A long, uninsulated steam line with a diameter of 89 mm and a surface emissivity of 0.8 transports steam at 200C and is exposed to atmospheric air and large surroundings at an equivalent temperature of 20C. (a) Calculate the heat loss per unit length for a calm day. (b) Calculate the heat loss on a breezy day when the wind speed is 8 m/s. (c) For the conditions of part (a), calculate the heat loss with a 20-mm-thick layer of insulation (k 0.08 W/m K). Would the heat loss change significantly with an appreciable wind speed

Answers

Answer 1

Answer:

[tex]Q_net=534.67\frac{w}{m}[/tex]

Explanation:

From the question we are told that:

Steam line diameter [tex]D=89mm \approx 0.089m[/tex]

Surface emissivity [tex]\mu=0.8[/tex]

Steam temp [tex]T_s=200\textdegree C \approx 200+273=473k[/tex]

Surrounding temp [tex]T_a=20 \textdegree C \aprrox 20+273= 293k[/tex]

 

Generally the equation for heat loss per unit length due to radiation [tex]Q_{net}[/tex] is mathematically given by

[tex]Q_net=\sigma*\mu>(\pi *d)*(T_s^4-T_a^4)[/tex]

[tex]Q_net=5.6*10^8*0.8*(\pi *0.089)*(473^4-293^4)[/tex]

[tex]Q_net=534.67\frac{w}{m}[/tex]


Related Questions

In the process of changing a flat tire, a motorist uses a hydraulic jack. She begins by applying a force of 58 N to the input piston, which has a radius r1. As a result, the output plunger, which has a radius r2, applies a force to the car. The ratio r2/r1 has a value of 8.2. Ignore the height difference between the input piston and output plunger and determine the force that the output plunger applies to the car.

Answers

Answer:

The correct answer is "3899.92 N".

Explanation:

The given values are:

Force,

[tex]F_{app}=58 N[/tex]

Ratio,

[tex]\frac{R_2}{R_1}=8.2[/tex]

As we know,

Area, [tex]A=\pi r^2[/tex]

or,

⇒  [tex]\frac{F_2}{F_1} =\frac{A_2}{A_1}[/tex]

On substituting the value of "A", we get

⇒  [tex]\frac{F_2}{F_1} =\frac{\pi r_2^2}{\pi r_1^2}[/tex]

⇒  [tex]\frac{F_2}{F_1} =\frac{r_2^2}{r_1^2}[/tex]

On applying cross-multiplication, we get

⇒  [tex]F_2=F_1\times (\frac{r_2}{r_1} )^2[/tex]

On substituting the given values, we get

⇒       [tex]=58\times (8.2)^2[/tex]

⇒       [tex]=58\times 67.2[/tex]

⇒       [tex]=3899.92 \ N[/tex]

Please help 23 also 29 the answer choices are reflection or refraction your fraction absorption

Answers

Answer:

23. Option B. Hertz

29. Refraction.

Explanation:

23. Determination of the unit of measurement of frequency.

Frequency is simply defined as the number of oscillation made in one second. Mathematically, frequency can be represented as:

Frequency = 1/period

f = 1/T

Period is measured in seconds.

Thus, the unit of frequency becomes

f = 1/T

f = 1/s = s¯¹ (Hertz)

Therefore, the unit of frequency is Hertz.

29. When a wave enters a new medium, the speed of the wave is uttered. This leads to the bending of the wave. When this occurs, we can say refraction has taken place.

The speed of a wave is 40 m/s. If the wavelength is 80 centimeters, what is the frequency of the wave?

SOLVE IT COMPLETELY

Answers

Question:-

The speed of a wave is 40 m/s. If the wavelength is 80 centimeters, what is the frequency of the wave ?

Answer:-

Given:-

Velocity (V) = 40 m/s

Wavelength [tex] (\lambda) [/tex] = 80 cm = 0.8 m

To Find:-

The frequency (F) of the wave.

Solution:-

We know,

[tex] \bf V \: = \: F \: × \: \lambda [/tex]

40 = F × 0.8

F = [tex] \frac{40}{0.8} [/tex]

F = 50

The frequency of the wave is 50 Hz. [Answer]

Which object orbits object E?
A
B
C
Or D

Answers

Answer:

its D I hope this helps you

A 100-n object and a 50-n object are placed on scales a and b respectively inside an elevator ascending with constant velocity 3.0m/s which statement below correctly describes the readings on the scales inside the elevator

Answers

Answer: b

Explanation:

The reading of the scale of the elevator  ascending with constant velocity is 150 N.

Reading of the scale

The reading of the scale on the elevaor is calculated by applying Newton's second law of motion;

R = m(a + g)

R = ma + mg

R = F + W

where;

a is the acceleration of the objects

At constant velocity, the acceleration of the object is zero (0).

R = 0 + 100 + 50

R = 150 N

Thus, the reading of the scale of the elevator  ascending with constant velocity is 150 N.

Learn more about reading of scale here: https://brainly.com/question/2516315

19
What is the mass of a ball that is traveling 30 m/s and has 4.5 J of kinetic energy?
ave a GPF of 35512

Answers

Answer: The mass of ball is 10 grams.

Explanation:

Given : Kinetic energy = 4.5 J

Velocity = 30 m/s

The formula for Kinetic energy is as follows.

[tex]K.E = \frac{1}{2}mv^{2}[/tex]

where,

K.E = Kinetic energy

m = mass

v = velocity

Substitute the values into above formula as follows.

[tex]K.E = \frac{1}{2}mv^{2}\\4.5 J = \frac{1}{2} \times m \times (30 m/s)^{2}\\m = \frac{4.5 J \times 2}{900 m^2/s^2} (1 Js^{2} = kg m^{2})\\= 0.01 kg (1 kg = 1000 g)\\= 10 g[/tex]

Thus, we can conclude that the mass of ball is 10 grams.

The energy of motion is called...?

Answers

The answer is Kinetic energy

A chain is wrapped around pulley and pulled with a force of
16.0N .The pulley has a radius of 0.20 m. The pulley's rotational
speed increases from 0.0 to 17.0 rev/min in 5.00s What is the moment
of inertia of Pulley?

Answers

The moment of inertia of Pulley is 8.89 kgm².

Angular acceleration of the pulley

The angular acceleration of the pulley is calculated as follows;

[tex]\alpha = \frac{\omega_f - \omega _i}{t}[/tex]

where;

ωi is the initial angular velocity = 0 ωf is the final angular velocity = 17 rev/mint is the time of motion

Final angular velocity in radian per second is calculated as

[tex]\omega _f = 17 \frac{rev}{\min} \times \frac{2\pi \ rad}{1 \ rev} \times \frac{1\min}{60 \ s} = 1.78 \ rad/s[/tex]

Now, solve for angular acceleration

[tex]\alpha = \frac{1.78-0}{5} \\\\\alpha = 0.36 \ rad/s^2[/tex]

Moment of inertia of the pulley

The the moment of inertia of Pulley is determined using the formula for torque.

Iα = Fr

I = Fr/α

I = (16 x 0.2)/(0.36)

I = 8.89 kgm²

Thus, the moment of inertia of Pulley is 8.89 kgm².

Learn more about moment of inertia here: https://brainly.com/question/25803184

A uniform metre rule of mass 100g balance the 40cm mark when a mass x is placed at the 20cm mark
what is the value of x​

Answers

Answer:

X = 50 g

Explanation:

Please see attached photo for explanation.

From the attached photo,

Anticlock–wise moment = X × 20

Clockwise moment = 100 × 10

Anticlock–wise moment = clockwise moment

X × 20 = 100 × 10

X × 20 = 1000

Divide both side by 20

X = 1000 / 20

X = 50 g

Therefore, the value of X is 50 g

The light waves transfer their oscillations and energy to other object in what way?

The frequency of the light waves physically causes the object to move
The energy of the light wave transfers to the electrons of the material which causes them to gain that energy
The wavelength of the light changes the velocity of the atoms in the material
The amplitude of the light will affect how much of it shines on the object

Answers

Answer: b the energy of light...

Explanation:

The Earth Science students are making a human scale model of the solar system out on the school playground. The school itself represents the Sun. In the model 1 AU = 100 meters (the length of a football field). How far from the school will the student representing Mars stand? A) 50 meters B) 105 meters 150 meters D) 1500 meters NEED HELP ASAP​

Answers

In the model 1 AU = 100 meters (the length of a football field) , then mars would be 150 meters far from the school, therefore the correct answer is option C.

What is a unit of measurement?

A unit of measurement is a specified magnitude of a quantity that is established and used as a standard for measuring other quantities of the same kind. It is determined by convention or regulation.

As given in the problem the  Earth Science students are making a human-scale model of the solar system out on the school playground. The school itself represents the Sun. In the model 1 AU = 100 meters,

As given in the table marks is 1.5 AU far from Mars,

1 AU = 100 meters

1.5 AU = 1.5 × 100

           = 150 meters

Thus, mars would be 150 meters far from the school, therefore the correct answer is option C.

Learn more about the unit of measurement here, refer to the link ;

brainly.com/question/12629581

#SPJ2

what the answer for this question ?

Answers

Answer:

Explanation:

It is better to say “It is correct.” The word THIS is a demonstrative pronoun. The word THIS should be used to point out or to indicate the things. The word CORRECT is an abstract noun therefore it can not be pointed out this is why it is better to say IT IS CORRECT.

A ball is rolling away from you at a constant speed, hits a wall, and then suddenly stops moving. Imagine a position-versus-time graph showing the ball’s motion. Describe the line on the graph.

Answers

Answer:

It would show a "straight line".

Explanation:

Newton's First Law of Motion states that an object at rest will remain at rest and an object in motion will remain in motion (at a constant velocity) unless acted upon by an unbalanced force. Newton's first law of motion is also called the law of inertia.

A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 0.70 ss apart. The speed of sound in air is 343 m/sm/s, and in concrete is 3000 m/sm/s. Part A How far away did the impact occur

Answers

Answer:

271.095 m

Explanation:

✓ Let speed of sound in air that was given as (343 m/s) be represented as (Vi)

✓( speed of sound in concrete that was given as (3000 m/s ) be debited as (Vc)

✓ Let the distance travelled by the sound = s

✓duration of Time that exist between heard of sounds = 0.70s

But we know that

Time = (Distance / Speed)

✓Time it takes the sound to travel through air= s/vi = s/343

✓Time it takes the sound to travel through concrete= s/vc = s/3000

✓ (s/343) - (s/3000) = 0.70

Finding LCM and simplify

[(3000s - 343s)]/1029000 = 0.70

2657s /1029000 = 0.70

Making " s" subject of the formula

s= (1029000 × 0.70)/2657

s=720300/ 2657

s= 271.095 m

Hence, The impact took place at a distance of 271.095 m away from the person.

Suppose that a particle accelerator is used to move two beams of particles in opposite directions. In a particular region, electrons move to the right at 4910 m/s and protons move to the left at 2583 m/s. The particles are evenly spaced with 0.0758 m between electrons and 0.0577 m between protons. Assuming that there are no collisions and that the interactions between the particles are negligible, what is the magnitude of the average current in this region

Answers

Answer:

The answer is "[tex]17.28 \times 10^{-14}\ A[/tex]"

Explanation:

Calculating the number of electrons passing in per second:

[tex]\to n_e = \frac{4910}{0.0758} = 6.4 \times 10^5[/tex]

Calculating the current in electron:

[tex]\to I_e = 6.4 \times 10^5 \times 1.6 \times 10^{-19} = 10.24 \times 10^{-14}\ A[/tex]

Calculating the number of protons passing in per second:

[tex]\to n_p = \frac{2583}{0.0577} = 4.4 \times 10^{4}[/tex]

Calculating the current in proton:

[tex]\to I_p = 4.4 \times 10^{4} \times 1.6 x 10^{-19} = 7.04 \times 10^{-14} \ A[/tex]

Calculating the total current:

[tex]\to I = I_p + I_e = 17.28 \times 10^{-14}\ A[/tex]

How are rainbows made?

Answers

When it rains thin the sun comes out thin a rainbow appears

Answer:

when it rains and at the same time it sunny there would appear a rainbow

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