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storchak [24]
3 years ago
10

A heat engine that rejects waste heat to a sink at 520 R has a thermal efficiency of 35 percent and a second- law efficiency of

60 percent. Determine the temperature of the source that supplies heat to this engine.

Engineering
1 answer:
xeze [42]3 years ago
6 0

Answer:

The source temperature is 1248 R.

Explanation:

Second law efficiency of the engine is the ratio of actual efficiency to the maximum possible efficiency that is reversible efficiency.

Given:  

Temperature of the heat sink is 520 R.

Second law efficiency is 60%.

Actual thermal efficiency is 35%.

Calculation:  

Step1

Reversible efficiency is calculated as follows:

\eta_{II}=\frac{\eta_{a}}{\eta_{rev}}

0.6=\frac{0.35}{\eta_{rev}}

\eta_{rev}=0.5834

Step2

Source temperature is calculated as follows:

\eta_{rev}=1-\frac{T_{L}}{T}

\eta_{rev}=1-\frac{520}{T}

0.5834=1-\frac{520}{T}

T = 1248 R.

The heat engine is shown below:

Thus, the source temperature is 1248 R.

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Answer:

a) ≈ 30 mins

b) 8 vpm

Explanation:

<u>a) Determine how long after the first vehicle arrival will the queue dissipate</u>

The time after the arrival of the first vehicle for the queue to dissipate

= 29.9 mins ≈ 30 mins

<u>b) Determine the average service rate at the parking lot gate </u>

U = A / t

where : A = 240 vehicles , t = 30

U = 240 / 30 = 8 Vpm

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3 years ago
A nanometer connected to a pipe indicates a negative gauge pressure of 70mm of mercury .what is the pressure in the pipe in N/m^
prohojiy [21]

Based on the calculations, the absolute pressure in the pipe is equal to 90,670.4‬ N/m².

<h3>How to calculate the absolute pressure?</h3>

Mathematically, absolute pressure can be calculated by using this formula:

P_{abs} = P_{atm} + P_{guage}

<u>Scientific data:</u>

Atmospheric pressure (Patm) = 1 bar = 1 × 10⁵ N/m²

Head (h) = -70mmhg = -0.07 m hg

Acceleration due to gravity = 9.8 m/s²

Density of mercury = 13,600 kg/m³.

Next, we would determine the gauge pressure:

P_{guage} = \rho gh\\\\P_{guage} =  -13600 \times 9.8 \times 0.07\\\\P_{guage} = -9,329.6\;N/m^2

Now, we can calculate the absolute pressure:

P_{abs} = P_{atm} + P_{guage}\\\\P_{abs} = 1 \times 10^5 - 9329.6

Absolute pressure = ‭90,670.4‬ N/m².

Read more on absolute pressure here: brainly.com/question/10013312

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6 0
2 years ago
The "Crawler" developed to transport the Saturn V launch vehicle from the assembly building to the launch pad is the largest lan
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Answer:

a) 152000 slugs

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Explanation:

A body with a weight of 4.9*10^6 lbf has a mass of

4.9*10^6 lbm * 1 lbf/lbm = 4.9*10^6 lbm

This mass value can then be converted to other mass values.

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Therefore:

4.9*10^6 lbm * 1 slug / (32.17 lbm) = 152000 slugs

1 lb is 0.453 kg

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4.9*10^6 lbm / (1/0.453) * kg/lbm = 2220000 kg

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3 years ago
An electron is traveling with initial kinetic energy K in a uniform electric field. The electron comes to rest momentarily after
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Answer:

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The force that does work on the electron is the one due to the electric field E, and by definition of electric field, can be expressed as follows:

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