Xilanh 3 tầng cho như hình trên dùng để lật mui xe tải, khi đầy tải thì xilanh chịu lực tương đương 4000 kg tại mọi vị trí trên hành trình. Bán kính các tầng giảm dần: 100 mm, 80 mm, 60 mm. Lưu lượng bơm là 10 l/min, tính toán tốc độ tiến và áp suất yêu cầu cho mỗi tầng của xilanh.

The summit of chimborazo, in ecuador, which is at a distance of about 6,384 km from the earth’s center. the bottom of the mariana trench, in the western pacific ocean, which is nearly 6,370 km from the center of the earth. on the surface of earth on the equator line.

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

The number of passengers who arrive at the platform of a subway station for the 10 am train is a random variable with a mean of 120 and a variance of 16. find the lower bound of the probability that there will be between 100 and 140 passengers (round off to second decimal place).