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3 years ago

Which of the following is true defines 'Balance Point'?

Engineering

1 answer:

ICE Princess25 [194]3 years ago

6 0

Answer:

D.) The home heating requirement equals the heat pump output

Explanation:

The definition of a balance point is when a place's heat output equals the heat input

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.a. What size vessel holds 2 kg water at 80°C such that 70% is vapor? What are the pressure and internal energy? b. A 1.6 m3 ves

vesna_86 [32]

Answer:

Part a: The volume of vessel is 4.7680 $m^3$ and total internal energy is 3680 kJ.

Part b: The quality of the mixture is 90.3% or 0.903, temperature is 120 °C and total internal energy is 4660 kJ.

Explanation:

Part a:

As per given data

m=2 kg

T=80 °C =80+273=353 K

Dryness=70% vapour =0.7

<em>From the steam tables at 80 °C</em>

Specific volume of saturated vapours=v_g=3.40527 $m^3/kg$

Specific volume of saturated liquid=v_f=0.00102 $m^3/kg$

Now the relation of total specific volume for a specific dryness value is given as

$v=v_f+x(v_g-v_f)$

Substituting the values give

$v=v_f+x(v_g-v_f)\\v=0.00102+0.7(3.40527-0.00102)\\v_f=2.38399 m^3/kg$

Now the volume of vessel is given as

$v=\frac{V}{m}\\V=v \times m\\V=2.38399 \times 2\\V=4.7680 m^3$

So the volume of vessel is 4.7680 $m^3$ .

Similarly for T=80 and dryness ratio of 0.7 from the table of steam

Pressure=P=47.4 kPa

Specific internal energy is given as u=1840 kJ/kg

So the total internal energy is given as

$u=\frac{U}{m}\\U=u \times m\\U=1840 \times 2\\U=3680 kJ$

The total internal energy is 3680 kJ.

So the volume of vessel is 4.7680 $m^3$ and total internal energy is 3680 kJ.

Part b

Volume of vessel is given as 1.6

mass is given as 2 kg

Pressure is given as 0.2 MPa or 200 kPa

Now the specific volume is given as

$v=\frac{V}{m}\\v=\frac{1.6}{2}\\v=0.8 m^3/kg$

So from steam tables for Pressure=200 kPa and specific volume as 0.8 gives

Temperature=T=120 °C

Quality=x=0.903 ≈ 90.3%

Specific internal energy =u=2330 kJ/kg

The total internal energy is given as

$u=\frac{U}{m}\\U=u \times m\\U=2330 \times 2\\U=4660 kJ$

So the quality of the mixture is 90.3% or 0.903, temperature is 120 °C and total internal energy is 4660 kJ.

5 0

2 years ago

The three resistors in the circuit shown have values of 4ohms 4ohms and 2ohms. The battery has a value of 12 volts. What is the

gtnhenbr [62]

Answer:

2ohms

Explanation:

3 0

3 years ago

Briefly explain how a jet moves

sergejj [24]

Answer:

Jet engines move the airplane forward with a great force that is produced by a tremendous thrust and causes the plane to fly very fast. All jet engines, which are also called gas turbines, work on the same principle. The engine sucks air in at the front with a fan. ... Spinning the turbine causes the compressor to spin.

Explanation:

8 0

2 years ago

A 4KJ of energy is supplied to a machine used for lifting a mass. The force required is 800N. If the machine has an efficiency o

navik [9.2K]

The height at which the mass will be lifted is; 3 meters

<h3>How to utilize efficiency of a machine?</h3>

Formula for efficiency is;

η = useful output energy/input energy

We are given

η = 60% = 0.6

Input energy = 4 KJ = 4000 J

Thus;

0.6 = useful output energy/4000

useful output energy = 0.6 * 4000

useful output energy = 2400 J

Work done in lifting mass(useful output energy) = force * distance moved

Useful output energy = 800 * h

where h is height to lift mass

Thus;

800h = 2400

h = 2400/800

h = 3 meters

Read more about Machine Efficiency at; brainly.com/question/3617034

#SPJ1

8 0

1 year ago

(1.24) Consumer Reports is doing an article comparing refrigerators in their next issue. Some of the characteristics to be inclu

kondaur [170]

Answer:

“height is a quantitative variable ”

Explanation:

According to the question asked, answer is “height is a quantitative variable ”

Height is a quantitative variable because it is related to the measurement and in measurement, when we measure something we deal with number (numerical data)

Numerical data is a type of quantitative data that is why we say “height is a quantitative variable”

There are some other possible questions in the given paragraph which I would like to mention here, are as following:

Which are the categorical variables in the given report?

<u>Answer: </u>Energy star complaints

Top, Bottom or side-by-side freezer

Which are the quantitative variables in the given report?

<u>Answer:</u> Estimated Energy Consumption in kilowatts

Width, depth, and height in inches

Capacity in Cubic Feet

What are the individuals in the report?

<u>Answer: </u>The brand name and model

8 0

2 years ago