Ask question

Ask question

All categories

3 years ago

10

PLEASE HELP! I'm in the middle of a test and the teacher didn't go over the material!

1 answer:

stepan [7]3 years ago

3 0

Answer:

1. 4/d and 1

2. Engineering tech with 3, Engineer with 1, and Scientist with 2

Explanation:

I'm pretty sure but tell me if im wrong

You might be interested in

The wall of drying oven is constructed by sandwiching insulation material of thermal conductivity k = 0.05 W/m°K between thin me

masha68 [24]

Answer:

86 mm

Explanation:

From the attached thermal circuit diagram, equation for i-nodes will be

$\frac {T_ \infty, i-T_{i}}{ R^{"}_{cv, i}} + \frac {T_{o}-T_{i}}{ R^{"}_{cd}} + q_{rad} = 0$ Equation 1

Similarly, the equation for outer node “o” will be

$\frac {T_{ i}-T_{o}}{ R^{"}_{cd}} + \frac {T_{\infty, o} -T_{o}}{ R^{"}_{cv, o}} = 0$ Equation 2

The conventive thermal resistance in i-node will be

$R^{"}_{cv, i}= \frac {1}{h_{i}}= \frac {1}{30}= 0.033 m^{2}K/w$ Equation 3

The conventive hermal resistance per unit area is

$R^{"}_{cv, o}= \frac {1}{h_{o}}= \frac {1}{10}= 0.100 m^{2}K/w$ Equation 4

The conductive thermal resistance per unit area is

$R^{"}_{cd}= \frac {L}{K}= \frac {L}{0.05} m^{2}K/w$ Equation 5

Since $q_{rad}$ is given as 100, $T_{o}$ is 40 $T_ \infty$ is 300 $T_{\infty, o}$ is 25

Substituting the values in equations 3,4 and 5 into equations 1 and 2 we obtain

$\frac {300-T_{i}}{0.033} +\frac {40-T_{i}}{L/0.05} +100=0$ Equation 6

$\frac {T_{ i}-40}{L/0.05}+ \frac {25-40}{0.100}=0$

$T_{i}-40= \frac {L}{0.05}*150$

$T_{i}-40=3000L$

$T_{i}=3000L+40$ Equation 7

From equation 6 we can substitute wherever there’s $T_{i}$ with 3000L+40 as seen in equation 7 hence we obtain

$\frac {300- (3000L+40)}{0.033} + \frac {40- (3000L+40)}{L/0.05}+100=0$

The above can be simplified to be

$\frac {260-3000L}{0.033}+ \frac {(-3000L)}{L/0.05}+100=0$

$\frac {260-3000L}{0.033}=50$

-3000L=1.665-260

$L= \frac {-258.33}{-3000}=0.086*10^{-3}m= 86mm$

Therefore, insulation thickness is 86mm

8 0

3 years ago

Which of the following is a valid reason why a scientist might reject a scientific theory

Flauer [41]

C I think hope it helps :)

6 0

3 years ago

Read 2 more answers

Poached eggs are cooked in bath of boiling water at 100°C. Over time they reach thermal equilibrium with the bath. They are then

barxatty [35]

Answer:

Check the explanation

Explanation:

Kindly check the attached images below to see the step by step explanation to the question above and also note that I derived the whole expressions in variable firm that are required to solve this question and giving reasons for each step so that you can employ these steps in solving new problems.

8 0

3 years ago

Mary wants to design a physical object and is on the step of material selection. Which charts will help her for material selecti

strojnjashka [21]

D Ashby chart is probably the answer

3 0

3 years ago

Read 2 more answers

Vapor lock occurs when the gasoline is cooled and forms a gel, preventing fuel flow and

Sergeu [11.5K]

Answer:

True

Explanation:

4 0

3 years ago

Read 2 more answers