Sabendo que a diferença de potencial entre uma nuvem e a Terra, para que aconteça a descarga elétrica de um raio, é em torno de !$ 3 . 10^8 !$ V e que a corrente elétrica produzida neste caso é aproximadamente de !$ 1 . 10^5 !$ A, qual a resistência média do ar, em ohms (!$ Ω !$)?

O vidro tem índice de refração absoluto igual a 1,5. Sendo a velocidade da luz no ar e no vácuo aproximadamente igual a !$ 3.10^8 !$ m/s, pode-se calcular que a velocidade da luz no vidro é igual a

A Region’s Soccer Strongmen are facing a hard fall

After rising as a governor under Brazil’s military dictatorship, José Maria Marin became such a towering figure in the world of Brazilian sports that the headquarters of the nation’s soccer federation was recently named in his honor.

Now, the United States Justice Department’s charging Mr. Marin, 83, and 13 other senior sports officials and executives across the Americas with taking part in a sweeping bribery and kickback scheme within FIFA, the governing body of global soccer.

Of the 14 men named as defendants in the indictment, all but two of them are citizens of Latin American and Caribbean nations, a reflection of the investigation’s focus on corruption in the hemisphere.

(Fonte: www.nytimes.com)

GLOSSARY
but: exceto
bribery: suborno
headquarters: sede

All the extracts below, in the text, present a possessive noun, except:

Um aluno da Escola de Especialistas de Aeronáutica que participaria de uma instrução de rapel ficou impressionado com a altura da torre para treinamento. Para tentar estimar a altura da torre, fincou uma haste perpendicular ao solo, deixando-a com 1 m de altura. Observou que a sombra da haste tinha 2 m e a sombra da torre tinha 30 m. Desta forma, estimou que a altura da torre, em metros, seria de:

The story of a blind girl

There was a blind girl who hated herself just because she was blind. She hated everyone, except her loving boyfriend. He was always there for her. She said that if she could only see the world, she would marry her boyfriend.

One day, someone donated a pair of eyes to her and then she could see everything, including her boyfriend. Her boyfriend asked her, “Now that you can see the world, will you marry me?”

The girl was shocked when she saw that her boyfriend was blind too, and refused to marry him. Her boyfriend walked away in tears, and later wrote a letter to her saying: “Just take care of my eyes dear.”

Fonte: http://academictips.org/

According to the text, all the alternatives are true, except

Uma bateria de 9 V tem resistência interna de 0,1 !$ Ω !$ . Assinale a opção que indica o valor da sua corrente de curto-circuito, em ampères.

Duas cordas se cruzam num ponto distinto do centro da circunferência, conforme esboço. A partir do conceito de ângulo excêntrico interior, a medida do arco x é

Uma hélice de avião gira a 2800 rpm. Qual a frequência (f) de rotação da hélice, em unidades do Sistema Internacional (SI)? Adote !$ \pi !$ !$ \cong !$ !$ 3 !$.