The temperature of a gas stream is to be measured by a thermocouple whose junction can beapproximated as a 1.2-mm-diameter sphere. The properties of the junction are k =35 W/m °C, p=8500kg/m3, and Cp = 320 J/kg °C, and the heat transfer coefficient between the junction and the gas is h=65W/m2 °C. Determine how long it will take for the thermocouple to read 99 percent of the initialtemperature difference. (∅/∅i= 0.01)
Answers
it will take 30.65 minutes for the thermocouple to read 99 percent of the initial temperature difference. (∅/∅i = 0.01).
The temperature of a gas stream is to be measured by a thermocouple whose junction can be approximated as a 1.2-mm-diameter sphere. So, the radius, r = 0.6 mm = 0.0006 m, the volume of the sphere, V = (4/3)πr³, and the area of the sphere, A = 4πr².
The properties of the junction are k = 35 W/m °C, p = 8500 kg/m³, and Cp = 320 J/kg °C, and the heat transfer coefficient between the junction and the gas is h = 65 W/m² °C.
We have, thermal conductivity of the sphere = k = 35 W/m °C, density of the sphere = p = 8500 kg/m³, specific heat of the sphere = Cp = 320 J/kg °C, and heat transfer coefficient between the sphere and the gas, h = 65 W/m² °C.
The initial temperature difference is given by, ΔT₀ = 1°C = 1 K. Let, the time taken for the thermocouple to read 99% of the initial temperature difference, ΔT99 = 0.99 K.
Let, the thermal diffusivity of the sphere be,
α = k / (pCp) = (35 W/m °C) / (8500 kg/m³ x 320 J/kg °C) = 0.000012868 m²/s.
And, the Biot number is given by, Bi = (h x A) / k = [(65 W/m² °C) x 4π(0.0006 m)²] / (35 W/m °C) = 0.0492.
The equation for the unsteady-state temperature profile of a sphere is, θ(r,t) = Σ [(-1)n+1 / n] exp(-n²π²αt / r²) sin (nπr / R), where R is the radius of the sphere. We can estimate the time taken for the thermocouple to read 99% of the initial temperature difference using a semi-log plot of θ/ΔT vs. t/ti.
This plot is linear and of the form, θ/ΔT = 1 - A exp (-Bt/ti), where A = 0.01 and B = (nπ/R)².So, θ/ΔT = 0.99 = 1 - A exp (-Bt/ti), or 0.01 exp (-Bt/ti) = 0.01/0.99, or exp (-Bt/ti) = 1/99, or -Bt/ti = ln (1/99), or t/ti = ln (99).
Therefore, the time taken for the thermocouple to read 99% of the initial temperature difference is, ti = t / ln (99) = (0.000012868 m²/s) (0.6 mm)² / (35 W/m °C) ln (99) = 1838.98 s or 30.65 minutes.
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Related Questions
what converts electrical energy into mechanical energy?
Answers
An electric motor is an electrical machine that converts electrical energy into mechanical energy.
It works on the principle of electromagnetic induction, where a current-carrying conductor placed in a magnetic field produces a mechanical force.
Electric motors are commonly used in applications such as household appliances, power tools, and vehicle propulsion systems. They come in a variety of sizes and power ratings, and are used in industrial, automotive, and consumer applications. The most common type of electric motor is the induction motor, which utilizes a rotating magnetic field to produce torque.
Other types of electric motors include brushless DC motors, direct current motors, and synchronous motors. Electric motors are able to generate high torque even at low speeds, making them efficient for a variety of applications. Their versatility and easy maintenance make them popular for both consumer and industrial applications.
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An object is attached to a vertical spring and bobs up and down between points A and B. Where is the object located when its kinetic energy is a maximum? Midway between A and B one-third of the way between A and B one-fourth of the way between A and B at either A or B at none of the above points
Answers
When an object is attached to a vertical spring and oscillates between points A and B, its kinetic energy reaches a maximum midway between these points.
This is because the object's potential energy is highest at points A and B, while its kinetic energy is lowest at these points. As the object moves from A to B, the potential energy decreases and is converted into kinetic energy, which increases.
When the object reaches the midpoint between A and B, the potential energy and kinetic energy are equal, and the object's kinetic energy is at its maximum. So, the correct answer is that the object is located midway between points A and B when its kinetic energy is at its maximum.
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In an RCL circuit a second capacitor is added in parallel to the capacitor already present. Does the resonant frequency of the circuit increase, decrease, or remain the same
Answers
When a second capacitor is added in parallel to the existing capacitor in an RCL circuit, the resonant frequency of the circuit remains the same. Option C is correct answer.
In an RCL circuit, the resonant frequency is determined by the values of the inductor (L) and the capacitor (C) in the circuit. When a second capacitor is added in parallel, it increases the total capacitance of the circuit. However, the resonant frequency depends on the product of the inductance and the total capacitance.
Since the inductor value (L) remains the same and the total capacitance (C_total) increases due to the additional capacitor in parallel, the resonant frequency (f_resonant) remains unchanged resistance. The resonant frequency is given by the equation:
\(f_resonant = 1 / (2\pi \sqrt{(L *Ctotal)} )\)
By adding a capacitor in parallel, the total capacitance increases but it does not affect the inductance. Therefore, the resonant frequency remains the same.
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The Complete question is
In an RCL circuit a second capacitor is added in parallel to the capacitor already present. Does the resonant frequency of the circuit
A. increase,
B. decrease, or
C. remain the same
The __________ notation of entity-relationship modelling can be used for both conceptual and implementation modelling.
a. Bachman
b. UML
c. Chen
d. Crow's Foot
Answers
The Chen notation of entity-relationship modelling can be used for both conceptual and implementation modelling.
The Chen notation of entity-relationship modelling can be used for both conceptual and implementation modelling. Notation refers to the symbols and conventions used to represent concepts in a model. Entity-relationship modelling is a technique used in database design to represent the relationships between entities. Conceptual modelling is the process of creating a high-level representation of a system, while implementation modelling involves creating a detailed representation of the system's implementation.
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how could you test the idea that solar enefgy is required for the hydrolisis of water during phtotosyntheiss
Answers
One way to test this hypothesis would be to conduct an experiment in which water is subjected to light sources of varying intensity.
What is phtotosyntheiss?Photosynthesis is a process used by plants and some other organisms to convert light energy, typically from the sun, into chemical energy that can be used to fuel biological processes. During photosynthesis, light energy is absorbed by chlorophyll molecules in the plant's leaves and is then used to convert carbon dioxide and water into sugars and oxygen. This process provides the oxygen we breathe and the food we eat, making it one of the most important processes on Earth.
During the experiment, the rate of hydrolisis can be measured, and this data can then be compared to determine if the energy from the solar source is required for hydrolisis. Additionally, a control experiment can be conducted using light sources that do not contain solar energy, such as a light bulb, to compare to the solar energy experiment. This will allow scientists to determine the effect of the solar energy on the rate of hydrolisis, and confirm or refute the hypothesis.
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It is given that m is the midpoint of and . midpoints divide a segment into two congruent segments, so . since and perpendicular lines intersect at right angles, and are right angles. right angles are congruent, so . the triangles share , and the reflexive property justifies that . therefore, by the sas congruence theorem. thus, because _____________. finally, δpkb is isosceles because it has two congruent sides. corresponding parts of congruent triangles are congruent base angles of isosceles triangles are congruent of the definition of congruent segments of the definition of a right triangle
Answers
The triangle PKB is isosceles because it has two congruent sides. Corresponding parts of congruent triangles are congruent, so base angles PK and KB are congruent. This follows from the definition of congruent segments and the definition of a right triangle.
It is given that m is the midpoint of segment AB and segment CD, so AB = CD. Since AB and CD are perpendicular lines, angle AMB and angle DMC are right angles. Right angles are congruent, so angle AMB = angle DMC.
The triangles share angle AMB, and the reflexive property justifies that triangle AMB is congruent to triangle DMC. Therefore, by the SAS Congruence Theorem, triangle AMB is congruent to triangle DMC.
Thus, because triangle AMB is congruent to triangle DMC, the sides AM and MB are congruent to the sides DM and MC.
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Don't mind this, just figuring something out
Answers
Answer:
ok
Explanation:
Have a nice day!
An inelastic collision is one in which:
kinetic energy before the collision equals kinetic energy after the collision.
kinetic energy after the collision is zero.
kinetic energy before the collision is less than kinetic energy after the collision.
kinetic energy before the collision is greater than kinetic energy after the collision.
Answers
Answer:
kinetic energy before the collision is greater than kinetic energy after the collision.
Explanation:
An inelastic collision is Kinetic energy before the collision is greater than kinetic energy after the collision.
Kinetic energy before the collision is more than after the collision in an inelastic collision. Some of the initial kinetic energy is lost in an inelastic collision, usually transformed into heat or sound. Colliding objects stick together or deform, decreasing their aggregate kinetic energy. This type of collision commonly loses energy due to internal forces or friction. The system's total kinetic energy is lowered in an inelastic collision, unlike an elastic collision. Many real-world collisions are inelastic due to energy dissipation and deformation.
In an inelastic collision, some kinetic energy is lost, and the objects stick together or deform during the collision. The final kinetic energy is less than the initial kinetic energy, resulting in less total mechanical energy after the collision compared to before the collision.
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A person covers 90kms in 2 hours and 30 minutes find the speed in meters per second
Answers
Answer:i think you need to divide
Explanation:
A blimp has a buoyant force of 54400 N acting on it. What is its volume?
70 Points
HELP FAST PLEASE!!!
Answers
The buoyant force of 55400 N acting on the blimp and the volume of the blimp is 4527 m³.
The buoyant force is the upward force experienced by an object when the object is immersed in the fluids. It is obtained from the product of density, volume, and acceleration due to gravity(g).
From the givens,
Fb = ρ×V×g
Fb (the buoyancy force) = 54400 N
ρ (the density of the fluid (air)) = 1.225 kg/m³
V (volume of the fluid) =?
g (acceleration due to gravity) = 9.81 m/s²
V = Fb / ρ×g
= 54400 / (1.225×9.81)
= 4526.7 m³.
The volume V of the blimp is 4526.7 m³.
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The x coordinate of an electron is measured with an uncertainty of 0.240 mm.1 mm=10−3 m. Use the following expression for the uncertainty principle: ΔxΔpx≥ℏ, ℏ=2πh, where h is Planck's constant. Use h= an electron is 9.11×10−31 kg. Part A - What is the minimum uncertainty in the electron's momentum? Use scientific notations in the format of 1.234∗10n in kg⋅m/s. uncertainty in momentum = kg⋅m/s Part B - What is the minimum uncertainty in the electron's velocity? Enter a regular number with 4 digits after the decimal point in m/s.
Answers
The minimum uncertainty in the electron's velocity is 18.9655 m/s.
Part A - Uncertainty in the electron's momentum. The uncertainty principle is ΔxΔpx≥ℏ, where ℏ=2πh, where h is Planck's constant. It is given that the uncertainty in the x coordinate of an electron is 0.240 mm, and 1 mm = 10-3 m. We know that the minimum uncertainty in the electron's momentum is equal to:
Δpx ≥ ℏ / Δxwhere ℏ
= 2πh
= 2π × 6.626 × 10-34 = 4.142 × 10-33 kg m²/s.
Now,Δpx ≥ ℏ / Δx= (4.142 × 10-33) / (0.240 × 10-3)= 1.7267 × 10-29 kg m/s
Hence, the minimum uncertainty in the electron's momentum is 1.7267 × 10-29 kg m/s.
Part B - Uncertainty in the electron's velocityVelocity v and momentum p are related by p = mv, where m is the mass of the object. We know that the minimum uncertainty in the electron's momentum is 1.7267 × 10-29 kg m/s from Part A. The mass of an electron is 9.11 × 10-31 kg. Therefore, the minimum uncertainty in the electron's velocity is:
v = p / m
= (1.7267 × 10-29) / (9.11 × 10-31)
= 18.9655 m/s
Since we need to enter a regular number with 4 digits after the decimal point in m/s, rounding off the value to 4 decimal places, we get:
v = 18.9655 ≈ 18.9655 m/s.
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this is a type of protein that helps to speed up metabolic reactions while remaining unchanged.
Answers
Answer:
A fundamental task of proteins is to act as enzymes—catalysts that increase the rate of virtually all the chemical reactions within cells.
what is si4h10 si3h8 higher boiling point?
Answers
The compound with the higher boiling point is Si4H10. This is because it has a larger molecular weight and a larger surface area, leading to stronger intermolecular forces and a higher boiling point.
The boiling point of a substance is determined by the strength of the intermolecular forces between its molecules. Larger molecules have stronger intermolecular forces because they have a larger surface area for the forces to act upon. This is why larger molecules generally have higher boiling points.
In the case of Si4H10 and Si3H8, Si4H10 has a larger molecular weight and a larger surface area, leading to stronger intermolecular forces and a higher boiling point.
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a 0.40 a current is passing through a 141-ω resistor. what is the power (in w) dissipated in the resistor? do not include units with your answer.
Answers
The power dissipated in a 141-Ω resistor with a current of 0.40 A can be calculated using the formula P = I^2 * R. The power is equal to 0.064 W.
To calculate the power dissipated in a resistor, we can use the formula P = I^2 * R, where P is the power, I is the current, and R is the resistance.
Given that the current passing through the resistor is 0.40 A and the resistance is 141 Ω, we can substitute these values into the formula:
P = (0.40 A)^2 * 141 Ω
P = 0.16 A^2 * 141 Ω
P = 0.064 W
Therefore, the power dissipated in the resistor is 0.064 W.
This calculation is based on the relationship between current, resistance, and power in an electrical circuit. The power dissipated in a resistor is directly proportional to the square of the current and the resistance.
In this case, the given values of current and resistance allow us to determine the power dissipated in the resistor as 0.064 W.
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help please, i don't know what the answer is but i accidently clicked D .....
Answers
Answer:
You are right correct option is D.
An element has a charge of -3, has 8 protons, 11 neutrons, and electrons
Word Bank:
12 5 11 8 13
pls help
Answers
If it’s asking the no of electrons then -
No of electrons =no of protons in an atom of a element ....therefore there are 11 electrons
Rooms are fitted with ventilators to let the air move around. The phenomenon involved is:
a. conduction
b. Convection
c. radiation
d. condensation
Answers
Answer:
B. Convection
Explanation:
Convection is the process in which heat is transferred from one point to another by the actual movement of the material particles from a region of high temperature to a region of low temperature.
Is a 5kg ball is rolling to the right and has a velocity of 4 m/s what is the momentum of the ball
Answers
Answer:
∆p = 20 kg * m/s
Explanation:
The change in momentum is the mass of the body multiplied by the change in its velocity.
In formula form ∆p = m * ( ∆v ).
with m = 5 kg and ∆v = 4 m/s
∆p = 5 kg * 4 m/s
∆p = 20 kg * m/s
What is the total resistance in a series circuit consisting of three resistances: 1 Ohm, 2Ohms, and 10Ohms?
A) 13Ohms
B) 23 Ohms
C) 0.75Ohms
D) 1.6 Ohms
E) 10.0Ohms
Answers
The total resistance in a series circuit is equal to the sum of the individual resistances. Therefore, the total resistance in this circuit would be 1 + 2 + 10 = 13 Ohms. So the answer is A) 13 Ohms.
the total resistance in a series circuit consisting of three resistances: 1 Ohm, 2 Ohms, and 10 Ohms.
To find the total resistance in a series circuit, you simply add the individual resistances together.
Add the resistances
1 Ohm + 2 Ohms + 10 Ohms = 13 Ohms
So, the total resistance in this series circuit is 13 Ohms.
The total resistance in a series circuit is equal to the sum of the individual resistances. Therefore, the total resistance in this circuit would be 13 Ohms.
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an amoeba has 2.10 ✕ 1016 protons and a net charge of 0.800 pc. (a) how many fewer electrons are there than protons? (b) If you paired them up, what fraction of the protons would have no electrons?
Answers
a) there are 20,500,000,000 fewer electrons than protons.
b) If you paired them up, the fraction of protons that have no electrons is 2.05 × 10¹⁰
(a) Calculation of fewer electrons than protons in an amoeba:
We know that,The number of protons = 2.10 × 1016
Charge on an amoeba = 0.800 pc
The formula for finding the charge of an amoeba is,
Charge = (No. of protons) - (No. of electrons) × (Charge on an electron)
0.800 pc = (2.10 × 1016) - (No. of electrons) × (1.6 × 10−19C)
No. of electrons = 2.05 × 10¹⁰
(b) Fraction of protons that have no electrons:One electron is paired up with one proton. Hence, the number of electrons with no pair will be the same as the number of protons that have no pair.
Therefore, the fraction of protons that have no electrons = Number of protons with no electrons/Total number of protons= Number of electrons/Total number of protons= 2.05 × 1010/2.10 × 1016= 0.0000976
This fraction can also be represented as 9.76 × 10⁻⁵.
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11. Calculate the resultant force acting on the objects below:
a)
12 N
6 N
Answers
Answer:I would say the answer is either 6 N or 18 N
Explanation: SINCE YOUR QUESTION ISN'T SPECIFIC I can't answer it accurately mind providing a diagram or picture of the question or the direction of the forces
a 1020-hertz sound wave travels at 340 m/s in air with a wavelength of a) 30 m. b) 3 m. c) 0.333 m. d) 1 m. e) none of the above choices are correct.
Answers
The wavelength of the sound wave is equal to 0.333 m. Therefore, option (c) is correct.
What are frequency and wavelength?The frequency of the wave can be defined as the number of oscillations that occur in one second and can be expressed in hertz. The wavelength can be defined as the distance between the two adjacent points of a wave such as two crests or troughs.
The relationship between frequency (ν), speed of sound waves (V), and wavelength (λ):
V = νλ
Given, the frequency of the sound wave, ν = 10 Hz
The speed of the sound wave,\(V = 340 m/s\)
The wavelength of the sound waves can determine as follows
λ = V/ν = 340/1020 = 0.333 m.
Therefore, the wavelength of the sound wave is 0.333 m
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A 45 kg object has a momentum of 225 kg-m/s northward. What is the object's velocity?
Answers
Answer: 5 m/s North
Explanation:
Velocity = Momentum/Mass
Velocity = 225 kg*m/s/45kg
Velocity = 5 m/s North
When astronomers say that the groups of galaxies are distributed isotropically, they mean that?
Answers
When astronomers say that the groups of galaxies are distributed isotropically, they mean that the group of galaxies appears to be similar when viewed through any directions.
Isotropy of galaxies means that the arrangement of galaxies doesn't differ in any directions. That is ,the galaxies are arranged in such a way that it seems same even if viewed from different directions. The word isotropy refers to the lack of preference to the direction.
In Cosmology, the universe is also said to have isotropy and homogeneity. Homogeneity also refers to the uncertainty of location.
In astronomy, the isotropy of galaxies simply means there will be no difference in the galaxies viewed from different directions.
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A car on flat ground accelerates at 0.785 m/s2 when a net force of 1050 N acts on it. How much normal force acts on it?
Answers
Answer:
13108.3N
Explanation:
Given parameters:
Acceleration = 0.785m/s²
Net force = 1050N
Unknown:
Normal force acting on car = ?
Solution:
The normal force on this car is the weight of the car;
Normal force = mg
where m is the mass of the car
g is the acceleration due to gravity = 9.8m/s²
Now solve for the mass;
Net force = mass x acceleration
1050 = mass x 0.785
mass = \(\frac{1050}{0.785}\) = 1337.6kg
So,
Normal force = 1337.6kg x 9.8m/s² = 13108.3N
13108 works as well for acellus
The total mass of water vapor stored in the atmosphere atany one moment is about _______ of the world's supply of precipitation.
Answers
The total mass of water vapor stored in the atmosphere at any one moment is a relatively small fraction of the world's supply of precipitation.
This is because the atmosphere can hold only a limited amount of water vapor compared to the total amount of water available on Earth. The majority of Earth's water is found in the oceans, lakes, rivers, and underground reservoirs.
The amount of water vapor in the atmosphere can vary depending on factors such as temperature, humidity, and weather patterns.
However, even at high humidity levels, the mass of water vapor in the atmosphere is still significantly less than the total amount of precipitation that occurs worldwide, which includes rainfall, snow, and other forms of precipitation.
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At which points in space does destructive interference occur for coherent electromagnetic waves (EM waves) with a single wavelength λ ? A. where their path length differences are 2λ B. where their path length differences are λ C. where their path length differences are even integer multiples of λ/2 D. where their path length differences are odd integer multiples of λ/2
Answers
Therefore, the correct option is D, where their path length differences are odd integer multiples of λ/2.
The correct answer to the given question is option D, where their path length differences are odd integer multiples of λ/2.In interference, two waves meet with each other, and the amplitude of the resultant wave depends on the phase difference between the two waves.
In the case of constructive interference, the phase difference between the two waves is a multiple of 2π, and in destructive interference, the phase difference is a multiple of π. For electromagnetic waves, destructive interference occurs when the path length difference between two waves is an odd integer multiple of half of the wavelength.
The expression for destructive interference can be written as follows:Δx = (2n + 1)λ/2Here, Δx represents the path length difference, n represents an integer, and λ represents the wavelength of the wave.Therefore, the correct option is D, where their path length differences are odd integer multiples of λ/2.
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When two forces act in the same direction on an object, the net force is found by ....................the forces.
1. adding
2.subtracting
3.multipling
4.dividing
Answers
Answer:
By ADDING the forces
Explanation:
Below are statements about electrical current. Check ALL the statements that are true. A resistor can get hot when a current flows through it. A light bulb has a non-negligible resistance. The unit of resistance is C/m2 The unit of resistance is the Ohm.
Answers
A resistor can get hot when a current flows through it, and the unit of resistance is the Ohm.
What are some properties of electrical current?
When an electric current flows through a resistor, it can generate heat. This phenomenon occurs due to the resistance offered by the resistor to the flow of electrons. When the electrons pass through the resistor, they collide with atoms and molecules, transferring their kinetic energy and resulting in an increase in temperature. This heating effect is commonly observed in various electronic devices, such as heaters or incandescent light bulbs.
Additionally, the unit of resistance in the International System of Units (SI) is the Ohm, represented by the symbol Ω. Resistance is a fundamental property of electrical components, describing their ability to impede the flow of electric current. It is calculated by dividing the voltage across a component by the current passing through it, according to Ohm's law.
Learn more about electrical current, resistance, and Ohm's law to deepen your understanding of these essential concepts in electrical engineering and physics.
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___________,_________, and ________ are the three regions on the periodic table
Please help I’m suppose to fill in the blanks.
Answers
Answer:
metal, metalloid, and non-metals are the 3 regions on the periodic table
Explanation:
Answer:
Halogens, Akali, and noble gases
Explanation: