Foram encontradas 118 questões.
Um professor quer verificar se um objeto maciço e de massa “m” é feito unicamente de uma determinada substância de densidade dO. Para isso, pendurou uma mola, que obedece a Lei de Hooke, na vertical por uma das suas extremidades e na outra colocou o objeto. Em seguida, o professor mediu o módulo da força elástica (!$ F_1 !$) que a mola exerce sobre o objeto devido ao alongamento !$ \Delta x1 !$(considere que a mola e o objeto estão em equilíbrio estático e no ar, cujo empuxo sobre o objeto e a mola é desprezível). Ainda com a mola e o objeto na vertical, conforme o desenho, o professor mediu o novo módulo da força elástica, agora chamada de !$ F_2 !$, que a mola exerce sobre o objeto devido ao alongamento !$ \Delta x2 !$, considerando o objeto em equilíbrio estático e totalmente imerso na água (densidade d!$ _A !$). Considere também que a experiência toda foi realizada em um local onde o módulo da aceleração da gravidade (g) é constante e que o empuxo da água sobre a parte imersa da mola é desprezível.
Para que objeto seja feito unicamente da substância com densidade !$ d_O !$ prevista, !$ F_2 !$ deve ser
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Southwest Airlines Flight 1380
Jeremy Berke
Southwest Airlines Flight 1380 suffered an engine failure that smashed a plane window, sucking a passenger halfway out of the plane in midair.
A passenger on a Southwest Airlines flight on Tuesday was partially sucked out of a window after an engine exploded in midair.
The flight, traveling from New York to Dallas, was forced to make an emergency landing in Philadelphia, and the passenger — a 43-year-old woman named Jennifer Riordan — died Tuesday at a hospital. It was the first fatality in a US passenger plane accident in nine years.
Passengers on the flight described how, after the explosion sent shrapnel into one of the plane’s windows, Riordan was pulled halfway out of aircraft.
While passengers were able to pull Riordan back into the plane, another passenger was said to have felt “severe pressure” after positioning his back against the opening in the cabin in an attempt to seal it.
When there’s an opening in an airplane during flight (regardless of the cause), the plane will undergo rapid depressurization.
Adapted from http://www.businessinsider.com
In, “... another passenger was said to have felt severe pressure after positioning his back against the opening in the cabin in an attempt to seal it”.
The word “seal” is closest in meaning to ____________.
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Uma espira circular com 6,28 cm de diâmetro é percorrida por uma corrente elétrica de intensidade igual a 31,4 mA e, nessas condições, produz um vetor campo magnético no centro dessa espira com uma intensidade no valor de ______ !$ \times 10^{-7} !$T.
Considere a permeabilidade magnética no vácuo,
!$ μ_0 = 4 \pi \cdot 10 ^{-7} {\large T \cdot m \over A} !$
e utilize !$ \pi = 3,14 !$.
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Mrs. Pratchett
Her name was Mrs Pratchett. She was a small, skinny old hag with moustache on her upper lip and a mouth as sour as a green goosebery. She never smiled.
Her apron was gray and greasy. Her blouse had bits of breakfast all over it, toast crumbs and tea stains and splotches of dried egg yollk. It was her hands, however, that disturbed us most.They were disgusting. They were black with dirt and grime.
And do not forget that it was these hands and fingers that she would plunge into the sweet-jars when we asked for a pennyworth of TreackleToffe or Wine Gums or Nut Clusters, or whatever. There were precious few health laws in those days, and nobody, least of all Mrs. Pratchett , ever thought of using a little shovel for getting sweets out as they do today.
American Inside Out – Teacher’s book.
According to the text, choose the best response.
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United States Coast Guard cadets graduate from the Academy.
Two hundred newly graduated United States Coast Guard Academy students, classified as officers, toss their cadet covers into the air during their graduation ceremony in New London, Conn. on May 23, 2018. Wednesday’s commencement ceremony was the 137th at the academy.
Adapted www.nydailynews.com/news
Based on the text, choose the best alternative.
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Assinale a alternativa em que o coletivo em destaque foi corretamente empregado, considerando o contexto.
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Cuba plane crash: 110 dead as investigators recover flight’black box
The fiery crash of an ageing passenger jet close to Havana’s main airport killed 110 people while three survivors remain gravily in the hospital, making it the Caribean island’s deadliest air disaster in nearly 30 years. The weather was rainy at the airport at the time of the accident and some people could hear a strange noise and saw the plane with an engine on fire. Among the dead are 20 clergy members of an evangelical church, the Mexican pilots and the cabin crew.
Adapted from Independent Online, May 25.
The word “ageing”, in bold in the text, is closest in meaning to
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PRESSURE
Jeremy Berke
Commercial airplane cabins are generally pressurized to an equivalent of 6,000 to 8,000 feet above sea level, in an effort to maintain a healthy oxygen level for both the passengers and the flight crew. When a passenger jet is flying at a cruising altitude of over 36,000 feet, the pressure outside the cabin is_____________ than inside the pressurized cabin. Air pressure has a tendency to equalize, moving from areas of high pressure to low pressure to achieve equilibrium. When a hole rips open on a plane, the suction resulting from the pressure difference between the cabin and the sky could pull nearby people or objects outside. Depending on the size of the hole, such accidents could either create just enough force to shuffle papers around, or, pull a full-size human out of the plane. Survival is unlikely for anyone fully sucked out into the sky.
While in-flight incidents are extremely rare, if you want to survive a crash, research suggests the best place to sit is in a middle seat toward the back of the plane.
http://www.businessinsider.com/
According to the text, we can infer that _______________, EXCEPT,
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Dado um hexágono regular de 6 cm de lado, considere o seu apótema medindo a cm e o raio da circunferência a ele circunscrita medindo R cm. O valor de!$ (R+a \sqrt3) !$ é
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Sabe-se que !$ \begin{pmatrix} { \large 2 \over 3} \end{pmatrix}^x = 4^x !$. Dessa forma, x + 2 é igual a
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