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3 years ago

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Air at 20°c (1 atm) enters into a 5-mm-diameter and 10-cm long circular tube at an average velocity of 5.4 m/s. the tube wall is

maintained at a constant surface temperature of 160°c. determine the convection heat transfer coefficient and the outlet mean temperature. evaluate the air properties at 50°c. the properties of air at 50°c are: ρ = 1.092 kg/m3 μ = 1.963*10-5 kg/m∙s k = 0.02735 w/m∙k cp = 1007 j/kg∙k v = 1.798 *10−5 m2/s μs = 2.420*10−5 kg/m∙s pr = 0.7228

1 answer:

velikii [3]3 years ago

8 0

Im really sorry. pls dont report this comment. i need points. I have a question but I am bad at english and I cant answer peoples

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Answer:

a) See attached picture, b) We know the initial velocity = 0, initial position=0, time=12.0s, acceleration= $2.40m/s^{2}$ , c) the car travels 172.8m in those 12 seconds, d) The car's final velocity is 28.8m/s

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a) In order to draw a sketch of the situation, I must include the data I know, the data I would like to know and a drawing of the car including the direction of the movement and its acceleration, just like in the attached picture.

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c)

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in order to choose the appropriate equation, I must take the knowns and the unknown and look for a formula I can use to solve for the unknown. I know the initial velocity, initial position, time, acceleration and I want to find out the displacement. The formula that contains all this data is the following:

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after cancelling the pertinent units, I get that my answer will be given in meters. So I get:

$x=\frac{1}{2} (2.40\frac{m}{s^{2}} )(12s)^{2}$

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I need to find the final velocity, so I need to use an equation that will use some or all of the known data and the unknown. In order to solve this problem, I can use the following equation:

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Next, since I need to find the final velocity, I can solve the equation just for that, I can start by multiplying both sides by t so I get:

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