{"id":4881,"date":"2020-01-10T03:12:53","date_gmt":"2020-01-10T03:12:53","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=4881"},"modified":"2024-06-29T23:32:57","modified_gmt":"2024-06-29T23:32:57","slug":"dinamica-impulsiva-2018-2019","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/vestibulares-recentes\/mecanica\/dinamica-impulsiva-2018-2019\/","title":{"rendered":"Din\u00e2mica Impulsiva 2018\/2019"},"content":{"rendered":"

Din\u00e2mica Impulsiva<\/b><\/span><\/span><\/span><\/p>\n

01-(ENEM-MEC-018)<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Um\u00a0<\/b><\/span><\/span>projetista<\/b><\/span><\/span>\u00a0deseja construir um\u00a0<\/b><\/span><\/span>brinquedo que lance um pequeno cubo ao longo de um trilho horizontal,<\/b><\/span><\/span>\u00a0e o dispositivo precisa\u00a0<\/b><\/span><\/span>oferecer a op\u00e7\u00e3o de mudar a velocidade de lan\u00e7amento.\u00a0<\/b><\/span><\/span>Para isso, ele\u00a0<\/b><\/span><\/span>utiliza uma mola e um trilho onde o atrito pode ser desprezado\u00a0<\/b><\/span><\/span>conforme a figura<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Para que a\u00a0<\/b><\/span><\/span>velocidade de lan\u00e7amento do cubo seja aumentada quatro vezes,<\/b><\/span><\/span>\u00a0o projetista deve<\/b><\/span><\/span><\/span><\/span><\/p>\n

(A)\u00a0<\/b><\/span><\/span>manter a mesma mola e aumentar duas vezes a sua deforma\u00e7\u00e3o.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(B)\u00a0<\/b><\/span><\/span>manter a mesma mola e aumentar quatro vezes a sua deforma\u00e7\u00e3o.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(C)\u00a0<\/b><\/span><\/span>manter a mesma mola e aumentar dezesseis vezes a sua deforma\u00e7\u00e3o.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(D)\u00a0<\/b><\/span><\/span>trocar a mola por outra de constante el\u00e1stica duas vezes maior e manter a deforma\u00e7\u00e3o.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(E)\u00a0<\/b><\/span><\/span>trocar a mola por outra de constante el\u00e1stica quatro vezes maior e manter a deforma\u00e7\u00e3o.<\/b><\/span><\/span><\/span><\/span><\/p>\n

02-(Faculdade de Ci\u00eancias M\u00e9dicas da Santa Casa de S\u00e3o Paulo \u2013 SP \u2013 019)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Em um\u00a0<\/b><\/span><\/span><\/span>supermercado,<\/b><\/span><\/span><\/span>\u00a0uma\u00a0<\/b><\/span><\/span><\/span>pessoa empurra seu carrinho de compras com velocidade de 1 m\/s\u00a0<\/b><\/span><\/span><\/span>por um corredor retil\u00edneo.<\/b><\/span><\/span><\/span><\/p>\n

Para\u00a0<\/b><\/span><\/span><\/span>mover o carrinho mais r\u00e1pido,<\/b><\/span><\/span><\/span>\u00a0a\u00a0<\/b><\/span><\/span><\/span>pessoa d\u00e1 sobre ele dois impulsos consecutivos de 0,5 s<\/b><\/span><\/span><\/span>\u00a0de\u00a0<\/b><\/span><\/span><\/span>dura\u00e7\u00e3o cada um, exercendo uma for\u00e7a horizontal na mesma dire\u00e7\u00e3o e no mesmo sentido do movimento do carrinho,\u00a0<\/b><\/span><\/span><\/span>cuja\u00a0<\/b><\/span><\/span><\/span>intensidade varia, em fun\u00e7\u00e3o do tempo, de acordo com o gr\u00e1fico.<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Sabendo que a\u00a0<\/b><\/span><\/span><\/span>massa total do carrinho \u00e9 50 kg\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>desprezando\u00a0<\/b><\/span><\/span><\/span>a a\u00e7\u00e3o das\u00a0<\/b><\/span><\/span><\/span>for\u00e7as dissipativas\u00a0<\/b><\/span><\/span><\/span>sobre ele, a\u00a0<\/b><\/span><\/span><\/span>velocidade do carrinho ao final do segundo impulso\u00a0<\/b><\/span><\/span><\/span>\u00e9<\/b><\/span><\/span><\/span><\/p>\n

(A)\u00a0<\/b><\/span><\/span><\/span>1,4 m\/s.\u00a0<\/b><\/span><\/span><\/span>(B)\u00a0<\/b><\/span><\/span><\/span>1,1 m\/s.\u00a0<\/b><\/span><\/span><\/span>(C)\u00a0<\/b><\/span><\/span><\/span>1,5 m\/s.\u00a0<\/b><\/span><\/span><\/span>(D)\u00a0<\/b><\/span><\/span><\/span>1,2 m\/s.\u00a0<\/b><\/span><\/span><\/span>(E)\u00a0<\/b><\/span><\/span><\/span>1,3 m\/s.<\/b><\/span><\/span><\/span><\/p>\n

03- (FAMERP 2019 \u2013 Conhecimentos Gerais)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Analise o gr\u00e1fico que mostra a\u00a0<\/b><\/span><\/span><\/span>varia\u00e7\u00e3o da velocidade escalar, em fun\u00e7\u00e3o do tempo, de um autom\u00f3vel de massa 1200 kg que se desloca em uma pista retil\u00ednea horizontal<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

A\u00a0<\/b><\/span><\/span><\/span>intensidade m\u00e9dia da for\u00e7a<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>resultante sobre esse autom\u00f3vel<\/b><\/span><\/span><\/span>,\u00a0<\/b><\/span><\/span><\/span>no intervalo de tempo entre zero e quatro segundos<\/b><\/span><\/span><\/span>, \u00e9<\/b><\/span><\/span><\/span><\/p>\n

(A) 2400 N.<\/b><\/span><\/span><\/span><\/p>\n

(B) 4800 N.<\/b><\/span><\/span><\/span><\/p>\n

(C) 3000 N.<\/b><\/span><\/span><\/span><\/p>\n

(D) 3600 N.<\/b><\/span><\/span><\/span><\/p>\n

(E) 480 N.<\/b><\/span><\/span><\/span><\/p>\n

 <\/p>\n

04-(PUC-SP-019)<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

Considere\u00a0<\/b><\/span><\/span>uma part\u00edcula de massa m, suspensa por um fio que descreve um movimento circular de raio r, sobre<\/b><\/span><\/span>\u00a0uma\u00a0<\/b><\/span><\/span>superf\u00edcie horizontal perfeitamente lisa e com velocidade angular constante, em torno de um eixo vertical imagin\u00e1rio,\u00a0<\/b><\/span><\/span>conforme representado na\u00a0<\/b><\/span><\/span>figura abaixo.<\/b><\/span><\/span><\/span><\/span><\/p>\n

<\/p>\n

O\u00a0<\/b><\/span><\/span>m\u00f3dulo da tra\u00e7\u00e3o no fio que sustenta a part\u00edcula est\u00e1 representado por T.\u00a0<\/b><\/span><\/span>Com\u00a0<\/b><\/span><\/span>rela\u00e7\u00e3o \u00e0 situa\u00e7\u00e3o descrita, \u00e9 CORRETO afirmar<\/b><\/span><\/span>\u00a0que:<\/b><\/span><\/span><\/span><\/span><\/p>\n

A)\u00a0<\/b><\/span><\/span>O momento gerado pela for\u00e7a resultante \u00e9 nulo em rela\u00e7\u00e3o ao centro da trajet\u00f3ria.<\/b><\/span><\/span><\/span><\/span><\/p>\n

B)\u00a0<\/b><\/span><\/span>O vetor quantidade de movimento \u00e9 constante, pois a velocidade angular \u00e9 constante.<\/b><\/span><\/span><\/span><\/span><\/p>\n

C)\u00a0<\/b><\/span><\/span>O momento gerado pela for\u00e7a resultante, em rela\u00e7\u00e3o ao centro da trajet\u00f3ria, \u00e9 dado por r.Tcos\u03b8.\u00a0<\/b><\/span><\/span><\/span><\/span><\/p>\n

D)\u00a0<\/b><\/span><\/span>O momento gerado pela for\u00e7a resultante, em rela\u00e7\u00e3o ao centro da trajet\u00f3ria, \u00e9 dado por r.Tsen\u03b8.<\/b><\/span><\/span><\/span><\/span><\/p>\n

 <\/p>\n

05-(FUVEST-SP-018)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Uma\u00a0<\/b><\/span><\/span><\/span>caminhonete,\u00a0<\/b><\/span><\/span><\/span>de\u00a0<\/b><\/span><\/span><\/span>massa 2.000 kg, bateu na traseira de um sed\u00e3,\u00a0<\/b><\/span><\/span><\/span>de\u00a0<\/b><\/span><\/span><\/span>massa 1.000 kg,\u00a0<\/b><\/span><\/span><\/span>que estava<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

parado no sem\u00e1foro,\u00a0<\/b><\/span><\/span><\/span>em uma\u00a0<\/b><\/span><\/span><\/span>rua horizontal.<\/b><\/span><\/span><\/span><\/p>\n

Ap\u00f3s o impacto,\u00a0<\/b><\/span><\/span><\/span>os\u00a0<\/b><\/span><\/span><\/span>dois ve\u00edculos\u00a0<\/b><\/span><\/span><\/span>deslizaram como um\u00a0<\/b><\/span><\/span><\/span>\u00fanico bloco.<\/b><\/span><\/span><\/span><\/p>\n

Para a\u00a0<\/b><\/span><\/span><\/span>per\u00edcia,<\/b><\/span><\/span><\/span>\u00a0o\u00a0<\/b><\/span><\/span><\/span>motorista da caminhonete\u00a0<\/b><\/span><\/span><\/span>alegou que estava a\u00a0<\/b><\/span><\/span><\/span>menos de 20 km\/h\u00a0<\/b><\/span><\/span><\/span>quando o\u00a0<\/b><\/span><\/span><\/span>acidente ocorreu.\u00a0<\/b><\/span><\/span><\/span>A\u00a0<\/b><\/span><\/span><\/span>per\u00edcia constatou,\u00a0<\/b><\/span><\/span><\/span>analisando as\u00a0<\/b><\/span><\/span><\/span>marcas de frenagem,\u00a0<\/b><\/span><\/span><\/span>que a\u00a0<\/b><\/span><\/span><\/span>caminhonete arrastou o sed\u00e3, em linha reta, por uma dist\u00e2ncia de 10 m.<\/b><\/span><\/span><\/span><\/p>\n

Com\u00a0<\/b><\/span><\/span><\/span>este dado\u00a0<\/b><\/span><\/span><\/span>e estimando que o\u00a0<\/b><\/span><\/span><\/span>coeficiente de atrito cin\u00e9tico entre os pneus dos ve\u00edculos\u00a0<\/b><\/span><\/span><\/span>e o\u00a0<\/b><\/span><\/span><\/span>asfalto, no local do acidente, era 0,5,\u00a0<\/b><\/span><\/span><\/span>a per\u00edcia concluiu que a\u00a0<\/b><\/span><\/span><\/span>velocidade real da caminhonete,<\/b><\/span><\/span><\/span>\u00a0em\u00a0<\/b><\/span><\/span><\/span>km\/h, no momento da colis\u00e3o\u00a0<\/b><\/span><\/span><\/span>era, aproximadamente,<\/b><\/span><\/span><\/span><\/p>\n

06-(UNESP-SP-018)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

A\u00a0<\/b><\/span><\/span><\/span>figura mostra a trajet\u00f3ria\u00a0<\/b><\/span><\/span><\/span>de um\u00a0<\/b><\/span><\/span><\/span>proj\u00e9til lan\u00e7ado obliquamente\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>cinco pontos equidistantes entre si\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>localizados sobre o solo horizontal.<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

07- (Faculdade de Ci\u00eancias M\u00e9dicas da Santa Casa de S\u00e3o Paulo \u2013 018)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

<\/p>\n

08- (Faculdade de Medicina de Jundia\u00ed \u201cFMJ\u201d \u2013SP \u2013 018)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

A\u00a0<\/b><\/span><\/span><\/span>figura mostra o perfil\u00a0<\/b><\/span><\/span><\/span>de uma\u00a0<\/b><\/span><\/span><\/span>pista em que h\u00e1 um patamar de altura h\u00a0<\/b><\/span><\/span><\/span>em\u00a0<\/b><\/span><\/span><\/span>rela\u00e7\u00e3o ao n\u00edvel mais baixo.<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Um\u00a0<\/b><\/span><\/span><\/span>bloco A, de massa m,\u00a0<\/b><\/span><\/span><\/span>\u00e9\u00a0<\/b><\/span><\/span><\/span>abandonado de uma altura H > h\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>colide frontalmente,\u00a0<\/b><\/span><\/span><\/span>de forma\u00a0<\/b><\/span><\/span><\/span>perfeitamente el\u00e1stica, com o bloco B, tamb\u00e9m de massa m,\u00a0<\/b><\/span><\/span><\/span>em\u00a0<\/b><\/span><\/span><\/span>repouso no n\u00edvel mais baixo\u00a0<\/b><\/span><\/span><\/span>da\u00a0<\/b><\/span><\/span><\/span>pista. Desprezando o atrito\u00a0<\/b><\/span><\/span><\/span>e a\u00a0<\/b><\/span><\/span><\/span>resist\u00eancia do ar\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>sabendo<\/b><\/span><\/span><\/span>\u00a0que os\u00a0<\/b><\/span><\/span><\/span>corpos n\u00e3o perdem contato\u00a0<\/b><\/span><\/span><\/span>com a\u00a0<\/b><\/span><\/span><\/span>pista<\/b><\/span><\/span><\/span>\u00a0em\u00a0<\/b><\/span><\/span><\/span>momento algum, \u00e9 correto afirmar\u00a0<\/b><\/span><\/span><\/span>que,\u00a0<\/b><\/span><\/span><\/span>ap\u00f3s a colis\u00e3o,\u00a0<\/b><\/span><\/span><\/span>o\u00a0<\/b><\/span><\/span><\/span>bloco A<\/b><\/span><\/span><\/span><\/p>\n

(A)\u00a0<\/b><\/span><\/span><\/span>retorna at\u00e9 a altura h e o bloco B n\u00e3o atinge o patamar.<\/b><\/span><\/span><\/span><\/p>\n

(B)\u00a0<\/b><\/span><\/span><\/span>retorna para a altura H e o bloco B n\u00e3o atinge o patamar.<\/b><\/span><\/span><\/span><\/p>\n

(C)\u00a0<\/b><\/span><\/span><\/span>retorna para a altura H e o bloco B ultrapassa o patamar, atingindo o ponto P.<\/b><\/span><\/span><\/span><\/p>\n

(D)\u00a0<\/b><\/span><\/span><\/span>para no local da colis\u00e3o e o bloco B ultrapassa o patamar, atingindo o ponto P.<\/b><\/span><\/span><\/span><\/p>\n

(E)\u00a0<\/b><\/span><\/span><\/span>para no local da colis\u00e3o e o bloco B para sobre o patamar<\/b><\/span><\/span><\/span><\/p>\n

09-(PUC-RJ\/018)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

\"Din\u00e2mica<\/p>\n

Confira a resolu\u00e7\u00e3o comentada<\/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":"

Din\u00e2mica Impulsiva 01-(ENEM-MEC-018) Um\u00a0projetista\u00a0deseja construir um\u00a0brinquedo que lance um pequeno cubo ao longo de um trilho horizontal,\u00a0e o dispositivo precisa\u00a0oferecer a op\u00e7\u00e3o de mudar a velocidade de lan\u00e7amento.\u00a0Para isso, ele\u00a0utiliza uma mola e um trilho onde o atrito pode ser desprezado\u00a0conforme a figura. Para que a\u00a0velocidade de lan\u00e7amento do cubo seja aumentada quatro vezes,\u00a0o projetista deve (A)\u00a0manter a mesma mola<\/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-4881","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4881","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=4881"}],"version-history":[{"count":4,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4881\/revisions"}],"predecessor-version":[{"id":9880,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4881\/revisions\/9880"}],"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=4881"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}