O Negacionismo Científico vem causando diversos prejuízos ao desenvolvimento de nações, bem como a seu ecossistema e à sua população. Os negacionistas científicos provocaram uma série de ações, como nos EUA e no Canadá, para disseminar dúvidas sobre questões que já tinham sido comprovadas pela Ciência nos EUA. Quais os dois fatos recentemente questionados por esses “mercadores da dúvida”? A) A chegada do homem na Lua e a conquista do espaço. B) Aquecimento global e os malefícios do cigarro. C) Os benefícios da vacina contra a varíola e a febre amarela. D) O consumo do excesso de açúcares e gorduras como causa da cárie nos dentes. E) A existência de água e seres extraterrestres na Lua.

Aquick transition of the operating speed of a shaft from its critical speed will whirl amplitude. (a) increase (b) limit (c) not affect (d) zero

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?

Apiston-cylinder device contains 0.1 m3 of liquid water and 0.9 m3 of water vapor in equilibrium at 800 kpa. heat is transferred at constant pressure until the temperature of water reaches 350 °c. determine (a) the quality of water at the initial state (b) the work associated with this process, (c) the heat associated with this process.