\u00e7\u00e3o das caixas sobre a carroceria no final do movimento?<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_76cb9844.jpg\" alt=\"\" width=\"784\" height=\"119\" name=\"Imagem 12\" align=\"BOTTOM\" border=\"0\" \/><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>05-(UFRRJ-RJ)<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_fe08e66e.jpg\" alt=\"\" width=\"774\" height=\"129\" name=\"Imagem 13\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Dois carros de corrida s\u00e3o projetados de forma a aumentar o atrito entre os pneus e a pista. Os <\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_e9e36954.jpg\" alt=\"\" width=\"560\" height=\"171\" name=\"Imagem 14\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>projetos s\u00e3o id\u00eanticos, exceto que\u00a0num deles os pneus s\u00e3o mais largos e no outro h\u00e1 um aerof\u00f3lio. Nessas condi\u00e7\u00f5es podemos dizer que<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>a) em ambos os projetos, o atrito ser\u00e1 aumentado em rela\u00e7\u00e3o ao projeto original.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>b) em ambos os projetos, o atrito ser\u00e1 diminu\u00eddo em rela\u00e7\u00e3o ao projeto original.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>c) o atrito ser\u00e1 maior no carro com aerof\u00f3lio.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>d) o atrito ser\u00e1 maior no carro com pneus mais largos.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>e) nenhum dos projetos alterar\u00e1 o atrito.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>06-(UFAL-AL)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_5d88b1bc.jpg\" alt=\"\" width=\"783\" height=\"140\" name=\"Imagem 15\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>O bloco da figura possui peso P e se encontra na imin\u00eancia de movimento sob a a\u00e7\u00e3o de uma for\u00e7a de m\u00f3dulo constante F e dire\u00e7\u00e3o perpendicular \u00e0 parede vertical. Se o coeficiente de atrito est\u00e1tico entre a parede e o bloco \u00e9 menor que 1, assinale a rela\u00e7\u00e3o correta entre P e F.<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_242f7f2.jpg\" alt=\"\" width=\"428\" height=\"214\" name=\"Imagem 16\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><span lang=\"en-US\"><b>a) 0 &lt; P &lt; F\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0b) F &lt; P &lt; 2F\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0c) 0 &lt; F &lt; P\/2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0d) P\/2 &lt; F &lt; P\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0e) 0 &lt; F &lt; P<\/b><\/span><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>07-(UERJ-RJ)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_589c1828.jpg\" alt=\"\" width=\"783\" height=\"132\" name=\"Imagem 17\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Uma pessoa de massa igual a 80 kg encontra-se em repouso, em p\u00e9 sobre o solo, pressionando perpendicularmente uma parede com uma for\u00e7a de magnitude igual a 120 N, como mostra a ilustra\u00e7\u00e3o a seguir.<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_41098c90.jpg\" alt=\"\" width=\"293\" height=\"216\" name=\"Imagem 18\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>A melhor representa\u00e7\u00e3o gr\u00e1fica para as distintas for\u00e7as externas que atuam sobre a pessoa est\u00e1 indicada em:<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_e727673a.jpg\" alt=\"\" width=\"781\" height=\"140\" name=\"Imagem 19\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>08-(UERJ-RJ)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_26a29768.jpg\" alt=\"\" width=\"566\" height=\"125\" name=\"Imagem 20\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Uma caixa est\u00e1 sendo puxada por um trabalhador, conforme mostra a figura. \u00a0Para diminuir a for\u00e7a <\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_b6ef7446.jpg\" alt=\"\" width=\"497\" height=\"170\" name=\"Imagem 21\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>de atrito entre a caixa e o ch\u00e3o, aplica-se, no ponto X, uma for\u00e7a f. O segmento orientado que pode representar esta for\u00e7a est\u00e1 indicado na alternativa:<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_6c96918f.jpg\" alt=\"\" width=\"781\" height=\"95\" name=\"Imagem 22\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>09-(UFSCAR-SP)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_60966351.jpg\" alt=\"\" width=\"450\" height=\"121\" name=\"Imagem 23\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Um menino deseja deslocar um bloco de madeira sobre o ch\u00e3o horizontal puxando uma corda amarrada ao bloco.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Sabendo-se que o coeficiente de atrito est\u00e1tico entre a madeira e o ch\u00e3o vale 0,4, que a massa do bloco \u00e9 42 kg e que a acelera\u00e7\u00e3o da gravidade \u00e9 igual a 10 m\/s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>, e considerando \u221a3 = 1,7, qual a <\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_146ef1ea.jpg\" alt=\"\" width=\"450\" height=\"152\" name=\"Imagem 24\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>menor intensidade da for\u00e7a que o menino deve puxar a corda para deslocar o bloco, se a dire\u00e7\u00e3o da corda forma com o ch\u00e3o um \u00e2ngulo de 60\u00b0?<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_1b6fbc4c.png\" alt=\"\" width=\"775\" height=\"21\" name=\"Imagem 39\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>10-(UFF-RJ)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_d114e25f.jpg\" alt=\"\" width=\"780\" height=\"128\" name=\"Imagem 25\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Um pano de prato retangular, com 60cm de comprimento e constitui\u00e7\u00e3o homog\u00eanea, est\u00e1 em repouso sobre uma mesa, parte sobre sua superf\u00edcie, horizontal e fina, e parte pendente, como mostra a figura.<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_7b809c1c.jpg\" alt=\"\" width=\"463\" height=\"185\" name=\"Imagem 26\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Sabendo-se que o coeficiente de atrito est\u00e1tico entre a superf\u00edcie da mesa\u00a0 e o pano \u00e9 igual a 0,5 e que o pano est\u00e1 na imin\u00eancia de deslizar, pode-se afirmar que o comprimento L da parte sobre a mesa \u00e9:<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_d6da08e4.png\" alt=\"\" width=\"775\" height=\"17\" name=\"Imagem 40\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>11-(UERJ-RJ)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_d556cb8.jpg\" alt=\"\" width=\"768\" height=\"125\" name=\"Imagem 27\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Considere um carro de tra\u00e7\u00e3o dianteira que acelera no sentido indicado na figura em destaque. O motor \u00e9 capaz de impor \u00e0s rodas<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_307f555c.jpg\" alt=\"\" width=\"359\" height=\"150\" name=\"Imagem 28\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>de tra\u00e7\u00e3o um determinado sentido de rota\u00e7\u00e3o. S\u00f3 h\u00e1 movimento quando h\u00e1 atrito est\u00e1tico, pois, na sua aus\u00eancia, as rodas de tra\u00e7\u00e3o patinam sobre o solo, como acontece em um terreno enlameado. O diagrama que representa corretamente as for\u00e7as de atrito est\u00e1tico que o solo exerce sobre as rodas \u00e9:<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_90a5b323.jpg\" alt=\"\" width=\"780\" height=\"124\" name=\"Imagem 29\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>12-(UFG-GO)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_e6594963.jpg\" alt=\"\" width=\"766\" height=\"131\" name=\"Imagem 30\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>A for\u00e7a muscular origina-se nas fibras musculares, conforme figura (a), como resultado das intera\u00e7\u00f5es entre certas prote\u00ednas que experimentam mudan\u00e7as de configura\u00e7\u00e3o e proporcionam a contra\u00e7\u00e3o r\u00e1pida e volunt\u00e1ria do m\u00fasculo.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>A for\u00e7a m\u00e1xima que um m\u00fasculo pode exercer depende da sua \u00e1rea da se\u00e7\u00e3o reta e vale cerca de 30 N\/cm<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>. Considere um oper\u00e1rio que movimenta com uma velocidade constante uma caixa de 120 kg sobre uma superf\u00edcie rugosa, de coeficiente de atrito 0,8, usando os dois bra\u00e7os, conforme ilustrado na figura (b).<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_441bf3d9.jpg\" alt=\"\" width=\"777\" height=\"186\" name=\"Imagem 31\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Dessa forma, a menor se\u00e7\u00e3o reta dos m\u00fasculos de um dos bra\u00e7os do oper\u00e1rio, em cm<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>, e uma das prote\u00ednas respons\u00e1veis pela contra\u00e7\u00e3o das miofibrilas s\u00e3o:<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Dados: g =10,0 m\/s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>a) 16 e actina. \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<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>b) 16 e mielina. \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<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>c) 20 e miosina. \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<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>d) 32 e actina. \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<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>e) 32 e miosina. \u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>13-(UNICAMP-SP)<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_e68613f.jpg\" alt=\"\" width=\"785\" height=\"135\" name=\"Imagem 32\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Acidentes de tr\u00e2nsito causam milhares de mortes todos os anos nas estradas do pa\u00eds. <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Pneus desgastados (\u201ccarecas\u201d), freios em p\u00e9ssimas condi\u00e7\u00f5es e excesso de velocidade s\u00e3o fatores que contribuem para elevar o n\u00famero de acidentes de tr\u00e2nsito.<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>O sistema de freios ABS (do alem\u00e3o \u201cAntiblockier-Bremssystem\u201d) impede o travamento das rodas do ve\u00edculo, de forma que elas<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_5814c43a.jpg\" alt=\"\" width=\"777\" height=\"177\" name=\"Imagem 33\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>n\u00e3o deslizem no ch\u00e3o, o que leva a um menor desgaste do pneu. <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>N\u00e3o havendo deslizamento, a dist\u00e2ncia percorrida pelo ve\u00edculo at\u00e9 a parada completa \u00e9 reduzida, pois a for\u00e7a de atrito aplicada pelo ch\u00e3o nas rodas \u00e9 est\u00e1tica, e seu valor m\u00e1ximo \u00e9 sempre maior que a for\u00e7a de atrito cin\u00e9tico. O coeficiente de atrito est\u00e1tico entre os pneus e a pista \u00e9 \u03bc<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sub><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>e<\/b><\/span><\/span><\/sub><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>= 0,80 e o cin\u00e9tico vale \u03bc<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sub><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>c<\/b><\/span><\/span><\/sub><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\u00a0= 0,60. <\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Sendo g = 10 m\/s<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>2<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>\u00a0e a massa do carro m = 1200 kg, o m\u00f3dulo da for\u00e7a de atrito est\u00e1tico m\u00e1xima e a da for\u00e7a de atrito cin\u00e9tico s\u00e3o, respectivamente, iguais a<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>a) 1200 N e 12000 N. \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<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>b) 12000 N e 120 N. \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<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>c) 20000 N e 15000 N. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>d) 9600 N e 7200 N. \u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial\\ Black, serif;\"><span style=\"font-size: large;\"><b>14-(UFABC-SP)\u00a0<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_9d7902ca.jpg\" alt=\"\" width=\"726\" height=\"120\" name=\"Imagem 34\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Quem diria que uma brincadeira de crian\u00e7a j\u00e1 valeu medalha de ouro. Esse esporte esteve presente em todas as Olimp\u00edadas disputadas entre 1900 e 1920, quando ainda era considerado uma modalidade de atletismo. Em 1908, em Londres, o resultado foi um p\u00f3dio caseiro e fardado. A pol\u00edcia de Londres ficou em primeiro, seguida por policiais de Liverpool e da pol\u00edcia metropolitana, respectivamente. (Revista Galileu, Ed. N<\/b><\/span><\/span><\/span><span style=\"color: #0000cc;\"><sup><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>o<\/b><\/span><\/span><\/sup><\/span><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>204, julho(2008)<\/b><\/span><\/span><\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>Considere duas equipes A e B, formadas por tr\u00eas garotas cada uma, numa disputa de cabo-de-guerra sobre uma superf\u00edcie plana e horizontal, como mostra a figura.<\/b><\/span><\/span><\/span><\/p>\n<p align=\"CENTER\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_763f2c39.jpg\" alt=\"\" width=\"583\" height=\"166\" name=\"Imagem 35\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p><span style=\"color: #0000cc;\">\u00a0<\/span><\/p>\n<p><span style=\"color: #0000cc;\"><span style=\"font-family: Arial, serif;\"><span style=\"font-size: medium;\"><b>A alternativa que mostra corretamente a for\u00e7a de tra\u00e7\u00e3o aplicada pela corda nas m\u00e3os e a for\u00e7a de atrito aplicada pelo solo nos p\u00e9s, respectivamente, de uma integrante da equipe B, durante a disputa, \u00e9<\/b><\/span><\/span><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"http:\/\/fisicaevestibular.com.br\/novo\/wp-content\/uploads\/migracao\/enem\/8\/ENEM8_html_f78c46ad.jpg\" alt=\"leis de Newton\" width=\"781\" height=\"122\" name=\"Imagem 36\" align=\"BOTTOM\" border=\"0\" \/><\/p>\n<p>&nbsp;<\/p>\n<h3><a title=\"Resolu\u00e7\u00e3o Comentada \u2013 Aplica\u00e7\u00f5es das leis de Newton com atrito\" href=\"http:\/\/fisicaevestibular.com.br\/novo\/enem\/aplicacoes-das-leis-de-newton-com-atrito\/resolucao-comentada-aplicacoes-das-leis-de-newton-com-atrito\/\"><span style=\"color: #000080;\">Confira a resolu\u00e7\u00e3o comentada<\/span><\/a><\/h3>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/fisicaevestibular.com.br\/novo\/enem\/\">Clique aqui para ver sobre o tema!<\/a><\/p>\n<p><a href=\"https:\/\/www.youtube.com\/user\/fisicaevestibular\/playlists\">Confira as v\u00eddeo aulas!<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Aplica\u00e7\u00f5es das leis de Newton com atrito Exerc\u00edcios com caracter\u00edsticas de ENEM \u00a0 01-(FUVEST-SP)\u00a0 O gr\u00e1fico a seguir descreve o deslocamento vertical y, para baixo, de um surfista a\u00e9reo de massa igual a 75 kg, em fun\u00e7\u00e3o do tempo t. \u00a0A origem y = 0, em t = 0, \u00e9 tomada na altura do salto. Nesse movimento, a for\u00e7a R<\/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-3627","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3627","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=3627"}],"version-history":[{"count":4,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3627\/revisions"}],"predecessor-version":[{"id":9779,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3627\/revisions\/9779"}],"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=3627"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}