An air-standard dual cycle has a compression ratio of 9. at the beginning of compression, p, 100 kpa, t, 300 k, and v 14 l. the heat addition is 22.7 kj, with one half added at constant volume and one half added at constant pressure. determine (a) the temperatures at the end of each heat addition process, in k. (b) the net work of the cycle per unit mass of air, in kj/kg. (c) the thermal efficiency. (d) the mean effective pressure, in kpa

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

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myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.