4. Consideremos um plano inclinado, onde o corpo de massa m, = 5Kg está ligado a um corpo de massa m= 8Kg pendurado por um fio inextensível que passa através de uma roldana fixa de peso
desprezível. Sabendo que o coeficiente de atrito entre o plano e o corpo é 0,3 e o ângulo do plano é
30º. Considera g = 10m/s?, calcula:
a) A aceleração do sistema
b) A tensão no fio.
(R:38,24N)
Si
30°

Arotating space station is said to create “artificial gravity”—a loosely-defined term used for an acceleration that would be crudely similar to gravity. the outer wall of the rotating space station would become a floor for the astronauts, and centripetal acceleration supplied by the floor would allow astronauts to exercise and maintain muscle and bone strength more naturally than in non-rotating space environments. if the space station is 200 m in diameter, what angular velocity would produce an “artificial gravity” of 9.80 m/s^{2} 2 at the rim?

Two polarizers are oriented at 40∘ to each other and plane-polarized light is incident on them. if only 16 percent of the light gets through both of them, what was the initial polarization direction of the incident light?

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.