Questões - IME 2010 | Gabarito e resoluções

(IME - 2010/2011 - 1 FASE) Scientists say juggling e-mail, phone calls and other incoming information can change how people think and behave. They say our ability to focus is being undermined by bursts of information. These play to a primitive impulse to respond to immediate opportunities and threats. The stimulation provokes excitement a dopamine squirt that researchers say can be addictive. In its absence, people feel bored. The resulting distractions can have deadly consequences, as when cell phone-wielding drivers and train engineers cause wrecks. And for millions of people these urges can inflict nicks and cuts on creativity and deep thought, interrupting work and family life. What does the passage imply?

[IME- 2010/2011 - 1a fase] A figura acima apresenta um circuito composto por dois solenoides com resistncias desprezveis e dois resistores de 2 Ω ligados a uma bateria. Uma corrente induzida em uma espira situada entre os dois solenoides quando esta se desloca da direita para a esquerda, a partir da posio equidistante em relao aos solenoides. Sabendo-se que as influncias mtuas dos campos magnticos no interior de cada solenoide so desprezveis, pode-se afirmar que o valor da tenso da bateria em volts e o sentido da corrente induzida na espira para o observador so: Dados: Campo magntico no interior de cada solenoide: Permeabilidade magntica no vcuo: Nmero de espiras de cada solenoide: 10 Comprimento de cada solenoide: 4 cm

[IME- 2010/2011 - 1a fase] Considere um meio estratificado em N camadas com ndices de refrao , como mostrado na figura acima, onde esto destacados os raios traados por uma onda luminosa que os atravessa, assim como seus respectivos ngulos com as normais a cada interface. Se para , ento N igual a: Observaes: A escala da figura no est associada aos dados. Admite-se que sempre ocorrer a refrao.

(IME - 2010/2011 - 1 FASE) The history of technology is full of breakthroughs in one field that wound up working wonders in a related one. The 300B vacuum tube, introduced by Western Electric in 1937 to amplify telephone signals, found a far more enduring use as a high-fidelity audio amplifier. The atomic clocks first used in the 1960s by the U.S. military to track Sputnik and later to validate Albert Einsteins relativity theories are now the basis of Global Positioning System. And of course, the magnetron, invented in the 1920s at General Electric and used in radars during World War II, later found itself repurposed as the basis for the microwave oven. According to the text, what is correct to say?

[IME- 2010/2011 - 1a fase] A figura acima apresenta uma fonte sonora pontual que emite uma onda harmnica esfrica em um meio no dispersivo. Sabendo que a mdia temporal da intensidade da onda diretamente proporcional ao quadrado da sua amplitude, pode-se afirmar que a amplitude a uma distncia r da fonte proporcional a:

(IME - 2010/2011 - 1 FASE) The history of technology is full of breakthroughs in one field that wound up working wonders in a related one. The 300B vacuum tube, introduced by Western Electric in 1937 to amplify telephone signals, found a far more enduring use as a high-fidelity audio amplifier. The atomic clocks first used in the 1960s by the U.S. military to track Sputnik and later to validate Albert Einsteins relativity theories are now the basis of Global Positioning System. And of course, the magnetron, invented in the 1920s at General Electric and used in radars during World War II, later found itself repurposed as the basis for the microwave oven. According to the text, complete the sentence: The microwave oven

[IME- 2010/2011 - 1a fase] Uma fina placa metlica , apoiada em um tablete de cortia no fundo de um frasco cilndrico, dista 5 metros de uma placa idntica , fixa no teto, conforme a figura acima. As duas placas formam um capacitor carregado com Q coulombs. Enche-se o referido frasco com um lquido de ndice de refrao n = 2,5, at a altura de h metros. Em seguida, lana-se sobre o centro da superfcie um raio de luz monocromtica, sob um ngulo de 30 com a vertical. Sabendo que a energia armazenada no capacitor fica reduzida a 0,6 do valor inicial, que o raio refratado atinge um ponto situado a x metros do centro do fundo do frasco e desprezando o efeito de borda do capacitor, podemos dizer que o valor aproximado de x : Observao: A espessura da cortia desprezvel em relao altura h.

[IME- 2010/2011 - 1a fase] Uma pedra est presa a um fio e oscila da maneira mostrada na figura acima. Chamando T a trao no fio e o ngulo entre o fio e a vertical, considere as seguintes afirmativas: I) O mdulo da fora resultante que atua na pedra igual a T sen. II) O mdulo da componente, na direo do movimento, da fora resultante que atua na pedra mximo quando a pedra atinge a altura mxima. III) A componente, na direo do fio, da fora resultante que atua na pedra nula no ponto em que a pedra atinge a altura mxima. Est(o) correta(s) a(s) afirmativa(s):

(IME - 2010/2011 - 1 FASE) Soon enough, say some engineers, miniature wireless sensors will be located in spots where it would be inconvenient, to say the least, to change their batteries inside your body, within the steel and concrete of buildings, in the dangerous innards of chemical plants. But today, even the most robust nodes can be counted on to last only a few years. Ideally, engineers need wireless sensors that can last forever without external power sources or battery changes. According to research presented in December at the International Electron Devices Meeting, in Baltimore, that dream is within reach. What inconvenience is mentioned in the text?

(IME -2010/2011 - 1 FASE) Soon enough, say some engineers, miniature wireless sensors will be located in spots where it would be inconvenient, to say the least, to change their batteries inside your body, within the steel and concrete of buildings, in the dangerous innards of chemical plants. But today, even the most robust nodes can be counted on to last only a few years. Ideally, engineers need wireless sensors that can last forever without external power sources or battery changes. According to research presented in December at the International Electron Devices Meeting, in Baltimore, that dream is within reach. What does the sentence According to research presented in December at the International Electron Devices Meeting, in Baltimore, that dream is within reach. imply about the text?

[IME- 2010/2011 - 1a fase] A figura acima representa o sistema de bombeamento de gua de uma residncia. As alturas de suco () e recalque () valem, respectivamente, 10 e 15 m. O sistema projetado para trabalhar com uma vazo de . A bomba que efetua o recalque da gua acionada por um motor eltrico, de corrente contnua, que alimentado por uma tenso de 200 V. A corrente de operao do motor, em ampres, para que o sistema opere com a vazo projetada , aproximadamente: Observao: as perdas internas do motor eltrico e da bomba so desprezveis. Dados: as perdas devido ao acoplamento entre o motor e a bomba so de 30%; acelerao da gravidade: massa especfica da gua: 1 kg/L

[IME- 2010/2011 - 1a fase] Um sistema composto por dois geradores denominados e , cuja tenso de sada , apresentado na figura acima. Este sistema alimenta uma carga que opera com uma tenso V e demanda da rede uma corrente I. O valor de em funo de , de modo que o gerador atenda 40% da potncia da carga, :

(IME - 2010/2011 - 1 FASE) Soon enough, say some engineers, miniature wireless sensors will be located in spots where it would be inconvenient, to say the least, to change their batteries inside your body, within the steel and concrete of buildings, in the dangerous innards of chemical plants. But today, even the most robust nodes can be counted on to last only a few years. Ideally, engineers need wireless sensors that can last forever without external power sources or battery changes. According to research presented in December at the International Electron Devices Meeting, in Baltimore, that dream is within reach. The expression to say the least in the text suggests that

(IME - 2010/2011 - 1 FASE) Recently, I was looking for something online, or probably browsing aimlessly, when I happened on a name I hadnt thought of since I was a child: Alfred P. Morgan. Someone had uploaded a digitized version of The Boy Electrician. I was instantly swept back more than half a century to my local library. In my mind I saw the familiar metal shelving and the blue-gray binding of my favorite book, also written and illustrated by Morgan: The Boys First Book of Radio and Electronics. What is known about Alfred P. Morgan?

[IME- 2010/2011 - 1a fase] A gua que alimenta um reservatrio, inicialmente vazio, escoa por uma tubulao de 2 m de comprimento e seo reta circular. Percebe-se que uma escala no reservatrio registra um volume de 36 L aps 30 min de operao. Nota-se tambm que a temperatura na entrada da tubulao 25 C e a temperatura na sada 57 C. A gua aquecida por um dispositivo que fornece 16,8 kW para cada metro quadrado da superfcie do tubo. Dessa forma, o dimetro da tubulao, em mm, e a velocidade da gua no interior do tubo, em cm/s, valem, respectivamente: Dados: /4 = 0,8; massa especfica da gua: 1 kg/L; calor especfico da gua: 4200 J/ kgC