{"id":4843,"date":"2020-01-09T14:06:26","date_gmt":"2020-01-09T14:06:26","guid":{"rendered":"http:\/\/fisicaevestibular.com.br\/novo\/?page_id=4843"},"modified":"2024-06-30T00:11:39","modified_gmt":"2024-06-30T00:11:39","slug":"eletrostatica-2018-2019","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/vestibulares-recentes\/eletricidade\/eletrostatica-2018-2019\/","title":{"rendered":"ELETROST\u00c1TICA \u2013 2018\/2019"},"content":{"rendered":"

Vestibulares Recentes <\/span><\/span><\/span><\/h4>\n

ELETRICIDADE \u2013 2018\/2019<\/span><\/span><\/span><\/h4>\n

ELETROST\u00c1TICA \u2013 2018\/2019<\/b><\/span><\/span><\/span><\/p>\n

Carga el\u00e9trica e processos de eletriza\u00e7\u00e3o<\/b><\/u><\/span><\/span><\/span><\/a><\/p>\n

01-Col\u00e9gio Naval 2018\/2019<\/b><\/span><\/span><\/span><\/span><\/span><\/p>\n

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Sobre\u00a0<\/b><\/span><\/span>eletricidade<\/b><\/span><\/span>\u00a0e\u00a0<\/b><\/span><\/span>magnetismo<\/b><\/span><\/span>\u00a0analise as afirmativas abaixo e assinale a op\u00e7\u00e3o que apresenta o\u00a0<\/b><\/span><\/span>conceito INCORRETO<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(A) Part\u00edculas ou corpos com\u00a0<\/b><\/span><\/span>cargas el\u00e9tricas<\/b><\/span><\/span>\u00a0de\u00a0<\/b><\/span><\/span>sinais iguais<\/b><\/span><\/span>\u00a0se\u00a0<\/b><\/span><\/span>repelem<\/b><\/span><\/span>\u00a0e com\u00a0<\/b><\/span><\/span>sinais diferentes<\/b><\/span><\/span>\u00a0se\u00a0<\/b><\/span><\/span>atraem<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(B) Um corpo \u00e9 dito\u00a0<\/b><\/span><\/span>neutro<\/b><\/span><\/span>\u00a0quando possui\u00a0<\/b><\/span><\/span>igual quantidade de pr\u00f3tons e el\u00e9trons<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(C) Um corpo \u00e9 dito\u00a0<\/b><\/span><\/span>eletrizado positivamente<\/b><\/span><\/span>\u00a0quando inicialmente\u00a0<\/b><\/span><\/span>neutro<\/b><\/span><\/span>, por algum processo de eletriza\u00e7\u00e3o\u00a0<\/b><\/span><\/span>recebe pr\u00f3tons<\/b><\/span><\/span>\u00a0de outro corpo.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(D) Em um sistema eletricamente isolado,\u00a0<\/b><\/span><\/span>dois corpos<\/b><\/span><\/span>\u00a0inicialmente\u00a0<\/b><\/span><\/span>neutros<\/b><\/span><\/span>\u00a0e de\u00a0<\/b><\/span><\/span>materiais diferentes<\/b><\/span><\/span>, quando atritados entre si adquirem cargas el\u00e9tricas de\u00a0<\/b><\/span><\/span>mesmo m\u00f3dulo<\/b><\/span><\/span>\u00a0e de\u00a0<\/b><\/span><\/span>sinais opostos<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/p>\n

(E) A Terra pode ser considerada como se fosse um grande \u00edm\u00e3, em que o\u00a0<\/b><\/span><\/span>polo magn\u00e9tico norte<\/b><\/span><\/span>\u00a0encontra-se pr\u00f3ximo ao\u00a0<\/b><\/span><\/span>polo geogr\u00e1fico sul<\/b><\/span><\/span>\u00a0e o\u00a0<\/b><\/span><\/span>polo magn\u00e9tico sul<\/b><\/span><\/span>\u00a0pr\u00f3ximo ao\u00a0<\/b><\/span><\/span>polo geogr\u00e1fico norte<\/b><\/span><\/span>.<\/b><\/span><\/span><\/span><\/span><\/p>\n

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

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Considere\u00a0<\/b><\/span><\/span><\/span>cinco esferas met\u00e1licas condutoras, id\u00eanticas\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>bem distantes entre si, apoiadas em suportes isolantes.<\/b><\/span><\/span><\/span><\/p>\n

A\u00a0<\/b><\/span><\/span><\/span>esfera 1 \u00e9 eletrizada com carga Q,\u00a0<\/b><\/span><\/span><\/span>estando as\u00a0<\/b><\/span><\/span><\/span>demais eletricamente neutras.<\/b><\/span><\/span><\/span><\/p>\n

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A\u00a0<\/b><\/span><\/span><\/span>esfera 1 \u00e9 colocada em contatos sucessivos com as esferas 2, 3, 4 e 5, respectivamente.<\/b><\/span><\/span><\/span><\/p>\n

Ap\u00f3s os contatos citados, as esferas 1, 3 e 5 s\u00e3o postas em contato simult\u00e2neo e depois separadas novamente.<\/b><\/span><\/span><\/span><\/p>\n

Podemos\u00a0<\/b><\/span><\/span><\/span>afirmar que a carga final da ESFERA 3, ap\u00f3s todos os contatos citados, ser\u00e1 igual\u00a0<\/b><\/span><\/span><\/span>a:<\/b><\/span><\/span><\/span><\/p>\n

A)\u00a0<\/b><\/span><\/span><\/span>Q\/8\u00a0<\/b><\/span><\/span><\/span>B)\u00a0<\/b><\/span><\/span><\/span>3Q\/8\u00a0<\/b><\/span><\/span><\/span>C)\u00a0<\/b><\/span><\/span><\/span>13Q\/16\u00a0<\/b><\/span><\/span><\/span>D)\u00a0<\/b><\/span><\/span><\/span>13Q\/48<\/b><\/span><\/span><\/span><\/p>\n

03-(ESCOLA T\u00c9CNICA ESTADUAL \u2013 ETEC \u2013 SP \u2013 019)<\/b><\/span><\/span><\/span><\/p>\n

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Um\u00a0<\/b><\/span><\/span><\/span>corpo neutro foi eletrizado com 1 Coulomb. Para que isso fosse poss\u00edvel,\u00a0<\/b><\/span><\/span><\/span>a\u00a0<\/b><\/span><\/span><\/span>quantidade de el\u00e9trons que foram retirados do corpo foi:\u00a0<\/b><\/span><\/span><\/span>Dado:<\/b><\/span><\/span><\/span>\u00a0e = \u2013 1,6.10-19\u00a0C.<\/b><\/span><\/span><\/span><\/p>\n

(A)\u00a0<\/b><\/span><\/span><\/span>1,6.1018<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>(B)\u00a0<\/b><\/span><\/span><\/span>1,6.10\u201319<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>(C)\u00a0<\/b><\/span><\/span><\/span>6,25.1018<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>(D)\u00a0<\/b><\/span><\/span><\/span>6,25.10\u201319\u00a0(E) 1.10\u201319<\/b><\/span><\/span><\/span><\/p>\n

04-(ESCOLA T\u00c9CNICA ESTADUAL \u2013 ETEC \u2013 SP \u2013 019)<\/b><\/span><\/span><\/span><\/p>\n

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Em uma\u00a0<\/b><\/span><\/span><\/span>aula de laborat\u00f3rio de eletricidade,\u00a0<\/b><\/span><\/span><\/span>um aluno\u00a0<\/b><\/span><\/span><\/span>realizou a seguinte experi\u00eancia:<\/b><\/span><\/span><\/span><\/p>\n

\u2013\u00a0<\/span>Separou 5 esferas id\u00eanticas e eletricamente neutras;<\/b><\/span><\/span><\/span><\/p>\n

\u2013\u00a0<\/span>Eletrizou uma delas com uma carga de valor Q;<\/b><\/span><\/span><\/span><\/p>\n

\u2013\u00a0<\/span>Separadamente, colocou a esfera eletrizada em contato com cada uma das outras esferas.<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Assim,\u00a0<\/b><\/span><\/span><\/span>a esfera que foi, inicialmente, carregada com carga Q, ter\u00e1 sua carga final de valor:<\/b><\/span><\/span><\/span><\/p>\n

(A)\u00a0<\/b><\/span><\/span><\/span>1Q\/7\u00a0<\/b><\/span><\/span><\/span>(B)\u00a0<\/b><\/span><\/span><\/span>1Q\/16\u00a0<\/b><\/span><\/span><\/span>(C)\u00a0<\/b><\/span><\/span><\/span>2Q\/16\u00a0<\/b><\/span><\/span><\/span>(D)\u00a0<\/b><\/span><\/span><\/span>1Q\/32\u00a0<\/b><\/span><\/span><\/span>(E)\u00a0<\/b><\/span><\/span><\/span>1Q\/64<\/b><\/span><\/span><\/span><\/p>\n

05-(UFAM-AM-2019)<\/b><\/span><\/span><\/span><\/p>\n

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S\u00e3o\u00a0<\/b><\/span><\/span><\/span>tr\u00eas os processos de eletriza\u00e7\u00e3o<\/b><\/span><\/span><\/span>:\u00a0<\/b><\/span><\/span><\/span>por\u00a0<\/b><\/span><\/span><\/span>atrito<\/b><\/span><\/span><\/span>,<\/b><\/span><\/span><\/span>\u00a0por\u00a0<\/b><\/span><\/span><\/span>contato<\/b><\/span><\/span><\/span>\u00a0e por\u00a0<\/b><\/span><\/span><\/span>indu\u00e7\u00e3o.<\/b><\/span><\/span><\/span>\u00a0Considere as\u00a0<\/b><\/span><\/span><\/span>seguintes afirmativas:<\/b><\/span><\/span><\/span><\/p>\n

I.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Na\u00a0<\/b><\/span><\/span><\/span>eletriza\u00e7\u00e3o por atrito, al\u00e9m de adquirirem cargas el\u00e9tricas de sinais opostos,\u00a0<\/b><\/span><\/span><\/span>os corpos apresentam\u00a0<\/b><\/span><\/span><\/span>quantidades de cargas el\u00e9tricas de mesmo valor absoluto.<\/b><\/span><\/span><\/span><\/p>\n

II.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Na\u00a0<\/b><\/span><\/span><\/span>eletriza\u00e7\u00e3o por atrito,\u00a0<\/b><\/span><\/span><\/span>as subst\u00e2ncias podem\u00a0<\/b><\/span><\/span><\/span>ser distribu\u00eddas numa sequ\u00eancia, denominada s\u00e9rie triboel\u00e9trica,<\/b><\/span><\/span><\/span>\u00a0de\u00a0<\/b><\/span><\/span><\/span>acordo com o sinal da carga que adquirem ao serem atritadas umas com as outras.<\/b><\/span><\/span><\/span><\/p>\n

III.\u00a0Tanto nos processo de eletriza\u00e7\u00e3o por contato, quanto no processo de eletriza\u00e7\u00e3o por indu\u00e7\u00e3o, um dos corpos deve, inicialmente, estar carregado eletricamente.<\/b><\/span><\/span><\/span><\/p>\n

IV.\u00a0Tanto nos processo de eletriza\u00e7\u00e3o por contato, quanto no processo de eletriza\u00e7\u00e3o por indu\u00e7\u00e3o, torna-se necess\u00e1rio que um dos corpos seja ligado temporariamente a um aterramento.<\/b><\/span><\/span><\/span><\/p>\n

V.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Nos\u00a0<\/b><\/span><\/span><\/span>tr\u00eas processos de eletriza\u00e7\u00e3o, torna-se necess\u00e1rio manter, temporariamente, um contato direto entre os corpos.<\/b><\/span><\/span><\/span><\/p>\n

Assinale\u00a0<\/b><\/span><\/span><\/span>a alternativa correta:<\/b><\/span><\/span><\/span><\/p>\n

a)\u00a0<\/b><\/span><\/span><\/span>Somente as afirmativas\u00a0<\/b><\/span><\/span><\/span>I, II e III est\u00e3o corretas.<\/b><\/span><\/span><\/span><\/p>\n

b)\u00a0<\/b><\/span><\/span><\/span>Somente as afirmativas\u00a0<\/b><\/span><\/span><\/span>I, III e V est\u00e3o corretas.<\/b><\/span><\/span><\/span><\/p>\n

c)\u00a0<\/b><\/span><\/span><\/span>Somente as afirmativas\u00a0<\/b><\/span><\/span><\/span>II, III e IV est\u00e3o corretas.<\/b><\/span><\/span><\/span><\/p>\n

d)\u00a0<\/b><\/span><\/span><\/span>Somente as afirmativas\u00a0<\/b><\/span><\/span><\/span>II, III e V est\u00e3o corretas.<\/b><\/span><\/span><\/span><\/p>\n

e)\u00a0<\/b><\/span><\/span><\/span>Somente as afirmativas\u00a0<\/b><\/span><\/span><\/span>III, IV e V est\u00e3o corretas<\/b><\/span><\/span><\/span><\/p>\n

For\u00e7a el\u00e9trica e Campo el\u00e9trico<\/b><\/span><\/span><\/span><\/p>\n

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06-(CEDERJ-RJ-2018)<\/b><\/span><\/span><\/span><\/p>\n

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A\u00a0<\/b><\/span><\/span><\/span>figura mostra duas part\u00edculas A e B<\/b><\/span><\/span><\/span>\u00a0de\u00a0<\/b><\/span><\/span><\/span>massas respectivamente iguais a mA\u00a0e mB<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>cargas el\u00e9- tricas qA\u00a0e qB.<\/b><\/span><\/span><\/span><\/p>\n

Considere<\/b><\/span><\/span><\/span>\u00a0que elas est\u00e3o\u00a0<\/b><\/span><\/span><\/span>sujeitas exclusivamente \u00e0s for\u00e7as eletrost\u00e1ticas m\u00fatuas devidas \u00e0s suas cargas<\/b><\/span><\/span><\/span>\u00a0e que as\u00a0<\/b><\/span><\/span><\/span>setas na figura representam suas respectivas acelera\u00e7\u00f5es vetoriais:<\/b><\/span><\/span><\/span><\/p>\n

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Comparando<\/b><\/span><\/span><\/span>\u00a0as\u00a0<\/b><\/span><\/span><\/span>cargas<\/b><\/span><\/span><\/span>\u00a0e as\u00a0<\/b><\/span><\/span><\/span>massas das part\u00edculas, conclui-se\u00a0<\/b><\/span><\/span><\/span>que<\/b><\/span><\/span><\/span><\/p>\n

(A)\u00a0<\/b><\/span><\/span><\/span>|qA| < |qB| e mB\u00a0= mA<\/b><\/span><\/span><\/span><\/p>\n

(B)\u00a0<\/b><\/span><\/span><\/span>|qA| > |qB| e mB\u00a0= mA<\/b><\/span><\/span><\/span><\/p>\n

(C)\u00a0<\/b><\/span><\/span><\/span>qA\u00a0tem sinal oposto ao de qB\u00a0e mA\u00a0> mB<\/b><\/span><\/span><\/span><\/p>\n

(D)\u00a0<\/b><\/span><\/span><\/span>qA\u00a0tem sinal id\u00eantico ao de qB\u00a0e mA\u00a0> mB<\/b><\/span><\/span><\/span><\/p>\n

07- (FAMERP-SP-018)<\/b><\/span><\/span><\/span><\/p>\n

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08-(UEMG-MG-019)<\/b><\/span><\/span><\/span><\/p>\n

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\u201cFundado em 2002 pelo\u00a0<\/b><\/span><\/span><\/span>Pr\u00eamio Nobel Carl Wieman,<\/b><\/span><\/span><\/span>\u00a0o projeto\u00a0<\/b><\/span><\/span><\/span>PhET Simula\u00e7\u00f5es Interativas\u00a0<\/b><\/span><\/span><\/span>da Universidade de Colorado Boulder (EUA)\u00a0<\/b><\/span><\/span><\/span>cria simula\u00e7\u00f5es interativas gratuitas de matem\u00e1tica e ci\u00eancias.<\/b><\/span><\/span><\/span><\/p>\n

As\u00a0<\/b><\/span><\/span><\/span>simula\u00e7\u00f5es PhET baseiam-se em extensa pesquisa em educa\u00e7\u00e3o\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>envolvem os alunos atrav\u00e9s de um ambiente intuitivo, estilo jogo, onde os alunos aprendem atrav\u00e9s da explora\u00e7\u00e3o e da descoberta\u201d.\u00a0<\/b><\/span><\/span><\/span>A\u00a0<\/b><\/span><\/span><\/span>figura a seguir foi obtida pelo PhET,\u00a0<\/b><\/span><\/span><\/span>sendo que\u00a0<\/b><\/span><\/span><\/span>duas part\u00edculas A e B, eletricamente carregadas, foram colocadas em uma determinada regi\u00e3o do espa\u00e7o.<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>As\u00a0<\/b><\/span><\/span><\/span>setas\u00a0indicam a\u00a0dire\u00e7\u00e3o e o sentido das linhas de for\u00e7a do vetor campo el\u00e9trico do sistema.<\/b><\/span><\/span><\/span><\/p>\n

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09-Universidade Estadual de Maring\u00e1\u00a0(UEM) \u2013 019<\/b><\/span><\/span><\/span><\/p>\n

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

Uma\u00a0<\/b><\/span><\/span><\/span>pequena esfera eletricamente carregada, de massa m = 10g e carga q = 5.10-6\u00a0C cai verticalmente a partir do repouso em uma regi\u00e3o em que atua um campo el\u00e9trico constante e uniforme\u00a0.<\/b><\/span><\/span><\/span><\/p>\n

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Esse\u00a0<\/b><\/span><\/span><\/span>campo tem dire\u00e7\u00e3o vertical, aponta para baixo\u00a0<\/b><\/span><\/span><\/span>e tem\u00a0<\/b><\/span><\/span><\/span>m\u00f3dulo igual a 200 V\/m\u00a0<\/b><\/span><\/span><\/span>(\u00a0\u00e9 paralelo ao campo gravitacional da Terra no local do experimento).\u00a0<\/b><\/span><\/span><\/span>Despreze a resist\u00eancia do ar\u00a0<\/b><\/span><\/span><\/span>e\u00a0<\/b><\/span><\/span><\/span>considere g = 9,8 m\/s2. Assinale<\/b><\/span><\/span><\/span>\u00a0o que\u00a0<\/b><\/span><\/span><\/span>for correto.<\/b><\/span><\/span><\/span><\/p>\n

01)<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Apesar da presen\u00e7a do campo el\u00e9trico, a esfera cai com acelera\u00e7\u00e3o constante e igual a g, visto que seu peso \u00e9 igual a mg.<\/b><\/span><\/span><\/span><\/p>\n

02)<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Em m\u00f3dulo, a velocidade da esfera \u00e9 igual a 4,85m\/s ap\u00f3s meio segundo de queda.<\/b><\/span><\/span><\/span><\/p>\n

04)<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>A esfera percorre 4,85m no primeiro segundo de queda.<\/b><\/span><\/span><\/span><\/p>\n

08)<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>A raz\u00e3o entre o peso da esfera e a for\u00e7a de origem eletrost\u00e1tica que atua sobre ela, em m\u00f3dulo, \u00e9 igual a 98.<\/b><\/span><\/span><\/span><\/p>\n

16)<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span>Se a resist\u00eancia do ar fosse levada em conta, a velocidade terminal da esfera n\u00e3o dependeria de\u00a0.<\/b><\/span><\/span><\/span><\/p>\n

10-(ITA \u2013 SP \u2013 019)<\/b><\/span><\/span><\/span>\u00a0<\/b><\/span><\/span><\/span><\/p>\n

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Na figura mostra-se o valor do\u00a0<\/b><\/span><\/span><\/span>potencial el\u00e9trico para diferentes pontos<\/b><\/span><\/span><\/span>\u00a0P(50 V), Q(60 V), R(130 V) e S(120 V) situados no plano xy. Considere o\u00a0<\/b><\/span><\/span><\/span>campo el\u00e9trico uniforme nessa regi\u00e3o\u00a0<\/b><\/span><\/span><\/span>e o\u00a0<\/b><\/span><\/span><\/span>comprimento dos segmentos\u00a0igual a 5,0 m<\/b><\/span><\/span><\/span>, pode-se afirmar que\u00a0<\/b><\/span><\/span><\/span>a magnitude do campo el\u00e9trico \u00e9\u00a0<\/b><\/span><\/span><\/span>igual a<\/b><\/span><\/span><\/span><\/p>\n

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A () 12,0 V\/m<\/b><\/span><\/span><\/span><\/p>\n

B () 8,0 V\/m<\/b><\/span><\/span><\/span><\/p>\n

C () 6,0 V\/m<\/b><\/span><\/span><\/span><\/p>\n

D () 10,0 V\/m<\/b><\/span><\/span><\/span><\/p>\n

E () 16 V\/m<\/b><\/span><\/span><\/span><\/p>\n

11-Escola Naval 2018\/2019<\/b><\/span><\/span><\/span><\/p>\n

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Analise a figura abaixo.<\/b><\/span><\/span><\/span><\/p>\n

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A figura acima mostra uma\u00a0<\/b><\/span><\/span><\/span>casca esf\u00e9rica de raio interno a e raio externo 4a,\u00a0<\/b><\/span><\/span><\/span>ambos em metros, carregada com\u00a0<\/b><\/span><\/span><\/span>densidade volum\u00e9trica de carga p=2\/a3\u00a0(C\/m3).\u00a0<\/b><\/span><\/span><\/span>No centro geom\u00e9trico da casca,\u00a0<\/b><\/span><\/span><\/span>h\u00e1 uma carga pontual q= -379 C.<\/b><\/span><\/span><\/span>\u00a0Estando o sistema de cargas descrito acima\u00a0<\/b><\/span><\/span><\/span>isolado numa regi\u00e3o de v\u00e1cuo,\u00a0<\/b><\/span><\/span><\/span>qual o m\u00f3dulo, a dire\u00e7\u00e3o e o sentido do vetor campo el\u00e9trico, em newtons\/coulomb, nos pontos do espa\u00e7o que distam 5a metros da carga pontual?<\/b><\/span><\/span><\/span><\/p>\n

Dados: a \u00e9 um n\u00famero inteiro positivo, k0\u00a0\u00e9 a constante el\u00e9trica no v\u00e1cuo, considere \u03c0 = 3<\/b><\/span><\/span><\/span><\/p>\n

(A) 5k0\u00a0\/ a2, radial para dentro.<\/b><\/span><\/span><\/span><\/p>\n

(B) 5k0\u00a0\/ a2, radial para fora.<\/b><\/span><\/span><\/span><\/p>\n

(C) 25k0\u00a0\/ a2, tangencial no sentido anti-hor\u00e1rio.<\/b><\/span><\/span><\/span><\/p>\n

(D) 25k0\u00a0\/ a2, radial para fora.<\/b><\/span><\/span><\/span><\/p>\n

(E) 25k0\u00a0\/ a2, tangencial no sentido hor\u00e1rio.<\/b><\/span><\/span><\/span><\/p>\n

12-<\/b><\/span><\/span><\/span>FAMERP \u2013 Conhecimentos espec\u00edficos<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Duas\u00a0<\/b><\/span><\/span><\/span>esferas met\u00e1licas de dimens\u00f5es diferentes<\/b><\/span><\/span><\/span>, situadas no ar, s\u00e3o eletrizadas e colocadas sobre suportes isolantes com\u00a0<\/b><\/span><\/span><\/span>seus centros distando 6,0 metros<\/b><\/span><\/span><\/span>\u00a0entre si. As esferas\u00a0<\/b><\/span><\/span><\/span>s\u00e3o unidas com um fio condutor at\u00e9 que atinja o equil\u00edbrio eletrost\u00e1tico<\/b><\/span><\/span><\/span>, situa\u00e7\u00e3o em que a\u00a0<\/b><\/span><\/span><\/span>esfera A fica eletrizada com carga positiva de valor 8,0 \u00d7 10-8\u00a0C<\/b><\/span><\/span><\/span>\u00a0e\u00a0<\/b><\/span><\/span><\/span>a esfera B com carga tamb\u00e9m positiva de valor 5,0 \u00d7 10-8\u00a0C<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

a) Considerando que, para atingir o\u00a0<\/b><\/span><\/span><\/span>equil\u00edbrio<\/b><\/span><\/span><\/span>,\u00a0<\/b><\/span><\/span><\/span>2,0 \u00d7 1011\u00a0el\u00e9trons foram transferidos entre as esferas<\/b><\/span><\/span><\/span>, que a\u00a0<\/b><\/span><\/span><\/span>carga de cada el\u00e9tron<\/b><\/span><\/span><\/span>\u00a0\u00e9, em m\u00f3dulo,\u00a0<\/b><\/span><\/span><\/span>1,6 \u00d7 10-19\u00a0C<\/b><\/span><\/span><\/span>\u00a0e que o processo durou\u00a0<\/b><\/span><\/span><\/span>4,0 \u00d7 10-6\u00a0segundos<\/b><\/span><\/span><\/span>, calcule a\u00a0<\/b><\/span><\/span><\/span>intensidade m\u00e9dia da corrente el\u00e9trica<\/b><\/span><\/span><\/span>,\u00a0<\/b><\/span><\/span><\/span>em amp\u00e8res<\/b><\/span><\/span><\/span>, que percorreu o condutor nesse intervalo de tempo.<\/b><\/span><\/span><\/span><\/p>\n

b) Considerando a\u00a0<\/b><\/span><\/span><\/span>constante eletrost\u00e1tica do ar igual a 9,0 \u00d7 109\u00a0(N \u00b7 m2)\/C2<\/b><\/span><\/span><\/span>, calcule a\u00a0<\/b><\/span><\/span><\/span>intensidade do campo el\u00e9trico<\/b><\/span><\/span><\/span>, em N\/C, resultante da a\u00e7\u00e3o das cargas el\u00e9tricas das duas esferas\u00a0<\/b><\/span><\/span><\/span>no ponto M<\/b><\/span><\/span><\/span>.<\/b><\/span><\/span><\/span><\/p>\n

Trabalho da For\u00e7a El\u00e9trica<\/b><\/span><\/span><\/span><\/p>\n

13-Escola Naval 2018\/2019<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Analise a figura abaixo<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Na figura acima, a linha pontilhada mostra\u00a0<\/b><\/span><\/span><\/span>a trajet\u00f3ria plana de uma part\u00edcula de carga -q = -3,0 C que percorre 6,0 metros, ao se deslocar do ponto A, onde estava em repouso, at\u00e9 o ponto B, onde foi conduzida novamente ao repouso.\u00a0<\/b><\/span><\/span><\/span>Nessa regi\u00e3o do espa\u00e7o, h\u00e1 um\u00a0<\/b><\/span><\/span><\/span>campo el\u00e9trico conservativo,\u00a0<\/b><\/span><\/span><\/span>cujas superf\u00edcies equipotenciais est\u00e3o representadas na figura.\u00a0<\/b><\/span><\/span><\/span>Sabe-se que, ao longo desse deslocamento da part\u00edcula, atuam somente duas for\u00e7as sobre ela, onde uma delas \u00e9 a for\u00e7a externa, Fext.\u00a0<\/b><\/span><\/span><\/span>Sendo assim, qual o trabalho, em quilojoules, realizado pela for\u00e7a Fext\u00a0no deslocamento da part\u00edcula do ponto A at\u00e9 o ponto B?<\/b><\/span><\/span><\/span><\/p>\n

(A) -0,28<\/b><\/span><\/span><\/span><\/p>\n

(B) +0,28<\/b><\/span><\/span><\/span><\/p>\n

(C) -0,56<\/b><\/span><\/span><\/span><\/p>\n

(D) +0,56<\/b><\/span><\/span><\/span><\/p>\n

(E) -0,85<\/b><\/span><\/span><\/span><\/p>\n

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

<\/p>\n

\u00a0Apenas \u00e9 correto\u00a0<\/b><\/span><\/span><\/span>o que se\u00a0<\/b><\/span><\/span><\/span>afirma<\/b><\/span><\/span><\/span>\u00a0em<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

15-(AFA-017\/018)<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

Come\u00e7ou a temporada de raios e o Brasil \u00e9 o lugar onde eles mais caem no mundo.<\/b><\/span><\/span><\/span><\/p>\n

Os raios s\u00e3o fen\u00f4menos da natureza impressionantes, mas causam mortes e preju\u00edzos. Todos os anos morrem em m\u00e9dia 130 pessoas no pa\u00eds atingidas por essas descargas el\u00e9tricas. (\u2026) (\u2026) Segundo as pesquisas feitas pelo grupo de eletricidade atmosf\u00e9rica<\/b><\/span><\/span><\/span><\/p>\n

\"ELETROST\u00c1TICA\"<\/p>\n

do INPE, o n\u00famero de mortes por raios \u00e9 maior do que por deslizamentos e enchentes. E \u00e9 na primavera e no ver\u00e3o, \u00e9poca com mais tempestades, que a preocupa\u00e7\u00e3o aumenta (\u2026)<\/b><\/span><\/span><\/span><\/p>\n

(Dispon\u00edvel em: ww1.g1.globo.com\/bom-dia-brasil. Acesso em:16 fev.2017)<\/b><\/span><\/span><\/span><\/p>\n

Como se pode verificar na\u00a0<\/b><\/span><\/span><\/span>not\u00edcia acima,\u00a0<\/b><\/span><\/span><\/span>os raios causam mortes e,\u00a0<\/b><\/span><\/span><\/span>al\u00e9m disso<\/b><\/span><\/span><\/span>, constantemente h\u00e1 outros preju\u00edzos ligados a eles:\u00a0<\/b><\/span><\/span><\/span>destrui\u00e7\u00e3o de linhas de transmiss\u00e3o de energia e telefonia, inc\u00eandios florestais, dentre outros.<\/b><\/span><\/span><\/span><\/p>\n

As nuvens se eletrizam devido \u00e0s\u00a0<\/b><\/span><\/span><\/span>part\u00edculas de gelo\u00a0<\/b><\/span><\/span><\/span>que come\u00e7am a\u00a0<\/b><\/span><\/span><\/span>descer muito rapidamente,\u00a0<\/b><\/span><\/span><\/span>criando correntes de ar bastante bruscas, o que\u00a0<\/b><\/span><\/span><\/span>provoca\u00a0<\/b><\/span><\/span><\/span>fric\u00e7\u00e3o\u00a0<\/b><\/span><\/span><\/span>entre\u00a0<\/b><\/span><\/span><\/span>gotas de \u00e1gua e de gelo,\u00a0<\/b><\/span><\/span><\/span>respons\u00e1vel pela\u00a0<\/b><\/span><\/span><\/span>forma\u00e7\u00e3o e, consequentemente,\u00a0<\/b><\/span><\/span><\/span>a\u00a0<\/b><\/span><\/span><\/span>acumula\u00e7\u00e3o de eletricidade est\u00e1tica.<\/b><\/span><\/span><\/span><\/p>\n

Quando se acumula carga el\u00e9trica negativa demasiadamente na zona inferior da nuvem (este \u00e9 o caso mais comum)\u00a0<\/b><\/span><\/span><\/span>ocorre uma\u00a0<\/b><\/span><\/span><\/span>descarga el\u00e9trica em dire\u00e7\u00e3o ao solo (que por indu\u00e7\u00e3o eletrost\u00e1tica adquiriu cargas positivas).<\/b><\/span><\/span><\/span><\/p>\n

Considere que a base de uma nuvem de tempestade, eletricamente carregada com\u00a0<\/b><\/span><\/span><\/span>carga de m\u00f3dulo igual a 2,0\u00a0<\/b><\/span><\/span><\/span>\u22c5<\/b><\/span><\/span><\/span>10\u00b2 C ,<\/b><\/span><\/span><\/span>\u00a0situa-se a\u00a0<\/b><\/span><\/span><\/span>500 m acima do solo.<\/b><\/span><\/span><\/span><\/p>\n

O ar\u00a0<\/b><\/span><\/span><\/span>mant\u00e9m se\u00a0<\/b><\/span><\/span><\/span>isolante<\/b><\/span><\/span><\/span>\u00a0at\u00e9 que o\u00a0<\/b><\/span><\/span><\/span>campo el\u00e9trico entre a base da nuvem e o solo atinja o valor de 5,00<\/b><\/span><\/span><\/span>\u22c5<\/b><\/span><\/span><\/span>106\u00a0V\/m.<\/b><\/span><\/span><\/span><\/p>\n

Nesse instante a nuvem se\u00a0<\/b><\/span><\/span><\/span>descarrega\u00a0<\/b><\/span><\/span><\/span>por meio de um\u00a0<\/b><\/span><\/span><\/span>raio que dura 0,10 s.\u00a0<\/b><\/span><\/span><\/span>Considerando que\u00a0<\/b><\/span><\/span><\/span>o\u00a0<\/b><\/span><\/span><\/span>campo el\u00e9trico<\/b><\/span><\/span><\/span>\u00a0na regi\u00e3o onde ocorreu o raio\u00a0<\/b><\/span><\/span><\/span>seja uniforme,\u00a0<\/b><\/span><\/span><\/span>a\u00a0<\/b><\/span><\/span><\/span>energia liberada neste raio \u00e9, em joules, igual\u00a0<\/b><\/span><\/span><\/span>a<\/b><\/span><\/span><\/span><\/p>\n

<\/p>\n

 <\/p>\n

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

Vestibulares Recentes ELETRICIDADE \u2013 2018\/2019 ELETROST\u00c1TICA \u2013 2018\/2019 Carga el\u00e9trica e processos de eletriza\u00e7\u00e3o 01-Col\u00e9gio Naval 2018\/2019 Sobre\u00a0eletricidade\u00a0e\u00a0magnetismo\u00a0analise as afirmativas abaixo e assinale a op\u00e7\u00e3o que apresenta o\u00a0conceito INCORRETO. (A) Part\u00edculas ou corpos com\u00a0cargas el\u00e9tricas\u00a0de\u00a0sinais iguais\u00a0se\u00a0repelem\u00a0e com\u00a0sinais diferentes\u00a0se\u00a0atraem. (B) Um corpo \u00e9 dito\u00a0neutro\u00a0quando possui\u00a0igual quantidade de pr\u00f3tons e el\u00e9trons. (C) Um corpo \u00e9 dito\u00a0eletrizado positivamente\u00a0quando inicialmente\u00a0neutro, por algum processo de<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":3299,"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-4843","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4843","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=4843"}],"version-history":[{"count":4,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4843\/revisions"}],"predecessor-version":[{"id":9911,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/4843\/revisions\/9911"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/3299"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=4843"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}