Uma corda é composta de dois segmentos de densidades de massa bem distintas. Um pulso é criado no segmento de menor densidade e se propaga em direção à junção entre os segmentos, conforme representa a figura abaixo.

Assinale, entre as alternativas, aquela que melhor representa a corda quando o pulso refletido está passando pelo mesmo ponto x indicado no diagrama acima.

(UERJ) A palavra “imperialismo”, no sentido moderno, desenvolveu-se primordialmente na língua inglesa, sobretudo depois de 1870. Seu significado sempre foi objeto de discussão, à medida que se propunham diferentes justificativas para formas de comércio e de governo organizados. Havia, por exemplo, uma campanha política sistemática para equiparar imperialismo e “missão civilizatória”. 

Adaptado de WILLIAMS, Raymond. Um vocabulário de cultura e sociedade.São Paulo: Boitempo, 2007.

Uma das ações empreendidas pelos europeus como missão civilizatória nessas regiões foi:

No final do século XIX, os europeus defendiam seus interesses imperialistas nas regiões africanas e asiáticas, justificando-os como missão civilizatória.

Analise as figuras a seguir e o que se pede na questão

Em muitas situações da vida atual, encontramos a presença do alfabeto braile, que possibilita a leitura das pessoas que possuem forte deficiência visual. 

Explique por que é importante o uso do alfabeto braile na sociedade atual

UNEP-SEFI. Global trends in justainable energy investiment, 2009. Nota: Investimentos e variações da Coreia do Sul referem-se a 2008-2009.

 A figura acima ilustra o crescimento de investimentos na produção de biocombustíveis em várias partes do mundo. Tendo como referência essa figura, bem como os múltiplos aspectos que ela envolve, julgue o item subsequente.

No Brasil, uma das restrições à expansão da produção de biocombustíveis, como no caso do etanol, é o fato de, cada vez mais, a demanda estar concentrada em grandes cidades.

 How working together can help keep kids safe from digital dangers

Carol Todd remembers a time when teenagers’ insults were written on the bathroom wall or a piece of paper and could be washed away or torn to shreds. It was a time when bullying was a schoolyard event, when the trials and tribulations of adolescence stopped at your bedroom door and that room was a refuge from the outside world.

No more. Now bullying has become a wider and more enduring problem through the use of technology and social media, says Todd. “Something physical or face-to-face could happen at school and then they come home, turn on their devices and, boom, it’s right there – pictures, videos, words, the story. And it isn’t just one-to-one anymore. It’s oneto-100,000.”

Todd knows all too well how difficult growing up in the digital age can be. Her daughter Amanda was subjected to relentless online bullying, extortion and public humiliation by a suspected perpetrator based in the Netherlands. She was just 16 and could not resist the humiliation.

Todd, a teacher by profession, has since devoted her time and her skills to educating the public about online safety and security through her foundation, the Amanda Todd Legacy Society, as well as through her involvement in a free education program called Wise Internet and Smartphone Education.

Cyberbullying, says Todd, is not only a youth problem. It can affect everyone, from youngsters to the elderly. Nearly 75 per cent of American adults have witnessed online persecution, with 40 per cent having personally experienced cyberbullying, according to a survey on the subject by the Pew Research Center.

“This is a global phenomenon that’s happening to people of all ages,” Todd says.

But youngsters seem to be more vulnerable. The reality is that 90 per cent of young people have some form of Internet-connected device and most have multiple social media accounts. Kids today may be tech savvy, says Todd, but they are no different from what kids have always been like – just as curious, adventurous, naive and vulnerable. “Kids are kids,” says Todd. “They are no different now. It’s just that now they’ve got a tool in their hands that can be just as dangerous as a car.” 

“When your child turns 16, you don’t give the car keys to them and tell them to go drive as long as they want. You give them lessons; you make sure they’re safe. We should be doing the same thing with mobile devices like smartphones and tablets.”

Don’t lecture, she urges parents. And don’t be quick to punish mistakes. “The keys are communication and trust,” she says. “Parents and their kids need to have open conversations – conversations without judgment.”

Source: <http://news.nationalpost.com/inspire-us/how-working-together-can-help-

keep-kids-safe-from-digital-dangers?__lsa=dc27-7d6a>. Adapted.

Vocabulary:

Perpetrator – a person who commits an illegal, criminal, or evil act.

Savvy – experienced and well-informed.

According to Carol Todd