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sladkih [1.3K]
3 years ago
12

A heat recovery system​ (HRS) is used to conserve heat from the surroundings and supply it to the Mars Rover. The HRS fluid loop

s use Freon as the working fluid. The instrumentation must be kept as a temperature greater than −67 degrees Fahrenheit​ [°F] to avoid damage.
The temperature in the area of Mars where the rover is exploring is 189 kelvins​ [K]. If the system must remove 47.4
British Thermal Units​ [BTU] of​ energy, what volume of Freon is needed in units of liters​ [L]?

Some facts about​ Freon:
The specific heat of Freon is 74
joules per mole kelvin J/(mol °K)]
The specific gravity of Freon is 1.49
The molecular mass of Freon is 120 grams per mole​ [g/mol]
Engineering
1 answer:
blagie [28]3 years ago
7 0

Answer:

0.304 L of Freon is needed

Explanation:

Q = mCT

Q is quantity of energy that must be removed = 47 BTU = 47×1055.06 = 49587.82 J

C is specific heat of Freon = 74 J/mol.K = 74 J/mol.K × 1 mol/120 g = 0.617 J/g.K

T is temperature in the area of Mars = 189 K

m = Q/CT = 49587.82/(0.617×189) = 452.23 g = 452.24/1000 = 0.45223 kg

Density of Freon = specific gravity of Freon × density of water = 1.49 × 1000 kg/m^3 = 1490 kg/m^3

Volume of Freon = mass/density = 0.45223/1490 = 0.000304 m^3 = 0.000304×1000 = 0.304 L

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python Given num_rows and num_cols, print a list of all seats in a theater. Rows are numbered, columns lettered, as in 1A or 3E.
MissTica

Explanation:

First of all get the input from the user, number of rows and number of columns where rows represents seat digit number and column represents the seat letter

rows is initialized to 1 to ensure that row starts at 1 or you can remove it then seat number will start from 0.

The first loop is used for digits starting from 1 to number of rows

The second loop is used for letters starting from 1 to number of columns

since rows and cols are not of the same type that's why we are converting the int type to string type

print(str(rows)+cols) counter will keep updating the columns A, B, C.....

rows= rows + 1 counter will keep updating the rows 1, 2, 3....

Code:

Please refer to the attached image.

Output:

Please enter the number of rows: 2

Please enter the number of columns: 3

1A

1B

1C

2A

2B

2C

3 0
3 years ago
A hypothetical A-B alloy of composition 57 wt% B-43 wt% A at some temperature is found to consist of mass fractions of 0.5 for b
Dennis_Churaev [7]

Answer:

composition of alpha phase is 27% B

Explanation:

given data

mass fractions  = 0.5 for both

composition = 57 wt% B-43 wt% A

composition = 87 wt% B-13 wt% A

solution

as by total composition Co = 57 and by beta phase composition  Cβ = 87  

we use here lever rule that is

Wα = Wβ   ...............1

Wα = Wβ = 0.5

now we take here left side of equation

we will get

\frac{C_\beta - Co}{C_\beta - Ca}   = 0.5

\frac{87 - 57}{87 - Ca} = 0.5  

solve it we get

Ca = 27

so composition of alpha phase is 27% B

8 0
4 years ago
Which of the following is NOT true about hydraulic systems?
Dmitry [639]

Answer: The answer is D

D.In hydraulic systems, the operating temperatures must be kept between 170�F and 180°F 

Explanation:

The operating temperature for hydraulic systems is 140°F and below. Anything above this temperature is too high and will reduce the useful life of hydraulic fluid.

Most often problems associated with hydraulic systems are caused by fluid contaminated with particulate matter.

7 0
3 years ago
Can someone pls give me the answer to this?
Zolol [24]
During World War ll, the United States and the Soviet Union fought together as the allies against the Axis power. However, the relationship between the two nations was a tense one. Americans had long been wary of Soviet communism and concerned about Russian leader Joseph Stalin’s tyrannical rule of his own country
7 0
3 years ago
Suppose that you and two classmates are discussing the design of a roller coaster. One classmate says that each summit must be l
Kitty [74]

Answer:

The second classmate is right.

Explanation:

The height of first summit provides the potential energy it will use to climb the following ones.

Ep = m * g * h

Where

m: mass

g: acceleration of gravity

h: height

When the train goes downwards the potential energy is converted into kinetic energy (manifested as speed) and when it climbs it consumes its kinetical energy. As long as no summit is taller than the first the train should have enough energy to climb them.

Also it must be noted that friction also consumes energy, and if the track is too lomg all the energy might be consumed by it.

8 0
3 years ago
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