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Nesterboy [21]
1 year ago
10

By the end of the day, a 45 ft x 25 ft x 8 ft office has a carbon dioxide air level of 1,100 ppm. Determine the time in hours ne

cessary to reduce this concentration to ambient levels (approximately 325 ppm) assuming 20% of the return is "fresh" makeup air and there are two air changes per hour.
Engineering
1 answer:
Julli [10]1 year ago
6 0

The total hours that are necessary to reduce carbon dioxide level to at least 325 ppm are 4 hours.

<h3>How does carbon dioxide concentration change over time?</h3>

First hour:

  • 1,100 - 20 %
  • 1,100 - 220 = 880

  • 880 - 20%
  • 880 - 176 = 704

Second hour:

  • 704 - 20%
  • 704 - 140.8 =663.2

  • 663.2 - 20%
  • 663.2 - 132.64 = 530.56

Third hour:

  • 530.56 - 20%
  • 530.56 - 106.112 = 424.44

  • 424.44 - 20%
  • 424.44 - 84.88 = 339.55

Fourth hour:

  • 339.55 - 20%
  • 339.55 - 67.91 = 271.64

Learn more about carbon dioxide in: brainly.com/question/3049557

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ludmilkaskok [199]

Answer:

B

Explanation:

This is a two sample t-test and not a matched pair t-test

null hypothesis(H0) will be that mean energy consumed by copper rotor motors is greater than or equal to mean energy consumed by aluminium rotor motors

alternate hypothesis(H1) will be that mean energy consumed by copper rotor motors is less than or equal to mean energy consumed by aluminium rotor motors.

So, option D is rejected

The hypothesis will not compare mean of differences of values of energy consumed by copper rotor motor and aluminium rotor motor.

Option A and C are also rejected

5 0
3 years ago
Why is the back-work ratio much higher in the brayton cycle than in the rankine cycle?
zloy xaker [14]

The back-work ratio much higher in the Brayton cycle than in the Rankine cycle because a gas cycle is the Brayton cycle, while a steam cycle is the Rankine cycle. Particularly, the creation of water droplets will be a constraint on the steam turbine's efficiency. Since gas has a bigger specific volume than steam, the compressor will have to work harder while using gas.

<h3>What are modern Brayton engines?</h3>

Even originally Brayton exclusively produced piston engines, modern Brayton engines are virtually invariably of the turbine variety. Brayton engines are also gas turbines.

<h3>What is the ranking cycle?</h3>

A gas cycle is the Brayton cycle, while the Ranking cycle is a steam cycle. The production of water droplets will especially decrease the steam turbine's performance. Gas-powered compressors will have to do more work since gas's specific volume is greater than steam's.

Th

To know more about Rankine cycle, visit: brainly.com/question/13040242

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4 0
1 year ago
Question 4 (1 point) Sophia is working in her garden. She made two trips with her wagon along the same path to haul supplies. Th
yaroslaw [1]

Answer:

Option A

Explanation:

Please find the attachment

4 0
3 years ago
If he wants to keep the height the same, what could the other dimensions be for him to get the volume he wants?
Fiesta28 [93]

tbm queria saber essa pergunta

8 0
3 years ago
Sandwich materials typically use a high density core with non-structural cover plates. a)True b)- False
Lorico [155]

Answer: False

Explanation: Sandwich materials are usually in composite material form which has a fabrication of two thin layers which are stiff in nature and have  light weighing and thick core .The construction is based on the ratio that is of stiffness to the weight .Therefore, the density of the material in the core is not high and are only connected with the skin layer through adhesive .So the given statement is false that sandwich materials typically use a high density core with non- structural cover plates.

4 0
2 years ago
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