Uma onda estacionária é estabelecida em uma corda homogênea de comprimento  presa pelas extremidades, A e B, conforme figura abaixo.

Considere que a corda esteja submetida a uma tensão de 10 N e que sua densidade linear de massa seja igual a 0,1 kg/m.Nessas condições, a opção que apresenta um sistema massa-mola ideal, de constante elástica K, em N/m e massa m, em kg, que oscila em movimento harmônico simples na vertical com a mesma frequência da onda estacionária considerada é:

Na década passada, a demanda por determinadas mercadorias aumentou muito, puxada, principalmente, pelo crescimento acelerado da China. Isso influenciou os preços, que ficaram mais altos e favoreceu os países produtores. Foi um período de bom crescimento do PIB brasileiro, mesmo com a crise mundial de 2008. A atual queda em seus preços globais começou com a desaceleração da China, por volta de 2011. O país asiático vive um processo de transição para um novo modelo econômico, que valoriza o mercado interno em detrimento da produção industrial para exportação.

(www.nexojornal.com.br. Adaptado.)

De grande importância para a economia brasileira, as mercadorias, negociadas globalmente, a que o excerto se refere correspondem a

(UECE) Uma pilha (1,5 V) e um resistor (1,5 Ω), são conectados um ao outro por apenas um de seus terminais durante o experimento I. Em outro experimento, o experimento II, os dois terminais da bateria são conectados aos terminais do resistor.

A diferença de potencial elétrico e a corrente no resistor são, respectivamente,

(PUC-RIO) Are You A Digital Native or A Digital Immigrant?

We all know that we are living in an increasingly technologically driven world. Living here in the heart of Silicon Valley I certainly feel it every day. In fact, I don’t think I know a single couple in my neighborhood, other than my wife and I, who don’t work in the technology field in some capacity. Our local companies are Facebook, Apple, Google, Yahoo, and so many venture capital firms that I can’t keep them straight. But you don’t have to live in Silicon Valley to feel that the world is getting more and more technology centered, focused, and driven. We can debate the pros and cons of this reality but ⁹we can’t deny that the world has changed very quickly in head spinning ways. Two recent comments led me to finally enter the 21^st century ²by getting a smart phone this week, kicking and screaming.

First, I mentioned to one of my undergraduate classes at Santa Clara University that I didn’t have a smart phone, but rather I had a ⁸dumb phone. ¹⁰My phone can make and receive phone calls and that’s about it. No email, internet, and so forth. ³So one of my students looked at me in an odd and curious way, like she was talking to someone from another planet, and stated in ¹¹a matter of fact manner, “Professor Plante, even 2^nd graders have smart phones.” Ouch!

Second, ⁴I was talking with a producer at the PBS NewsHour who wanted me to do a live interview within a few hours of his call regarding some late breaking news about clergy sexual abuse, which is my specialty. I was out of the office and driving my car when he called and in ¹²a matter of fact manner he said that he wanted to send me some important information to my smart phone to best prepare me for the upcoming interview. When I told him that I couldn’t receive anything since I had a dumb phone and not a smart phone, there was a long silence. ¹He then said he’d have to just read it to me over the phone as a Plan B. He wasn’t happy ... neither was I.

⁷In case you haven’t noticed, the 21^st century is really upon us and to live in it one really does need to be connected in my view. Although I often consider myself a 19^th or 20^th century guy trapped in the 21^st century we really do need to adapt. For most of us we are just living in a new world that really demands comfort with and access to technology.

This notion of digital native vs. digital immigrant makes a great deal of sense to me. Young people in our society are digital natives. They seem to be very comfortable with everything from iPhones to TV remotes. Digital immigrants, like me, just never feel that comfortable with these technologies. Sure we may learn to adapt by using email, mobile phones, smart ones or dumb ones, Facebook, and so forth but it just doesn’t and perhaps will never be very natural for us. It is like learning a second language ... you can communicate but with some struggle.

This has perhaps always been true. I remember when I was in graduate school in the 1980s trying to convince my grandparents that buying a telephone answering machine as well as a clothes dryer would be a good idea. They looked at me like I was talking in another language or that I was from another planet.

⁵Perhaps we have a critical period in our lives for technology just like we do for language. ⁶When we are young we soak up language so quickly but find it so much harder to learn a new language when we are older. The same seems to be true for technology.

So, this week I bought my first smart phone and am just learning to use it. When questions arise, I turn to my very patient teenage son for answers. And when he’s not around, I just look to the youngest person around for help.

So, what about you? Are you a digital native or a digital immigrant and how does it impact your life?Adapted from “Digital Native vs. Digital Immigrant? Which are you?”

            Published on July 24, 2012 by Thomas G. Plante, Ph.D., ABPP in Do the Right Thing http://www.psychologytoday.com/blog/do-the-right-thing/201207/digital-native-vs-digital-immigrant-which-are-you retrieved on July 28, 2012

“We can’t deny” in “...we can’t deny that the world has changed very quickly...” (ref. 9) and “My phone can make” in “My phone can make and receive phone calls...” (ref. 10) express the ideas of, respectively:

" Fotografar é uma maneira de registrar para sempre um momento, um lugar, uma lembrança. Além disso, é também uma forma de expressão. Por meio da fotografia podemos conhecer o modo como o fotógrafo vê e se comunica com o mundo."

• Professor, peça aos alunos para fazerem uma reflexão sobre o texto acima.
• À partir desta reflexão, o professor vai falar também sobre os elementos que são necessários no momento que vamos fotografar. Falar sobre a importância da luz, do enquadramento, do ângulo, da composição, dos planos, focos, entre outros.
• Disponível: http://ozhernandez.blogspot.com.br/2015/04/elementos-visuais-da-linguagem.html
• A proposta para esta aula é fazer uma experimentação de uma composição usando a luz de um retroprojetor.
• O professor vai separar a sala em grupos de até 04 alunos.
• Cada grupo vai montar uma composição bem bonita, dentro da tampa da caixa de sapato, utilizando os objetos de plástico.
• Com a luz da sala apagada e o retroprojetor ligado, os alunos vão colocar as composições que foram montadas sobre o retroprojetor. A imagem resultante será projetada na parede.
• Peça aos alunos para afastar e aproximar a composição do retroprojetor e observar o que acontece com a imagem.
• Peça aos alunos para fotografar as imagens projetadas.
• Revelar as fotos.

     Fonte: Ápis – Arte – Eliana Pougy Ensino Fundamental Anos Iniciais – Manual do professor Página 304