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Use os filtros para chegar às questões que interessam. Cada resultado abre em uma página própria com enunciado, alternativas e gabarito.
Um vídeo postado na internet no 1o dia do ano obteve, nesse dia (t=1), 800 likes e 100 dislikes.
Estima-se que nos próximos dias (t = 2, 3, 4, ...) haverá um aumento diário de 10% nos likes acumulados e um aumento diário de 4,5% nos dislikes acumulados. Tais estimativas são válidas até o momento em que a razão entre dislikes e likes seja aproximadamente 1/40, o que ocorrerá no valor inteiro de t mais próximo de
A testosterona é o principal hormônio masculino, responsável por desenvolver e manter as características masculinas. A figura abaixo representa a estrutura da testosterona.
A sua fórmula molecular é
Por que o biogás é uma opção de energia renovável?
O biogás é um biocombustível gasoso produzido a partir da decomposição da matéria orgânica por bactérias fermentadoras, em um processo chamado biodegradação anaeróbia, isto é, o processo ocorre na ausência de oxigênio. Nesse processo, produz-se um gás rico em metano (de 40% a 80% de sua composição, sendo o resto dióxido de carbono e pequenas quantidades de hidrogênio, nitrogênio, amônia, ácido sulfídrico, entre outros). Para gerar energia elétrica usando biogás, utiliza-se a conversão da energia química do gás em energia mecânica, por meio de um processo controlado de combustão, que ativa um gerador. O biogás também pode ser purificado para a geração de biometano, que é equivalente ao gás natural veicular.
A tabela a seguir compara as composições químicas médias dos principais componentes do biogás e do biometano.
Gás Principais componentes (% em volume)
Biogás 60% metano; 40% dióxido de carbono
Biometano 95% metano; 5% dióxido de carbono
Pelota valenciana: un deporte olímpico
Josué Ferrer
A figura mostra duas partículas A e B de massas respectivamente iguais a mA e mB e cargas elétricas qA e qB. Considere que elas estão sujeitas exclusivamente às forças eletrostáticas mútuas devidas às suas cargas e que as setas na figura representam suas respectivas acelerações vetoriais:
Comparando as cargas e as massas das partículas,
conclui-se que
A figura representa um aspecto da República Velha brasileira,
mais especificamente a República Oligárquica. A crítica
presente na figura remete
Born on April 15, 1452, in Vinci, Italy, Leonardo da Vinci was the son of a prominent attorney notary and a young peasant girl. Born out of wedlock, he was raised by his father, Ser Piero, and several stepmothers.
His early years were spent living on his father’s family estate in Vinci. Beyond basic reading, writing and mathematical skills, da Vinci did not receive much of a formal education. Recognizing his potential as an artist, his father sent him at the age of 14 or 15 to apprentice with sculptor and painter Andrea del Verrocchio of Florence.
He spent six years honing his technical skills, including metalworking, leather arts, carpentry, drawing and sculpting, and became a member of the Guild of Saint Luke by the age of 20. He remained with Verrocchio until he became an independent master in 1478. Around that time, he took on his first commissioned work, The Adoration of the Magi, for Florence’s San Donato, a Scopeto monastery, but departed for Milan the following year, leaving the painting unfinished. It has been in the Uffizi Gallery in Florence since 1670.
Leonardo was, and is, renowned primarily as a painter. Among his works, the Mona Lisa is the most famous and most parodied portrait and The Last Supper the most reproduced religious painting of all time, with their fame approached only by Michelangelo's The Creation of Adam. Leonardo's drawing of The Vitruvian Man, based on the correlations of ideal human proportions with geometry described by the ancient Roman architect Vitruvius, is also regarded as a cultural icon, being reproduced on items as varied as the euro coin, textbooks, and T-shirts.
Leonardo is also revered for his technological ingenuity. In the early 1490s, he began chronicling his thoughts about painting, architecture, mechanics and human anatomy. These notebooks contained wide-ranging ideas, including plans for a “flying machine,” bicycle and drawings of a fetus in the womb and the human skeleton.
His interests and intellect traversed so many disciplines that he symbolized the term “Renaissance Man”. Unfortunately, these notebooks were not published and his ideas did not advance scientific understanding in the Renaissance period.
Today, Leonardo is widely recognized as one of the most diversely talented individuals ever to have lived.
(Adapted form: http://www.livescience.com/39355-leonardo-da-vinci.html)
Leia atentamente a tirinha a seguir para responder à questão.
Fonte: SARMENTO, Leila Lanar. Português: literatura, gramática, produção de texto. São Paulo: Moderna, 2010.
Nos anos 30, assume a presidência da república dos EUA, Franklyn Delano Roosevelt. Sua principal realização no período da depressão é um plano econômico elaborado de conformidade com o economista britânico John Maynard Keynes, denominado New Deal (Novo Acordo), visando reduzir os efeitos da crise.
Disponível em: <http://www.novosolhos.com.br/download.php?extensao=pdf&original=A%20GRANDE%20DEPRESS %C3%83O%20-%20%20GAETA.pdf&servidor=arq_material/934_1000.pdf>Acesso em: 19 jun. 2014.
As ações promovidas pelo New Deal dão início a uma política
econômica claramente contrária
Born on April 15, 1452, in Vinci, Italy, Leonardo da Vinci was the son of a prominent attorney notary and a young peasant girl. Born out of wedlock, he was raised by his father, Ser Piero, and several stepmothers.
His early years were spent living on his father’s family estate in Vinci. Beyond basic reading, writing and mathematical skills, da Vinci did not receive much of a formal education. Recognizing his potential as an artist, his father sent him at the age of 14 or 15 to apprentice with sculptor and painter Andrea del Verrocchio of Florence.
He spent six years honing his technical skills, including metalworking, leather arts, carpentry, drawing and sculpting, and became a member of the Guild of Saint Luke by the age of 20. He remained with Verrocchio until he became an independent master in 1478. Around that time, he took on his first commissioned work, The Adoration of the Magi, for Florence’s San Donato, a Scopeto monastery, but departed for Milan the following year, leaving the painting unfinished. It has been in the Uffizi Gallery in Florence since 1670.
Leonardo was, and is, renowned primarily as a painter. Among his works, the Mona Lisa is the most famous and most parodied portrait and The Last Supper the most reproduced religious painting of all time, with their fame approached only by Michelangelo's The Creation of Adam. Leonardo's drawing of The Vitruvian Man, based on the correlations of ideal human proportions with geometry described by the ancient Roman architect Vitruvius, is also regarded as a cultural icon, being reproduced on items as varied as the euro coin, textbooks, and T-shirts.
Leonardo is also revered for his technological ingenuity. In the early 1490s, he began chronicling his thoughts about painting, architecture, mechanics and human anatomy. These notebooks contained wide-ranging ideas, including plans for a “flying machine,” bicycle and drawings of a fetus in the womb and the human skeleton.
His interests and intellect traversed so many disciplines that he symbolized the term “Renaissance Man”. Unfortunately, these notebooks were not published and his ideas did not advance scientific understanding in the Renaissance period.
Today, Leonardo is widely recognized as one of the most diversely talented individuals ever to have lived.
(Adapted form: http://www.livescience.com/39355-leonardo-da-vinci.html)
Leia atentamente a tirinha a seguir para responder à questão.
Fonte: SARMENTO, Leila Lanar. Português: literatura, gramática, produção de texto. São Paulo: Moderna, 2010.
Uma amostra de água mineral natural a 25 °C foi testada com três indicadores ácido-base. Os resultados desse teste estão indicados na última coluna da tabela.
Analisando as informações da tabela e sabendo que o
produto iônico da água a 25 °C, Kw, é igual a 1 × 10−14, a
concentração de íons OH− (aq) nessa água mineral, em
mol/L, está entre
