Estática - Introdução Teórica
Autor: CEM Arizinho - Física - Profª Sabrinna | Publicado: 2012-11-06T01:33:00-08:00


Bom dia!



Abaixo está a introdução teórica sobre Estática, em forma de Estudo Dirigido - Capítulo 5. Lembrando que já fizemos em sala diversos exercícios sobre Equilíbrio, Torque, Centro de Massa e Centro de Gravidade.

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1)&nbsp;&nbsp;&nbsp; O que determina o giro de um objeto? 

O ponto de
aplicação das forças.



2)&nbsp;&nbsp;&nbsp; O que é um sistema binário, quando falamos de Torque?

É um par de
forças contrárias.



3)&nbsp;&nbsp;&nbsp; O torque está relacionado à que?

Ao módulo
da força aplicada no objeto e com a distância do ponto de aplicação até o eixo.



4)&nbsp;&nbsp;&nbsp; O que é braço da força? Faça também um desenho
explicativo.

É a distância
do ponto de aplicação até o eixo. Ex.: porta.



5)&nbsp;&nbsp;&nbsp; Qual é a expressão matemática do Torque?

T = F. b



6)&nbsp;&nbsp;&nbsp; Qual é a unidade de medida do Torque, no SI?

N.m



7)&nbsp;&nbsp;&nbsp; Explique o que é a Regra da Mão Direita e para quê serve?

O polegar
indica a direção do torque (paralelo ao eixo) e os dedos a direção de rotação.
Serve para definir a direção e o sentido de rotação dos objetos.



8)&nbsp;&nbsp;&nbsp; Quando é que não ocorre rotação de objetos?

Quando as
forças e os torques resultantes nulos.



9)&nbsp;&nbsp;&nbsp; Como podemos aumentar o torque?

Aplicando a
força o mais longe possível do eixo de rotação.



10) Defina: força resistente e força potente.

Força
resistente: aquela que o parafuso aplica na ferramenta, por exemplo.

Força
potente: aquela que a mão aplica na ferramenta, por exemplo.



11) Como definimos vantagem mecânica:

a)&nbsp;&nbsp;
Usando forças à
VM=Fr/Fp

Fr – força
resistente // Fa ou Fp – força potente.



b)&nbsp;&nbsp;
Usando o conceito de
Torque
à VM = b/r

b – ponto
de aplicação da força (pela mão)

r – força
aplicada pela ferramenta sobre o objeto (pode ser o raio de uma porca, por
exemplo).