1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Zina [86]
3 years ago
15

A long homogeneous resistance wire of radius ro = 5 mm is being used to heat the air in a room by the passage of electric curren

t. Heat is generated in the wire uniformly at a rate of g=5'107 W/m as a result of resistance heating. If the temperature of the outer surface of the wire remains at 180°C, determine the temperature at r = 2 mm after steady operation conditions are reached. Take the thermal conductivity of the wire to be k = 8 W/m x °C.
Engineering
1 answer:
VARVARA [1.3K]3 years ago
6 0

Answer:

T = 212.8125°C

Explanation:

Given

radius of the wire, r_{0} = 5 mm 0.005 m

heat generated, g = 5 x 10^{7} W/m^{3}

outer surface temperature, T_{S} = 180°C

Thermal conductivity, k = 8 W / m-k

Now maximum temperature occurs at the center of the wire

that is at r=0,

Therefore, T_{o}=T_{S}+\frac{g\times r_{o}^{2}}{4\times k}

                  T_{o}=180+\frac{5\times 10^{7}\times 0.005^{2}}{4\times 8}

                 T_{o}=219.0625°C

Therefore, temperature at r = 2 mm

\frac{T-T_{S}}{T_{O}-T_{S}}= 1-\left (\frac{r}{r_{O}}  \right )^{2}

\frac{T-180}{219.0625-180}= 1-\left (\frac{2}{5}  \right )^{2}

Therefore, T = 212.8125°C

You might be interested in
Consider the freeway in Problem 1. At one point along this freeway there is a 4% upgrade with a directional hourly traffic volum
ryzh [129]

Answer:

The Question is incomplete, the complete question is as follows:

<em>Consider the freeway in Problem 1. At one point along this freeway there is a 4% upgrade with a directional hourly traffic volume of 5,435 vehicles. If all other conditions are as described in Problem 1, how long can this grade be without the freeway LOS dropping to F? </em>

A six-lane rural freeway (three lanes in each direction) has regular weekday users and currently operates at maximum LOS C conditions. The base free-flow speed is 65 mi/h, lanes are 11 ft wide, the right-side shoulder is 4 ft wide, and the interchange density is 0.25 per mile. The highway is one rolling terrain with 10% large trucks and buses (no recreational vehicles), and the peak-hour factor is 0.90. Determine the hourly volume for these conditions

Explanation:

<em>Make the assumption Base continuous flow velocity (BFFS)= 65 mph. </em>

Pitch width= 11 ft.

Decrease in lane width pace,fLW= 1.9 mph.

Complete Lateral clearance= 4 ft. Lateral clearance speed reduction, fLC= 0.8 mph.

Complete Width of the Ramp= 0.25 mile.

Velocity reduction proportional to the ramp height, f ID= 0 mph.

Assume lane number to be = 3.

Reduction in speed corresponding to no. of lanes, fN = 3 mph

Free Flow Speed (FFS) = BFFS – fLW – fLC – fN – fID = 65 – 1.9 – 0.8 – 3 – 0 = 59.3 mph

Peak Flow, V veh/hr

Peak-hour factor = 0.90

Trucks = 10%

Rolling Terrain

fHV = 1/ (1 + 0.10 (2.5-1)) = 1/1.15 = 0.8696

fP = 1.0

Peak Flow Rate, Vp = V / (PHV*n*fHV*fP) = V/ (0.90*3*0.8696*1.0) = 0.426V veh/hr/ln

Average speed of vehicles, S = FFS = 59.3 mph

Level of service C

Density of LOS C lies between 18 - 25 veh/mi/ln

Maximum density = 25 veh/mi/ln

Density = V​​​​​​p /S = 25

0.426V = 25 * 59.3

V = 3480 veh/hr

b) V = 5435 veh/hr

LOS dropping to F

Max density = 45 veh/mi/ln

Density = Vp/S = 45

V​​​​​​p = 45 * 59.3 = 2668.5 veh/hr/ln

V/(PHF * n * f​​​​​​HV * f​​​​​​P​​​) = 2668.5

f​​​​​​HV = 5435/(0.9*3*2668.5*1.0) = 0.754

1/(1+0.10 (E​​​​​​T -1)) = 0.754

E​​​​​​T = 4.26 ~ 3.5

<em>For 4% upgrade and 10% trucks with E​​​​​​T = 3.5, length of the grade is Greater than 1.0 miles</em>

6 0
3 years ago
Read 2 more answers
7. Sockets internal designs come in what sizes?
MAXImum [283]

Answer:

These drive fittings come in four common sizes: 1⁄4 inch, 3⁄8 inch, 1⁄2 inch, and 3⁄4 inch (referred to as "drives", as in "3⁄8 drive").

3 0
3 years ago
Is an example of an electrical device.
Yuki888 [10]
I think that it is all of the above
5 0
3 years ago
Read 2 more answers
Write a statement that calls the recursive method backwardsAlphabet() with parameter startingLetter.
Tcecarenko [31]

Recursion refers to the act of calling a function itself. With the use of this strategy, complex problems can be reduced to more manageable, simpler ones. Recursion might be a little challenging to comprehend. The best method to figure out how it works is to experiment with it.

<h3>How to write a programme by recursive method ?</h3>

The process of making a function call itself is known as recursion. With the use of this strategy, complex problems can be reduced to more manageable, simpler ones. Recursion might be a little challenging to comprehend. Experimenting with it is the most effective way to learn how it functions.

public class Recursive Calls {

public static void backwards Alphabet(char currLetter) {

if (currLetter == 'a') {

System.out.println(currLetter);

}

else {

System.out.print(currLetter + " ");

backwards Alphabet(--currLetter);

}

return;

}

public static void main (String [] args) {

char starting Letter = '-';

starting Letter = 'z';

// Your solution goes here

backwards Alphabet(starting Letter);

return;

}

}

To learn more about recursive method refer to :

brainly.com/question/24167967

#SPJ4

6 0
1 year ago
9. How is the Air Delivery temperature controlled during A/C operation?
Rzqust [24]

Answer:

i believe the answer is a but i could be wrong

Explanation:

i hope it helps

6 0
3 years ago
Other questions:
  • A 1-lb collar is attached to a spring and slides without friction along a circular rod in a vertical plane. The spring has an un
    6·1 answer
  • Compare automation and autonomous
    12·1 answer
  • Which one of the following statements about the Wright brothers is not true?
    6·1 answer
  • A process involves the removal of oil and other liquid contaminants from metal parts using a heat-treat oven, which has a volume
    10·1 answer
  • An actual vapour compression system comprises following process represents a. 1-2 Compression process b. 2-3 Condens 1 (or heat
    5·1 answer
  • For a very rough pipe wall the friction factor is constant at high Reynolds numbers. For a length L1 the pressure drop over the
    9·1 answer
  • If the power to a condensing unit has been turned off for an extended period of time, the _________________________ should be en
    12·1 answer
  • Which of these is shown in the animation below?
    6·1 answer
  • A coil consists of 200 turns of copper wire and have a cross-sectional area of 0.8 mmm square.The mean length per turn is 80 cm
    13·1 answer
  • Which of the following describes a tropical grassland environment?
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!