(UCS) Special delivery

The other day in our mailbox there was a letter from Auntie Anne. She is nearing 80 and does not know how important Facebook has become. She is not interested in Twittering and does not see the use of Internet. She is addicted to pen and paper.

Every other week for the past 30 years I have sat down and written a letter to her. I started writing to her when I was 10 and she was living at Lake Ranch in the interior of British Columbia. Her letters were full of what Uncle Willi was doing. He was a cowboy and he rode quarter horses every day, moving cattle and watching out for rattle-snakes.

Her correspondence was like a novel ¹whose main characters were my family, and I still have every letter. My letters were full of school in Victoria and family and ballet. I learned to ²pack mine with ³whatever I thought was important. She would write back with questions and slowly I learned how to tell a story. I also learned about the paraphernalia of letter writing, keeping my address book current, having a ready supply of paper, envelopes and stamps.

I caught the letter-writing bug myself. While still home in Victoria and studying at university, I wrote to friends who were studying and living in France and China. We shared our ⁴hopes and travels, and chronicled our love lives. I have boxes filled with their letters.

Once graduated from university, I packed my backpack and traveled around the world. My letters reached Auntie Anne from Asia and Europe. Places she had never seen, but ⁷was keen to hear all about. When ⁸I was homesick, letters from my family would find me everywhere and I would feel like the world was smaller. Someone out there cared.

Nowadays most wired people muse that ⁹snail mail is not all that relevant any more. Nobody uses the mail these days, they say. When was the last time someone ⁵actually wrote a letter? But what about postcards when you travel? What about the small businesses who rely on cheques in the mail? What about all those charities needing funds to carry on? What about all those things you order online? Who makes them come right to your door?

Now that the kids are out of school it seems the perfect time to get them to write to Auntie Anne. I coach them on the rules of writing to her. She does not like fancy paper any more. She thinks it is better to recycle a flyer from the mailbox or the back of the newsletter from my daughter´s preschool. We need to always use the formal salutation “dear” and formal closing “love”, because being dear to someone and telling them we love them is what we all want to get in the mail.

Auntie Anne always includes a note for each child with questions of their own to answer in a letter back to her. They usually carry her notes around and use them for bookmarkers for days afterward or dance around holding the letter in their hands.

I keep an addressed envelope on the kitchen counter ready in case I see a clipping from the newspaper I know Auntie Anne will be interested in, or a nice bit of artwork from the children or perhaps even a note written by them.

¹⁰As I mail my ⁶parcel to Auntie Anne, perhaps in the next week or so we will receive another letter from her. Because if we want a letter, we must first write one.

(KOVACH, P. R. Special delivery. The globe and the mail, Canada, July 12, 2011. – Texto adaptado.) 

É possível afirmar que o segmento As I mail my parcel to Auntie Anne... (ref. 10) encerra a ideia de

A distância  indicada na figura:

Um corpo de carga positiva, inicialmente em repouso sobre uma rampa plana isolante com atrito, está apoiado em uma mola, comprimindo-a. Após ser liberado, o corpo entra em movimento e atravessa uma região do espaço com diferença de potencial sendo acelerado. Para que o corpo chegue ao final da rampa com velocidade nula, a distância  indicada na figura é:

Dados:

- deformação inicial da mola comprimida: X

- massa do corpo: m

- carga do corpo: +Q

- aceleração da gravidade: g

- coeficiente de atrito dinâmico entre o corpo e a rampa:

- ângulo de inclinação da rampa:

- constante elástica da mola: K

Considerações:

- despreze os efeitos de borda;

- a carga do corpo permanece constante ao longo da trajetória. 

Dois atletas partem de pontos, respectivamente P1 e P2, em duas pistas planas distintas, conforme a figura, deslocando-se no sentido anti-horário até a linha de chegada, percorrendo, desta forma, a mesma distância (L). Os trechos retos dos finais das curvas até a linha de chegada desse percurso têm o mesmo comprimento (l) nas duas pistas e são tangentes aos trechos curvos, que são semicírculos de centro C. O raio do semicírculo maior é R1 e o raio do semicírculo menor é R2.

Sabe-se que o comprimento de um arco circular é dado pelo produto do seu raio pelo ângulo, medido em radiano, subentendido pelo arco.

Nas condições apresentadas, a razão da medida do ângulo pela diferença L− l é dada por

(UTFPR) Em 2015 realizou-se uma conferência mundial (Conferência de Paris) para debater sobre o aquecimento global e a redução do efeito estufa. Entre os principais gases causadores destes problemas estão CO₂, CO, NO₂, NO, SO_2, que através de diferentes mecanismos podem levar ao aquecimento global, chuva ácida e à destruição da camada de O₃, ozônio. 

A respeito do tema, assinale a alternativa correta.

(Unipê)

A ilustração representa, de forma simplificada, um importante processo associado à atividade do material genético celular.

Com base nessa imagem e nos conhecimentos atuais a respeito desse assunto, é correto afirmar: