An experimental arrangement for measuring the thermal conductivity of solid materials involves the use of two long rods that are equivalent in every respect, except that one is fabricated from a standard material of known thermal conductivity kA while the other is fabricated from the material whose thermal conductivity kB is desired. Both rods are attached at one end to a heat source of fixed temperature Tb, are exposed to a fluid of temperature [infinity] T[infinity], and are instrumented with thermocouples to measure the temperature at a fixed distance x1 from the heat source. If the standard material is aluminum, with kA= 200 W/m·K, and measurements reveal values of TA= 75°C and TB= 70°C at x1 for Tb= 100°C and [infinity] T[infinity]= 25°C, what is the thermal conductivity kB of the test material?

Answers

Answer 1

Answer: the thermal conductivity of the second material is 125.9 W/m.k

Explanation:

Given that;

The two rods could be approximated as a fins of infinite length.

TA = 75°C,    θA = (TA - T∞) = 75 - 25 = 50°C

TB = 70°C     θB = (TB - T∞) = 70 - 25 = 45°C

Tb = 100°C    θb = (Tb - T∞) = (100 - 25) = 75°C

T∞ = 25°C

KA = 200 W/m · K ,   KB = ?

Now

The temperature distribution for the infinite fins are given by

θ/θb = e^(-mx)

θA/θb= e^-√(hp/A.kA) x 1  --------------1

θB/θb = e^-√(hp/A.kB) x 1---------------2

next we  take the natural logof both sides,  

ln(θA/θb) = -√(hp/A.kA) x 1 ------------3

In(θB/θb) = -√(hp/A.kB) x 1 ------------4

now we divide 3 by 4

[ ln(θA/θb) /in(θB/θb)] = √(KB/KA)

we substitute

 [ In(50/75) /In(45/75)] = √(KB/200)

In(0.6666) / In(0.6) = √KB / √200

-0.4055/-0.5108 = √KB / √200

0.7938 = √KB / 14.14

√KB = 11.22

KB = 125.9 W/m.k

So the thermal conductivity of the second material is 125.9 W/m.k


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Technician A says that a circuit with continuity reads 0 ohms. Technician B says that an open circuit reads 0 ohms. Who is correct

Answers

Answer:

  A

Explanation:

An open circuit has infinite resistance, not 0. A circuit with continuity usually measures a few ohms or less, depending on the length and gauge of the wire and the condition of the connections. Often, on a general-purpose ohmmeter, the reading is very near 0 ohms.

Technician A is correct.

How can you tell whether a trash container is for regular or biohazardous waste?.

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You can tell whether the trash container is for regular or biohazardous waste by looking at the color of the trash or looking to see if it has an image because a hazardours waste always as a picture on it and is usually colored red.

Explain how to properly engage the safety latches on the Stan Design Pit Jack.

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The way to properly engage the safety latches on the Stan Design Pit Jack is:

Connect the hydraulic jack.Make sure it is properly lubricated.Ensure that the rolling bridge jack is well fused together.Use the machine.

What is the Stan Design Pit Jack?

This refers to the machination which makes use of pit jacks to execute tire rotation in a fast lube pit.

We can note that based on the design, this machine is put in the pit of a car and then rolls back and forth and perform their operations on both the front and real axles.

Hence, it is important to note that the safety latches are designed to prevent work accidents and it is important to properly lubricate the parts to prevent damage.

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A liquid of specific heat 3000J/kgk rise from 15°c to 65°c in 1 min when an electric heater is used. If the heater generate 63000J, calculate the mass of the water​

Answers

Answer:

  0.42 kg

Explanation:

Heat is proportional to mass by way of the conversion factor that is the inverse of the specific heat.

  [tex]\dfrac{63000\text{ J}}{\dfrac{3000\text{ J}}{\text{kg$\cdot$K}}\cdot(65-15)\text{ K}}=0.42\text{ kg}[/tex]

The mass of the liquid is about 0.42 kg.

In lighting system, why it is important to consider maintenance factor?

Answers

Answer: The maintenance factor of a lighting system reflects how much of the initial luminous flux is still available at the end of its useful life. The planned lighting engineer must compute the maintenance factor and multiply the new value of the light output by it.

Explanation:

Answer:

Explanation: A lighting system's maintenance factor indicates how much of the initial luminous flux remains available at the end of its service life. The maintenance factor must be determined by the planning lighting engineer and the new value of the luminous flux multiplied by it.

7)
Given a series silicon diode circuit with the resistor R=2 ko ohms and an applied voltage of 10
V, what is Ipg?
A) 0.5 mA
B) 10 mA
C) 4.65 mA
D) 1.0 mA

Answers

Answer:

  C)  4.65 mA

Explanation:

The series circuit will have a voltage drop of about 0.7 V across the silicon diode, so the voltage drop across the 2 kΩ resistor is 10 -0.7 = 9.3 V. The current through the resistor is given by Ohm's Law:

  I = V/R = 9.3 V/(2 kΩ)

  I = 4.65 mA

From the top of a vertical cliff 80m high, the angles of depression of 2 buoys lying due west of the cliff are 23° and 15° respectively. How far are the buoys apart?​

Answers

Answer:

  110 m

Explanation:

The geometry of the problem can be modeled by a right triangle. The height of the cliff forms one leg, and the distance to a buoy forms the other leg. The angle of depression is opposite the height of the cliff. An appropriate trig relation is ...

  Tan = Opposite/Adjacent

Solving for the Adjacent side (the distance to the buoy), we find ...

  Adjacent = Opposite/Tan

  distance to buoy 1 = (80 m)/tan(23°) ≈ 188.468 m

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Then the distance between the buoys is ...

  298.564 -188.468 m ≈ 110 m

The buoys are about 110 meters apart.

Calculate the current in the coiled heating element of a 240-V stove. The resistance of the element is 60 ohms at its operating temperature.

Answers

Answer:

  4 A

Explanation:

Current is found using Ohm's law.

  I = V/R

  I = (240 volts)/(60 ohms) = 4 A

The heating element current is 4 amperes.

what is this answer Is cereal soup?

Answers

Cereal soup is like spaghetti Os is it soup is it cereal who knows

Answer:

depend what cereal yeha

Explanation:

no explanation

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Answers

Answer:

7 dB

Explanation:

The total loss from the headend to the amplifier input is the sum of the losses along the fiber, that we simply add as they are in dBs:Total Loss = 3 dB + 1 dB + 3 dB = 7 dBThe signal at the amplifier input is just +10 dBm- 7 dB = +3 dBmSo as the output level at the Headend and the one at the output of the neighborhood amplifier must be equal each other (compensating all losses in the path), the amplifier gain must be equal to the cumulative loss, i.e. , 7 dB, so that the amplifier output level be + 10 dBm.

What is rainfall intensity

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Answer:

Rainfall intensity is defined as the ratio of the total amount of rain (rainfall depth) falling during a given period to the duration of the period It is expressed in depth units per unit time, usually as mm per hour (mm/h).

Answer:

the ratio of the total amount of rain (rainfall depth) falling during a given period to the duration of the period

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Less friction loss

Less chance of restriction

More direct routes to boots

All of the above

Answers

I think all of the above
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QUESTION: What does, "Anthropomorphize" means in the sentences above?
(A) It means to program a robot so that it acts in a robotic or unnatural way?
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(C) To make a human act more like an animal and less of a human?
(D) Or to make a human act more like an animal and less of a human?

Answer correctly
Will give Brainliest, a THX, friend request, and will rate ur answer

Answers

Answer:

Hi there

Your answer is:

B.

Explanation:

The "metal contraption", as the text goes on to say, is treated like a friend to Bonnie. Her mom comments on this by contrasting the metal contraption to a puppy.

Hope this helps

B. Or it means to give human characteristics to an object or animal.

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Answers

Answer:

primary consumer because YES

Answer:predator and secondary consumer

Explanation:

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Answers

Answer:

77 lb

Explanation:

Equation: F₁d₁ = F₂d₂

Knowns:

d₁ = 30 ft

F₂ = 105 lb

d₂ = 22 ft

Solving for F₁:

1). F₁•30 = 105•22

2). F₁•30=2,310

3).[tex]\frac{F_1\cdot 30}{30}=\frac{2310}{30}[/tex]

4). F₁ = 77 lb

When a current carrying coil is placed between the magnetic poles a force acts on it that causes it to rotate what can be done to make the coil rotate faster

Answers

Answer:

increase the field strengthincrease the currentdecrease the moment of inertia of the coil

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And the moment of inertia can be decreased by ...

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A) has a self-healing, corrosion-resistant coating.
B) is resistant to galvanic corrosion.
C) is a nonferrous metal.
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Answers

All of the aforementioned are true characteristics and properties of aluminum except: B. is resistant to galvanic corrosion.

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Aluminum can be defined as a silvery white metal and it is considered to be the most abundant metal found in the Earth's crust. Also, it is represented with the chemical symbol "Al" and it has an atomic number of thirteen (13).

This ultimately implies that, aluminum is found in Group 3 on the periodic table because it has three (3) valence electrons, which are found in the outermost shell of its atomic nucleus.

The characteristics and properties of aluminum.

Some of the characteristics and properties of aluminum include the following:

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Answer:

like taking attendance, entering grades, and: communicating with students and parents.

Explanation:

Indeed, the learning management system (LMS) is a multipurpose software application that allows an organization to record, analyze, and distribute information at flexibility.  For example, a school can use this software to take attendance, enter student grades, and can facilitate communication with students and parents.

A rope is wrapped three and a half times around a cylinder. Determine the range of force T exerted on
the free end of the rope for maintaining equilibrium that is required to just support a 5 kN weight. The
coefficient of friction between the rope and the cylinder is 0.2

Answers

The range of force exerted at the end of the rope is; 285.7 N to 1,000 N.

What is the Net horizontal force?

The net horizontal force of the cylinder when it is at equilibrium position can be found by applying Newton's second law of motion. Thus;

∑F = 0

F - μF_n = 0

We are given;

F_n = 5 kN = 5000 N

μ = 0.2

Thus;

F - 0.2(5,000) = 0

F - 1,000 = 0

F = 1,000 N

The strength of the applied force will be increasing as the number of turns of the rope increases. Thus;

Minimum force = Total force/number of turns of rope

Since rope is wrapped three and half times, then;

number of turns = 3.5

Thus;

minimum force = 1,000/3.5

minimum force = 285.7 N

Thus, the range of force exerted at the end of the rope is 285.7 N to 1,000 N.

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explain wet and dry compression tests​

Answers

A wet compression test is similar to a dry compression test except it has the addition of oil placed in each cylinder. A wet compression test is done for two reasons: One or more cylinders has a reading of less than 100 psi on the dry compression test.

What’s is the answer

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I think it’s c because That one makes the most sense

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Engineer's approvall makes it appropriate to alter from the drawing

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Engineering drawing is a document that contain the design of an engineer represented in a sketch.

deviating fron the drawing is same as deviating from the design. it is therefore necessary to call the engineers attention before altering the drawing.

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whats your answer Where is the strangest place you’ve urinated or defecated?

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Answer:At the train station

Explanation:

Answer:

in those camping portal pottys

At time t the resultant force on a particle, of mass 250kg is (300ti-400tj)N. Initially, the particle is at the origin and is moving

with the velocity (2i-3j)m

−1

Answers

Answer:

i

Explanation:

a. An 80-percent efficient pump with a power input of 20 hp is pumping water from a lake to a nearby pool at ar ate of 1.5 ft3 /s through a constant-diameter pipe. The free surface of the pool is 80 ft above that of the lake. Determine the mechanical power used to overcome frictional effects in piping.

b. Water is pumped from a lake to a storage tank 15 m above at a rate of 70 L/s while consuming 15.4 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy. Determine:

1. The overall efficiency of the pump–motor unit.
b. The pressure difference between the inlet and the exit of the pump.

Answers

Answer:

A) mechanical power used to overcome frictional effects in piping = 2.373 HP

B) efficiency = 66.82%

Pressure difference = 147 KPa

Explanation:

We are given;

efficiency of pump; η = 80% = 0.8

power input of pump;P_pump,in = 20 hp

rate being pumped; Q = 1.5 ft³/s = 0.04248 m³/s

free surface of pool; Δz = 80 ft = 24.384 m

mechanical pumping power used to deliver water is;

W_u = η × P_pump,in

W_u = 0.8 × 20

W_u = 16 Hp

Now, change in total mechanical energy of water will be equal to the change in potential energy.

Thus, it is expressed as;

ΔE_mech = ρ × Q × g × Δz

Where ρ is density of water = 1000 kg/m³

Thus;

ΔE_mech = 1000 × 0.04248 × 9.81 × 24.384 = 10,161.5150592 J/s

Converting to HP gives;

ΔE_mech = 13.627 HP

Now, mechanical power used to overcome frictional effects is given by;

W_frict = W_u - ΔE_mech

W_frict = 16 - 13.627

W_frict = 2.373 HP

B) We are now given;

W_elect,in = 15.4 KW

Volumetric flow rate; q = 70 l/s = 0.07 m³/s

Height; h = 15 m

Mass flow rate; m' = qρ

Where ρ is density of water = 1000 kg/m³.

m' = 0.07 × 1000

m' = 70 kg/s

Now,

ΔE_mech = workdone through height of 15m

Thus;

ΔE_mech = m'gh

ΔE_mech = 70 × 9.8 × 15

ΔE_mech = 10,290 W = 10.29 Kw

efficiency of the pump–motor unit = ΔE_mech/(W_elect,in) = 10.29/15.4 = 0.6682 or 66.82%

Pressure difference = ρgh = 1000 × 9.8 × 15 = 147,000 Pa = 147 KPa

Refrigerant-134a at 1 MPa and 100 C is to be cooled to 1 MPa and 28 C in a condenser by air. The air enters at 125 kPa and 25 C with a mass flow rate of 697 kg/min and leaves at 97 kPa and 58 C. Determine the mass flow rate of the refrigerant. Assume air has a constant heat capacity determined at room temperature. Report the mass flow rate of the refrigerant in kg/min with one decimal digit, for example 95.3 or 105.6.

Answers

I don’t know but it might be a lot

How long would a piece of wood need to be to make a diagonal brace for a rectangle that measures 4 inches by 3 inches? Use the Pythagorean theorem, a² + b² = c², to determine the answer. 5 inches 7 inches 12 inches 25 inches Select the correct answer.

Answers

Answer:

Length of a diagonal = 5 inches

Explanation:

Let [tex]a[/tex] and [tex]b[/tex] the sides of the rectangle and [tex]c[/tex] be the diagonal of the rectangle.

According to the Pythagorean theorem, sum of squares of base and perpendicular is equal to the square of hypotenuse.

As each angle of the rectangle is a right angle,

[tex]a^2+b^2=c^2[/tex]

Put [tex]a=4\,,\,b=3[/tex]

[tex]4^2+3^2=c^2\\16+9=c^2\\25=c^2\\\sqrt{25}=c\\ 5=c[/tex]

So,

Length of a diagonal = 5 inches

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