One of my tools stopped working, and I found that in order to fix it, I need to replace a broken wire. The broken wire has a diameter of 5mm and a length of 15 cm. When it was connected to the battery, a current of 12.5mA flowed through the wire. The only wire that I have at home is the same material, but has a diameter of 2mm.
a) If I replace the broken piece of wire with a 15cm length of my 2mm diameter wire, what will happen to the current (increase or decrease)?
What is the value of the current through the new wire (assume that it’s connected to the same battery as the original wire)? Hint: Think about the resistances of the old and new wires.
b) How long should the new wire (2mm diameter) be if I want to ensure that the current passing through it is the same as the original wire (12.5mA)?

Answers

Answer 1

Answer:

a) I₂ = 2 mA   (The current has decreased)

b) L₂ = 2.4 cm

Explanation:

Consider the old wire as wire 1 and the new wire as wire 2. The data that we have from the question is:

Current through wire 1 = I₁ = 12.5 mA

Diameter of wire 1 = d₁ = 5 mm

Length of wire 1 = L₁ = 15 cm

Cross-Sectional Area of wire 1 = A₁ = πd₁²/4 = π(5 mm)²/4 = 19.63 mm²

Diameter of wire 2 = d₂ = 2 mm

Cross-Sectional Area of wire 2 = A₂ = πd₂²/4 = π(2 mm)²/4 = 3.14 mm²

a)

Length of wire 2 = L₂ = 15 cm

Since, the battery is same. Therefore, the voltage will be same for both wires.

V₁ = V₂

using Ohm's Law (V = IR)

I₁R₁ = I₂R₂

Since resistance of wire is given by formula:  R = ρL/A

Therefore,

I₁ρ₁L₁/A₁ = I₂ρ₂L₂/A₂

where,

ρ = resistivity, and it depends upon material of wire and the material of both wires is same and the length of wires is also same.

Hence,    ρ₁ = ρ₂

and      L₁ = L₂

and the equation becomes:

I₁/A₁ = I₂/A₂

I₂ = I₁A₂/A₁

I₂ = (12.5 mA)(3.14 mm²)/(19.63 mm²)

I₂ = 2 mA

Thus, the current has decreased.

b)

In order to have same current the resistance of both wires must be same:

R₁ = R₂

ρ₁L₁/A₁ = ρ₂L₂/A₂

Since,   ρ₁ = ρ₂

Therefore,

L₁/A₁ = L₂/A₂

L₂ = L₁A₂/A₁

L₂ = (15 cm)(3.14 mm²)/(19.63 mm²)

L₂ = 2.4 cm


Related Questions

what is the meaning of ultrametric problem?


Answers

The large majority of optimization problems related to the inference of distance‐based trees used in phylogenetic analysis and classification is known to be intractable.

For Figure Below, if the elevation of the benchmark A is 25.00 m above MSL:
1. Using the Rise and Fall Method, find the reduced level for all points. (Construct the Table)
2. Using HPC Method, find the reduced level for all points. ( Construct the Table).
3. Show all required Arithmetic checks for your work. For Item 1 and 2.
4. What is the difference in height between points H and D?
5. What is the gradient of the line connecting A and J, knowing that horizontal distance = 200
m.

Answers

Answer:

For Figure Below, if the elevation of the benchmark A is 25.00 m above MSL:

1. Using the Rise and Fall Method, find the reduced level for all points. (Construct the Table)

2. Using HPC Method, find the reduced level for all points. ( Construct the Table).

3. Show all required Arithmetic checks for your work. For Item 1 and 2.

4. What is the difference in height between points H and D?

5. What is the gradient of the line connecting A and J, knowing that horizontal distance = 200

m.

The most common type of pressure gauge is the 1. Piston 2. Linkage 3. Bourdon Tube 4. 5. Temperature​

Answers

Answer:

Bourdon Tube gauge

Explanation:

The most popular type of pressure gauge in several countries is the Bourdon pressure tube gauge, that is used to determine medium and high loads. Bourdon tube  will measure pressures ranging between 600 mbar - 4,000 bar. While the inner pressure is greater than the exterior pressure, the tube pushes forward, and vise versa.

technician a cleans brake components in denatured alcohol. technician b cleans brake components in clean brake fluid. who is correct?

Answers

Both technicians may be correct depending on the situation and the type of brake components being cleaned with either denatured alcohol or brake fluid.


Denatured alcohol is a common solvent used to clean brake components as it effectively removes brake dust, dirt, and grime. It is also less harmful to the environment and safer to use than other harsh solvents. However, it may not be effective in removing certain types of brake fluid or oil-based contaminants.

On the other hand, clean brake fluid can also be used to clean brake components as it is specifically designed to lubricate and protect brake parts. It may be more effective in removing brake fluid or oil-based contaminants, but it can be more expensive and may not be as readily available as denatured alcohol.

Ultimately, the choice of solvent for cleaning brake components depends on the specific situation and the type of contaminants that need to be removed. A knowledgeable technician will be able to determine the best solvent to use based on their experience and expertise.

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Technician A is correct when cleaning brake components in denatured alcohol.

Using denatured alcohol is an appropriate method for cleaning brake components, as it effectively removes dirt, grease, and contaminants without damaging the components.

On the other hand, Technician B is not correct, as cleaning brake components in clean brake fluid is not recommended because it may not effectively remove all contaminants and can cause issues with the braking system.

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Floyd’s Bumpers has distribution centers in Lafayette, Indiana; Charlotte, North Carolina; Los Angeles, California; Dallas, Texas; and Pittsburgh, Pennsylvania. Each distribution center carries all products sold. Floyd’s customers are auto repair shops and larger auto parts retail stores. You are asked to perform an analysis of the customer assignments to determine which of Floyd’s customers should be assigned to each distribution center. The rule for assigning customers to distribution centers is simple: A customer should be assigned to the closest center. The worksheet Floyds in the provided datafile contains the distance from each of Floyd’s 1,029 customers to each of the five distribution centers. Your task is to build a list that tells which distribution center should serve each customer. The following functions will be helpful: =MIN(array). The MIN function returns the smallest value in a set of numbers. For example, if the range A1:A3 contains the values 6, 25, and 38, then the formula =MIN(A1:A3) returns the number 6, because it is the smallest of the three numbers: =MATCH(lookup_value, lookup_array, match type). The MATCH function searches for a specified item in a range of cells and returns the relative position of that item in the range. The lookup_value is the value to match, the lookup_array is the range of search, and match type indicates the type of match (use 0 for an exact match). For example, if the range A1:A3 contains the values 6, 25, and 38, then the formula =MATCH(25,A1:A3,0) returns the number 2, because 25 is the second item in the range. =INDEX(array, column_num). The INDEX function returns the value of an element in a position of an array. For example, if the range A1:A3 contains the values 6, 25, and 38, then the formula =INDEX(A1:A3, 2) 5 25, because 25 is the value in the second position of the array A1:A3. (Hint: Create three new columns. In the first column, use the MIN function to calculate the minimum distance for the customer in that row. In the second column use the MATCH function to find the position of the minimum distance. In the third column, use the position in the previous column with the INDEX function referencing the row of distribution center names to find the name of the distribution center that should service that customer.) Click on the datafile logo to reference the data. (Hint: The INDEX function may be used with a two-dimensional array: =INDEX(array, row_num, column_num), where array is a matrix, row_num is the row numbers and column_num is the column position of the desired element of the matrix.) Floyd's Bumpers pays a transportation company to ship its product to its customers. Floyd's Bumpers ships full truckloads to its customers. Therefore, the cost for shipping is a function of the distance traveled and a fuel surcharge (also on a per mile basis). The cost per mile is $2.72 and the fuel surcharge is $.56 per mile. The worksheet May in the provided datafile contains data for shipments for the month of May (each record is simply the customer zip code for a given truckload shipment), as well as the distance table from the distribution centers to each customer. Use the VLOOKUP function to retrieve the distance traveled for each shipment from the exercise completed above, and calculate the charge for each shipment. What is the total amount that Floyd's Bumpers spends on these May shipments? If required, round your answers to two decimal places. $ Check My Work Icon Key Previous Question 7 of 7Problem 10-19 Algo (Some Useful Excel Functions for Modeling)

Answers

Consider that it is needed to assign each of Floyd’s customers to a distribution center that is at the closest distance to the customer. The customer zip codes have been given and their distances from each of the five distribution centers in the referred data file “Floyds”.

How to find the shortest distance

Since the interest is in determining the center which is at the shortest distance from the customer, the shortest distance is obtained for each customer. So in the cell G3, use the function written below:

= MIN(B4:F4)

The value obtained is 731. Drag this formula down for all 1029 customers. Now that the minimum distance for each customer has been obtained, it is needed to find out the distribution center for the corresponding distance. For this, first, find the position at which this minimum distance value occurs in the array of five distances. So in cell H4, enter the below formula:

= MATCH (G4, B4; F4, 0)

This function looks for the contents of cell G4 in the range B4 to F4 and returns the position in the array at which it occurs. Since the distance 731 in cell G4 occurs at 1st position in the array of cells from B4 to F4, the function returns value 1 in cell H4. Drag this formula for all 1029 customers.

Step 3/3

Now it is needed to associate each position with the distribution center. For this, use the Index function in cell I4 as below:

= INDEX ($B$2: $F$2, H4)

This function returns the value of the position stated in cell H4 from the range B2 to F2. Now cells B2 to F2 contain the names of all the five distribution centers.

So, by giving this above function, the distribution center is obtained for first customer as Charlotte, NC. Drag this formula for all 1029 customers so that each customer is assigned the nearest distribution center

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Divide. Give the exact answer, written as a decimal. 5) 3.6​

Answers

Answer:

I believe the answer is 0.138

What does Fly-Crash-Fix-Fly describe?
a. Traditional safety program
b. Military concept of loss management
c. Operational Risk Management
d. An airline

Answers

Answer:c. Operational Risk Management

Explanation:

The phrase "Fly-Crash-Fix-Fly" is often used to describe the concept of Operational Risk Management. It emphasizes the continuous cycle of identifying potential risks and hazards (Fly), analyzing and learning from past incidents and accidents (Crash), implementing corrective actions and preventive measures (Fix), and resuming normal operations with improved safety (Fly). This approach aims to proactively manage risks and enhance safety performance within an organization.

While making an online bank transaction, a customer checks to see that the web browser is displaying a lock icon that indicates that an encrypted TCP/IP suite protocol is being used.

Which of the following TCP/IP port numbers does this protocol typically use when the browser encrypts its communications with the bank's web server?

a.25
b.80
c.143
d.443

Answers

Among the given TCP/IP port numbers, the protocol typically uses port number 443 when the browser encrypts its communications with the bank's web server.

So, the correct answer is D.

When a customer makes an online bank transaction, it is essential to ensure that the web browser is displaying a lock icon that indicates that the communication is encrypted.

This encryption protocol is usually a part of the TCP/IP suite protocol.

This port number is reserved for HTTPS (Hypertext Transfer Protocol Secure) traffic, which is the secure version of HTTP used for encrypted communication over the internet. It is crucial to use this protocol to ensure that sensitive information such as banking details and passwords are kept secure from unauthorized access during transmission.

Hence, the answer of the question is D.

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Which items are NOT found on a
door?*
5 points
Cladding
Moulding
Weatherstrip
Check Strap
Striker
All of the above
None of the above

Answers

Answer:

None of the above cause thats what i put

Which of the following units of measurement is denoted by a single apostrophe mark (')?

inch
foot
yard
meter

Answers

Answer:

Foot

Explanation:

It is. trust me

13. What two major safety problems does hydrogen present?

Answers

Answer:

The risks associated with the handling of liquid hydrogen are fire, explosion, asphyxiation and extremely low temperature exposure.

Answer:

fire, explosion, asphyxiation, extremely low temperature exposure/cold burns

Explanation:

consider a stokes flow due to a sphere rotating near a wall, argue from kinematic reversibility weather or not the rotating sphere will experience a force pushing it away or drawing it into the wall

Answers

In Stokes flow, the fluid velocity is proportional to the forces acting on the fluid and the fluid is assumed to be viscous and incompressible. The fluid velocity near a rotating sphere in Stokes flow can be determined using the equations of fluid dynamics.

What is the reversibility about?

Kinematic reversibility is a property of Stokes flow, which states that the fluid flow is symmetric with respect to time reversal. This means that if the fluid velocity is recorded at a certain time, then the same velocity field will be obtained if time is reversed and the flow is replayed in the reverse direction.

When a sphere is rotating near a wall, the flow of fluid around the sphere creates a velocity field that pushes the sphere away from the wall. This flow can be considered as the fluid being pushed away from the sphere and towards the wall. If the flow is time-reversed, the fluid velocity field would be the same, but the direction of the velocity would be reversed. This means that the fluid would be drawn towards the sphere and away from the wall, pulling the sphere towards the wall.

Therefore, based on the property of kinematic reversibility in Stokes flow, the rotating sphere near a wall will experience a force that could either push it away from the wall or draw it towards the wall, depending on the direction of the flow.

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What type of engineer is responsible for assessing the wear and tear of parts used in the manufacturing process?

Civil engineer

Industrial engineer

Materials engineer

Chemical engineer

Answers

The material engineer is in charge of evaluating the wear and tear of manufacturing process components.

How does Materials Engineering work?

Since the beginning of time, new materials have been essential to human development, prosperity, safety, and quality of life. They rank among the greatest achievements of every era. When it comes to civil, chemical, construction, nuclear, aeronautical, agricultural, mechanical, biomedical, or electrical engineering, new materials always open the door to new technologies.

Engineers and scientists who study materials are still at the forefront of numerous scientific fields. Every time we buy or use a new device, machine, or structure, materials science and engineering has an impact on our lives. Our list of recommended readings contains additional information about the impact of this exciting field.) A realization about every application of materials is what gives rise to the academic field of Materials Science and Engineering: The value of the material is determined by its characteristics. A material may be selected for its strength, electrical properties, heat or corrosion resistance, or a variety of other qualities; However, they all involve properties.

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What is "Engineering"?

Answers

Engineering is when both the application of science and math are used to solve problems. An engineer is a person who designs, builds, or maintains engines, machines, or public works. There are six large branches of engineering such as Mechanical, Chemical, Civil, Electrical, Management, and Geotechnical, they all have hundreds of subcategories of engineering under each different branch.

An insulated piston-cylinder device initially contains 0.3m^3 of carbon dioxide at 200 kPa and 27 degrees celcius. An electric switch is turned on, and an 110-V source supplies current to a resistance heater inside the cylinder for a period of 10min. The pressure is held constant during the process, while the volume is doubled. Determine the current that passes through the residual heater.

Answers

The current that passes through the residual heater is 4.94 Ampere.

How to calculate the current passes from the residual heater?

Given,

         Volume = 0.3 m³

         Pressure = 200 kPa

         Temperature = 27°C

         Voltage = 110 V

         Time = 10 minutes

According to the ideal gas equation,

m = PV/RT = 200×10³×0.3/(189×(27+273)) = 1.058 kg

V₁/T₁ = V₂/T₂

T₂ = (V₂/V₂)×T₁ = 2×(27+273) = 600 K = 600 - 273 = 327°C

W = P(V₂ - V₁) = 200×10³ ×(2×0.3 - 0.3) = 60 kJ

Q - W = mCp(T₂ - T₁)

Q - 60 = 1.058×0.839×(327-27)

Q = 326.3 kJ

V×I×t = 326.3 kJ

110×I×(10×60) = 326.3×10³

Current I = 4.94 A

Thus, the current that passes through the residual heater is 4.94 A.

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4.20 Problem in this exercise refer to the following instructions sequence: a. ADD R1, R2, R3 LW R2, 0(R1) LW R1, 4(R1) OR R3, R1, R2. b. LW R1, 0(R1) AND R1, R1, R2 LW R2. 0(R1) LW R1, 0(R3). 4.20.1[5]<4.7> Find all data dependences in this instruction sequences. 4.20.2[10]<4.7> Find all hazards in this sequence for a 5-stage pipeline with and then without fowarding.

Answers

Solution :

Given :

a). ADD \($R1,R2,R1$\)

    LW \($R2, 0(R1)$\)

    LW \($R1, 4(R1)$\)

    OR \($R3,R1,R2$\)

Without forwarding

Only the RAW dependencies can cause data hazards.

The dependencies are :

RAW dependency between instruction 1 and 2 on R1

RAW dependency between instruction 1 and 3 on R1

RAW dependency between instruction 3 and 4 on R1

RAW dependency between instruction 2 and 4 on R2

With forwarding

The result after the execution phase of first instruction is forwarded to second instruction.

So there would not be any dependencies among instruction 1 and 2 and also 1 and 3.

With forwarding the RAW dependencies that can exit only from load to next instruction.

So the dependencies that exit is only between 3 and 4.

The dependencies are  RAW dependencies between instruction 3 and 4 on R1.

b).  LW \($R1,0(R1)$\)

     AND \($R1,R1,R2$\)

     LW \($R2,0(R1)$\)

     LW \($R1,0(R3)$\)

Only RAW dependencies can cause data hazards

The dependencies are

RAW dependency between instruction 1 and 2 on R1

RAW dependency between instruction 1 and 3 on R1

RAW dependency between instruction 2 and 3 on R1

With forwarding

The result after the execution phase of second instruction is forwarded to third instruction.

So there won't be RAW dependencies among instruction 2 and 3.

With forwarding the RAW dependencies that can exist only from load to next instruction.

So dependencies that exists is only between 1 and 2.

Therefore dependencies are RAW dependency between instruction 1 and 2 on R1.

which right flow tube radius resulted in the fastest flow rate?

Answers

The researchers discovered that decreasing the tube radius enhances the flow rate. Because the reduced radius causes the fluid velocity to rise and the fluid to move faster, this is the case.

The right flow tube radius that resulted in the fastest flow rate was 0.5 cm. Flow rate is the quantity of fluid that flows through a channel or pipe in a unit of time, and it is dependent on a variety of factors. These variables include the size of the tube, the viscosity of the fluid, and the pressure gradient across the tube's length. In a study, researchers tested the effect of different flow tube radii on flow rate.

They used a liquid of known viscosity and a pressure gradient, then measured the flow rate using a flowmeter. Three different tube radii, 0.5 cm, 1 cm, and 1.5 cm, were used in the study. The 0.5 cm tube had the highest flow rate.

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How are explosion-proof and flammable refrigerators and freezers different from domestic refrigerators and freezers

Answers

Explosion-proof and flammable refrigerators and freezers are designed to prevent the occurrence of ignition sources or sparks that can lead to explosions.

They are usually used in facilities that handle hazardous materials or in industrial processes that involve combustible gases and chemicals. On the other hand, domestic refrigerators and freezers are intended for residential use and are not built with the same level of safety features.

Here are some differences between these two types of refrigerators and freezers:Design and constructionThe main difference between explosion-proof and flammable refrigerators and freezers and domestic refrigerators and freezers is the design and construction.

Explosion-proof and flammable refrigerators and freezers are designed to prevent the occurrence of ignition sources, sparks, and static electricity that can lead to explosions. The walls of these refrigerators and freezers are made of heavy-duty materials such as steel or cast iron, and the wiring and electrical components are designed to be explosion-proof. Domestic refrigerators and freezers, on the other hand, are not built with the same level of safety features.

The walls of these refrigerators and freezers are usually made of lightweight materials such as plastic or aluminum, and the wiring and electrical components are not designed to be explosion-proof. VentilationAnother difference between these two types of refrigerators and freezers is the ventilation.

Explosion-proof and flammable refrigerators and freezers require proper ventilation to ensure that any flammable gases or vapors are safely removed from the unit. This is achieved through the use of ventilation fans that are built into the unit. Domestic refrigerators and freezers, on the other hand, do not require the same level of ventilation, and the fans are usually used for cooling purposes only.

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Kimber has been tasked with assembling her department's latest updates into a single document. as she combines multiple documents, what's an important word processing skill to know that ensures the end result is organized and easy to use? question 7 options: footnoting animation bookmarking pagination

Answers

When it comes to combining multiple documents, an important word processing skill to know that ensures the final result is organized and easy to use is pagination.

Pagination is a page numbering technique that is done sequentially. These page numbers are usually located at the top or bottom of the web page. In most cases, it is used for main pages and partitions in corporate websites. This kind of design can generally make the user experience simpler on the site. They can also feel more comfortable when it comes to distributing and navigating products within the website.

For example, like this, imagine an e-commerce site that consists of hundreds of product catalogs from various categories. Of course, these products will not be found easily if only placed on one page. As a solution, UI developers and designers can take advantage of pagination to make product placement more structured.

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Problem Statement: Air flows at a rate of 0.1 kg/s through a device as shown below. The pressure and temperature of the air at location 1 are 0.2 MPa and 800 K and at location 2 the pressure and temperature are 0.75 MPa and 700 K. The surroundings are at 300 K and the surface temperature of the device is 1000 K. Determine the rate that the device performs work on its surroundings if the rate of heat transfer from the surface of the device to the environment is 1 kW. Justify your answer. Note that the flow direction for the air is not specified so you need to consider all possibilities for the direction of the airflow. Assume that the air is an ideal gas, that R

Answers

Answer:

The answer is "+9.05 kw"

Explanation:

In the given question some information is missing which can be given in the following attachment.

The solution to this question can be defined as follows:

let assume that flow is from 1 to 2 then

Q= 1kw

m=0.1 kg/s

From the steady flow energy equation is:

\(m\{n_1+ \frac{v^2_1}{z}+ gz_1 \}+Q= m \{h_2+ \frac{v^2_2}{2}+ gz_2\}+w\\\\\ change \ energy\\\\0.1[1.005 \times 800]-1= 0.01[1.005\times 700]+w\\\\w= +9.05 \ kw\\\\\)

If the sign of the work performed is positive, it means the work is done on the surrounding so, that the expected direction of the flow is right.

Problem Statement: Air flows at a rate of 0.1 kg/s through a device as shown below. The pressure and

0/5 pts
Question 2
2nd Problem Statement. At the instant shown, the airplane has a velocity, v= 270 mls in the x direction. The plane has mass 11,00
thrust, T = 110kN, lit, L = 260kN and drag, D = 34. Which of the following equations best represents the sum of forces in the Grection?
T
150
Path
150
Horizontal
mg
Stv

Answers

Explanation:

150 divide by 150 and that how you do the is you what to divide together 15/ 150 you welcome have a good day is you need something else

The maximum surface temperature of the 20-mm-diameter shaft of a motor operating in ambient air at 27°C should not exceed 87°C. Because of power dissipation within the motor housing. It is desirable to reject as much heat as possible through the shaft to the ambient air. In this prob- lem, we will investigate several methods for heat removal. Air T = 27°C -T, S 87°C D A Crad/s) -Shaft, D = 20 mm (a) For rotating cylinders, a suitable correlation for estimating the convection coefficient is of the form Nap = 0.133 Reply (Re) < 4.3 x 109. 0.7 < Pr < 670) where Rep = OD' and 2 is the rotational velocity (rad/s). Determine the convection coefficient and the maximum heat rate per unit length as a function of rota- tional speed in the range from 5000 to 15,000 rpm. (b) Estimate the free convection coefficient and the maximum heat rate per unit length for the station- ary shaft. Mixed free and forced convection effects may become significant for Rep < 4.7(Gr/Pr) Are free convection effects important for the range of rotational speeds designated in part (a)? (c) Assuming the emissivity of the shaft is 0.8 and the surroundings are at the ambient air temperature, is radiation exchange important? (d) If ambient air is in cross flow over the shaft, what air velocities are required to remove the heat rates determined in part (a)? diameter and Solve part(a,b,d) only

Answers

The maximum heat rate per unit length and the convection coefficient as a function of rotational speed is 2.83 kW/m

The effects of mixed convection may become significant.

The exchange of radiation can have a significant impact on heat transfer from the shaft to the surroundings.

How to calculate convection coefficient and the maximum heat?

(a) For rotating cylinders, the correlation for estimating the convection coefficient is given by:

Nap = 0.133 Rep^0.6 Pr^0.4

where Rep = OD' and Pr is the Prandtl number. For air at 27°C, Pr = 0.71 and OD = 20 mm.

The rotational speed in the range from 5000 to 15000 rpm corresponds to angular velocities of 524 to 1571 rad/s.

At 5000 rpm, Rep = 0.02 x 1571 x 0.02 = 0.6284

At 15000 rpm, Rep = 0.02 x 524 x 0.02 = 0.2096

Using the correlation, we can calculate the convection coefficient for the given range of rotational speeds:

At 5000 rpm, Nap = 0.133 x (0.6284)^0.6 x (0.71)^0.4 = 10.9 W/(m²K)

At 15000 rpm, Nap = 0.133 x (0.2096)^0.6 x (0.71)^0.4 = 47.2 W/(m²K)

The maximum heat rate per unit length can be calculated using the following formula:

qmax = hmax × (Ts - Tinf)

where Ts is the maximum surface temperature (87°C), Tinf is the ambient air temperature (27°C), and hmax is the maximum convection coefficient obtained at the highest rotational speed (15000 rpm).

At 15000 rpm, qmax = 47.2 x (87 - 27) = 2.83 kW/m

(b) For a stationary shaft, the free convection correlation for a horizontal cylinder is:

Nuf = 0.60 + 0.387 (Gr Pr / (1 + (0.559 / Pr)^(9/16))^ (16/27))

where Gr = g beta (Ts - Tinf) D³ / nu², beta is the thermal expansion coefficient, nu is the kinematic viscosity, and g is the gravitational acceleration.

For air at 27°C, beta = 3.41e-3 K⁻¹, nu = 1.49e-5 m²/s, and D = 20 mm.

The Grashof number can be calculated using the maximum surface temperature:

Gr = 9.81 x 3.41e⁻³ x (87 - 27) x (0.02)³ / (1.49e-5)²= 1.71e+11

The Prandtl number is the same as before (0.71).

Using the correlation, we can calculate the free convection coefficient:

Nuf = 0.60 + 0.387 (1.71e+11 * 0.71 / (1 + (0.559 / 0.71)^(9/16))^ (16/27)) = 16.5 W/(m^2*K)

The maximum heat rate per unit length can be calculated using the same formula as before:

qmax = hmax × (Ts - Tinf)

where hmax is the free convection coefficient obtained above.

At stationary conditions, qmax = 16.5 x (87 - 27) = 1.65 kW/m

Mixed free and forced convection effects may become significant for Rep < 4.7(Gr/Pr). For the given range of rotational speeds, Rep < 4.7(Gr/Pr) holds true. Therefore, mixed convection effects may become significant.

(c) Radiation exchange is important since the emissivity of the shaft is given as 0.8, radiation exchange is important. The net radiation heat transfer rate between the shaft and the surroundings is given by the Stefan-Boltzmann law:

qrad = ε σ (Ts^4 - Tinf^4) A

where ε is the emissivity, σ is the Stefan-Boltzmann constant, Ts is the surface temperature of the shaft, Tinf is the ambient air temperature, and A is the surface area of the shaft.

Assuming a length of 1 m for the shaft, the surface area is:

A = π D L = π (0.02) (1) = 0.0628 m^2

Using the given values, we can calculate the radiation heat transfer rate:

qrad = 0.8 x 5.67e⁻⁸ x (87⁴ - 27⁴) x 0.0628 = 455 W/m

Therefore, radiation exchange can have a significant impact on the heat transfer from the shaft to the surroundings.

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The maximum heat rate per unit length and the convection coefficient as a function of rotational speed is 2.83 kW/m

The effects of mixed convection may become significant.

The exchange of radiation can have a significant impact on heat transfer from the shaft to the surroundings.

How to calculate convection coefficient and the maximum heat?

(a) For rotating cylinders, the correlation for estimating the convection coefficient is given by:

Nap = 0.133 Rep^0.6 Pr^0.4

where Rep = OD' and Pr is the Prandtl number. For air at 27°C, Pr = 0.71 and OD = 20 mm.

The rotational speed in the range from 5000 to 15000 rpm corresponds to angular velocities of 524 to 1571 rad/s.

At 5000 rpm, Rep = 0.02 x 1571 x 0.02 = 0.6284

At 15000 rpm, Rep = 0.02 x 524 x 0.02 = 0.2096

Using the correlation, we can calculate the convection coefficient for the given range of rotational speeds:

At 5000 rpm, Nap = 0.133 x (0.6284)^0.6 x (0.71)^0.4 = 10.9 W/(m²K)

At 15000 rpm, Nap = 0.133 x (0.2096)^0.6 x (0.71)^0.4 = 47.2 W/(m²K)

The maximum heat rate per unit length can be calculated using the following formula:

qmax = hmax × (Ts - Tinf)

where Ts is the maximum surface temperature (87°C), Tinf is the ambient air temperature (27°C), and hmax is the maximum convection coefficient obtained at the highest rotational speed (15000 rpm).

At 15000 rpm, qmax = 47.2 x (87 - 27) = 2.83 kW/m

(b) For a stationary shaft, the free convection correlation for a horizontal cylinder is:

Nuf = 0.60 + 0.387 (Gr Pr / (1 + (0.559 / Pr)^(9/16))^ (16/27))

where Gr = g beta (Ts - Tinf) D³ / nu², beta is the thermal expansion coefficient, nu is the kinematic viscosity, and g is the gravitational acceleration.

For air at 27°C, beta = 3.41e-3 K⁻¹, nu = 1.49e-5 m²/s, and D = 20 mm.

The Grashof number can be calculated using the maximum surface temperature:

Gr = 9.81 x 3.41e⁻³ x (87 - 27) x (0.02)³ / (1.49e-5)²= 1.71e+11

The Prandtl number is the same as before (0.71).

Using the correlation, we can calculate the free convection coefficient:

Nuf = 0.60 + 0.387 (1.71e+11 * 0.71 / (1 + (0.559 / 0.71)^(9/16))^ (16/27)) = 16.5 W/(m^2*K)

The maximum heat rate per unit length can be calculated using the same formula as before:

qmax = hmax × (Ts - Tinf)

where hmax is the free convection coefficient obtained above.

At stationary conditions, qmax = 16.5 x (87 - 27) = 1.65 kW/m

Mixed free and forced convection effects may become significant for Rep < 4.7(Gr/Pr). For the given range of rotational speeds, Rep < 4.7(Gr/Pr) holds true. Therefore, mixed convection effects may become significant.

(c) Radiation exchange is important since the emissivity of the shaft is given as 0.8, radiation exchange is important. The net radiation heat transfer rate between the shaft and the surroundings is given by the Stefan-Boltzmann law:

qrad = ε σ (Ts^4 - Tinf^4) A

where ε is the emissivity, σ is the Stefan-Boltzmann constant, Ts is the surface temperature of the shaft, Tinf is the ambient air temperature, and A is the surface area of the shaft.

Assuming a length of 1 m for the shaft, the surface area is:

A = π D L = π (0.02) (1) = 0.0628 m^2

Using the given values, we can calculate the radiation heat transfer rate:

qrad = 0.8 x 5.67e⁻⁸ x (87⁴ - 27⁴) x 0.0628 = 455 W/m

Therefore, radiation exchange can have a significant impact on the heat transfer from the shaft to the surroundings.

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In seismic areas, the most crucial requirement for precast concrete is:
1) not to build higher than two stories.
2) to tie elements together laterally.
3) to make ductile concrete beams.
O 4) to use only steel columns.
5)
precast concrete cannot be used in seismic zones.

Answers

Answer:

Option 2, In seismic areas, the most crucial requirement for precast concrete is to tie elements together laterally

Explanation:

In seismic areas, the in-plane lateral  forces are very larger and hence in order to restrict the lateral movement governed by the lateral force, lateral ties are essential .

Specific design detailing such as interior and  perimeter ties in the floors causes diaphragm behavior and hence distribute the load evenly without any movement.

Hence, option 2 is correct

how many rotations of the crankshaft are required to complete each stroke of a four-stroke cycle engine?

Answers

answer!!


two revolutions



An operating cycle requires two revolutions (720°) of the crankshaft. The four-stroke cycle engine is the most common type of small engine.


hope this helps kiddo!
TWO REVOLUTIONS

Therefore, a four-stroke cycle requires two revolutions of the crankshaft.

Suppose that you have the following declaration.
enum cars {FORD, GM, TOYOTA, HONDA};
cars domesticCars = FORD;
The statement:
domesticCars = static_cast(domesticCars + 1);
sets the value of domestiCars to _________.

Answers

[answer removed by author]

In the given example, which type of interior designer is Sarah? Sarah is an interior designer. The state in which she resides applies practice acts to interior design professionals. Therefore, Sarah carries the title of a ____ interior designer.

Answers

Answer:

Sarah is a professional interior designer.

Therefore, Sarah carries the title of a _registered___ interior designer.

Explanation:

Some states require only the licensed designers to carry out interior designs, while some others allow both the licensed and unlicensed interior designers to carry on the work of interior designers.  In the states where only the licensed designers are allowed to use the title of interior designer, they are registered after passing the state-prescribed examinations and meeting some professional experience requirements. The most common exam is the National Council for Interior Design Qualification (NCIDQ) examination, which only bachelor degree holders in interior design are allowed to sit for.

If you move and change your address, the mvc must be notified no later than ____ after moving.

Answers

As per the law, if you move and change your address, you must notify the MVC no later than one week (7 days) after moving. This notification is essential as it helps to update the agency's database to ensure that you receive all the necessary notifications regarding your driving privileges and registration.

Moving to a new state requires a change in the state of residence and therefore a change of the license plate. The same also applies if you move within the state. For instance, if you move from Essex County to Hudson County, the MVC needs to be notified so that they can update their database and issue a new license plate that reflects your current address.Changing your address with the MVC can be done through their online portal or in-person at the nearest MVC office. You will need to fill out the appropriate forms, provide proof of your new address, and pay any necessary fees. It is important to note that failure to notify the MVC of a change of address can result in penalties or fines.

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After cutting a PVC pipe you should use a
to debure the pipe

Answers

Answer:

Deburring Tool

Explanation:

A deburring tool is used in order to debur the PVC pipes. They are mostly used for the plastic pipes.

After the PVC pipes are cut, there are burrs on the pipe surface. To remove these burrs, a deburring tool is used. It removes the burrs form the edges of the PVC pipes that results from grinding, cutting, milling, drilling, etc.

The deburring tools are made from high speed steels.

Non-motorized vehicles are allowed on expressways.True or False

Answers

Non-motorized vehicles are allowed on expressways.The statement is false.

What is vehicles?

Vehicles are machines used to transport people and goods from one place to another. They come in all shapes and sizes, from cars, buses, and trucks, to boats, planes, and even spacecraft. Vehicles have been around for centuries, and have been used for everything from military operations to leisurely travel.

Non-motorized vehicles such as bicycles and skateboards are not allowed on expressways due to safety concerns. The speed of expressway traffic and the lack of physical barriers between vehicles and the roadway make it too dangerous for non-motorized vehicles.

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What is the best way to collaborate with your team when publishing Instagram Stories from Hootsuite?

Answers

Implement a robust approval process with multiple touch points so every team member has input
Save the Story as a draft, then share it with your team via Hootsuite Inbox to gather feedback before publishing
Schedule Stories in the Planner so they can be reviewed and edited by the approver directly
Add specific publishing notes in the composer to help guide the teammate ultimately publishing the Stories
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