Discuss typical advantages and disadvantages of an irrigation system?
4 An approach to a pretimed signal has 30 seconds of effective red, and D/D/1 queuing holds. The total delay at the approach is 83.33 veh-s/cycle and the saturation flow rate is 1000 veh/h. If the capacity of the approach equals the number of arrivals per cycle, determine the approach flow rate and cycle length.
Answer:
Following are the responses to the given question:
Explanation:
Effective red duration is applied each cycle r=30 second D/D/1 queuing
In total, its approach delay is 83.33 sec vehicle per cycle
Flow rate(s) of saturated = 1,000 vehicles each hour
Total vehicle delay per cycle[tex]= \frac{v \times 30^2}{2(1-\frac{v}{0.2778})}[/tex]
[tex]\to \frac{v\times 30^2}{2(1-\frac{v}{0.2778})}= 83.33\\\\\to 900v=166.66-599.928v\\\\\to v=0.111 \frac{veh}{sec}\\\\[/tex]
The flow rate for such total approach is 0.111 per second.
The overall flow velocity of the approach is 400 cars per hour
The approach capacity refers to the number of arrivals per cycle.
Environmentally friendly time ratio to cycle length:
[tex],\frac{g}{C} \ is = \frac{400}{1000}=0.4\\\\r= c-g\\\\30\ sec =C - 0.4 C\\\\C=50 \ sec[/tex]
A cylinder is internally pressurized to a pressure of 100 MPa. This causes tangential and axial stresses in the outer surface of 400 and 200 MPa, respectively. Make a Mohr circle representation of the stresses in the outer surface. What maximum normal and shear stresses are experienced by the outer surface?
Answer:
[tex]\mu_{max}=200Mpa[/tex]
Explanation:
From the question we are told that:
Internally pressurized [tex]P_i=100MPa[/tex]
Tangential Stress [tex]P_t=400mpa[/tex]
Axial stress [tex]P_a=200mpa[/tex]
Generally the equation for maximum normal and shear stresses are experienced by the outer surface is mathematically given by
[tex]\mu_{max}=|\frac{P_t-P_a}{2}|,|\frac{P_t}{2}|,|\frac{P_t}{2}|[/tex]
Therefore
[tex]\mu_{max}=|\frac{400-200}{2}|,|\frac{400}{2}|,|\frac{200}{2}|[/tex]
[tex]\mu_{max}=200Mpa[/tex]
In a tension test of steel, the ultimate load was 13,100 lb and the elongation was 0.52 in. The original diameter of the specimen was 0.50 in. and the gage length was 2.00 in. Calculate (a) the ultimate tensile stress (b) the ductility of the material in terms of percent elongation
Answer:
a) the ultimate tensile stress is 66717.8 psi
b) the ductility of the material in terms of percent elongation is 26%
Explanation:
Given the data in the question;
ultimate load P = 13,100 lb
elongation δl = 0.52 in
diameter of specimen d = 0.50 in
gage length l = 2.00 inch
First we determine the cross-sectional area of the specimen
A = [tex]\frac{\pi }{4}[/tex] × d²
we substitute
A = [tex]\frac{\pi }{4}[/tex] × ( 0.50 )²
A = 0.1963495 in²
a) the ultimate tensile stress σ[tex]_u[/tex]
tensile stress σ[tex]_u[/tex] = P / A
we substitute
tensile stress σ[tex]_u[/tex] = 13,100 / 0.1963495
tensile stress σ[tex]_u[/tex] = 66717.766 ≈ 66717.8 psi
Therefore, the ultimate tensile stress is 66717.8 psi
b) ductility of the material in terms of percent elongation;
percentage elongation of specimen = [change in length / original length]100
% = [ δl / l ]100
we substitute
% = [ 0.52 in / 2.00 in ]100
= [ 0.26 ]100
= 26
Therefore, the ductility of the material in terms of percent elongation is 26%
Consider a single crystal of silver oriented such that tensile stress is applied along a (0 0 1) direction. If slip occurs on a (1 1 1) plane and in a (1 0 1) direction and is initiated at an applied tensile stress of 1.1 MPa (160 psi), compute the critical resolved shear stress.
Answer:
i don't know
Explanation:
sorry
Unit of rate of heat transfer
Answer:
The units on the rate of heat transfer are Joule/second, also known as a Watt.
Explanation:
Heat flow is calculated using the rock thermal conductivity multiplied by the temperature gradient. The standard units are mW/m2 = milli Watts per meter squared. Thus, think of a flat plane 1 meter by 1 meter and how much energy is transferred through that plane is the amount of heat flow.
hope it helps .
stay safe healthy and happy..The rate of heat transfer is measured in Joules per second, also known as Watts.
What is heat transfer?Heat transfer is a thermal engineering discipline that deals with the generation, use, conversion, and exchange of thermal energy between physical systems.
Heat transfer mechanisms include thermal conduction, thermal convection, thermal radiation, and energy transfer via phase changes.
The rate of heat transfer through a unit thickness of material per unit area per unit temperature difference is defined as thermal conductivity. Thermal conductivity varies with temperature and is measured experimentally.
Heat is typically transferred in a combination of these three types and occurs at random. Heat transfer rate is measured in Joules per second, also known as Watts.
Thus, Joules per second or watts is the unit of rate of heat transfer.
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The term variation describes the degree to which an object or idea differs from others of the same type or from a standard.
a. True
b. False
Air at 40C flows over a 2 m long flat plate with a free stream velocity of 7 m/s. Assume the width of the plate (into the paper) is 0.5 m. If the plate is at a constant temperature of 100C, find:
Complete Question
Air at 40C flows over a 2 m long flat plate with a free stream velocity of 7m/s. Assume the width of the plate (into the paper) is 0.5 m. If the plate is at a co temperature of 100C,find:
The total heat transfer rate from the plate to the air
Answer:
[tex]q=1.7845[/tex]
Explanation:
From the question we are told that:
Air Temperature [tex]T_1=40c[/tex]
Length [tex]l=2m[/tex]
Velocity [tex]v=7m/s[/tex]
Width [tex]w=0.5[/tex]
Constant temperature [tex]T_t= 100C[/tex]
Generally the equation for Total heat Transfer is mathematically given by
[tex]q=hA(T_s-T_\infty)[/tex]
Where
h=Convective heat transfer coefficient
[tex]h=29.9075w/m^2k[/tex]
Therefore
[tex]q=h(L*B)(T_s-T_\infty)[/tex]
[tex]q=29.9075*(2*0.5)(100+273-(40+273))[/tex]
[tex]q=1794.45w[/tex]
[tex]q=1.7845[/tex]
Complete the following two statements regarding quantum-mechanical concepts associated with the Bohr model of the atom and refinements that resulted from the wave- mechanical atomic model.
Two important quantum-mechanical concepts associated with the Bohr model of the atom are that eledtrons are particles moving in _________ electron energy is quantized into
(b) Two important refinements resulting from the wave-mechanical atomic model are that the electron position is described in terms of a ______ electron energy is quantized into both shells and subshells--each electron is characterized by ________, and ______ , and quantum numbers.
an amplifier has an input resistance of 100k a short-circuit transconductance of 10 mA/V and an output resistance of 100k. Find the open-circuit voltage gain
Answer:
The open circuit voltage gain is [tex]A_{vo}=-10^{3}[/tex]
Explanation:
Given data is input resistance of an amplifier is [tex]R_{in}=100k[/tex]Ω and output resistance of an amplifier is [tex]R_{o} =100k[/tex]Ω.
Trans conductance of an amplifier is [tex]g_{m}=10mA/V[/tex]
Thus Open circuit voltage gain is
[tex]A_{vo} =-g_{m}R_{o}[/tex]
[tex]A_{vo}=-10[/tex]×[tex]10^{-3}[/tex]×100×[tex]10^{3}[/tex]
Since 1m=[tex]10^{-3}[/tex] and 1k=[tex]10^{3}[/tex]
Thus,
[tex]A_{vo}=-1000[/tex]
[tex]A_{vo}=-10^{3}[/tex]
tech a says that a slightly lean mixture offers good fuel economy and low exhaust emissions. Tech b says that a mixture that is too rich fouls spark plugs and causes incomplete burning. Who is correct
If the same type of thermoplastic polymer is being tensile tested and the strain rate is increased, it will: g
Answer:
It would break I think need to try it out
Explanation:
Which of the following are major components of a Class II BSC: A. Cabinet blower switch B. Foot support C. Drain spillage trough (catch basin) D. Rear grille E. Temperature control
Answer:
Cabinet blower switch ( A )
Explanation:
A major component of a class II BSC ( Biological safety cabinet ) is Cabinet blower switch because the Cabinet blower is an integral part of a class II BSC hence the switch is also a major component.
Class II BSC provides protection for the user, environment and sample to be manipulated in the laboratory ( mostly ; Pharmaceutical laboratories, Microbiology laboratories )
How do Machine Learning and Artificial Intelligence (AI) technologies help businesses use their enterprise data effectively?
Answer:
Explanation:
Application of artificial intelligence in business
You can use AI technologies to:
Improve customer services - eg use virtual assistant programs to provide real-time support to users (for example, with billing and other tasks).
Automate workloads - eg collect and analyse data from smart sensors, or use machine learning (ML) algorithms to categorise work, automatically route service requests, etc.
Optimise logistics - eg use AI-powered image recognition tools to monitor and optimise your infrastructure, plan transport routes, etc.
Increase manufacturing output and efficiency - eg automate production line by integrating industrial robots into your workflow and teaching them to perform labour-intensive or mundane tasks.
Prevent outages - eg use anomaly detection techniques to identify patterns that are likely to disrupt your business, such as an IT outage. Specific AI software may also help you to detect and deter security intrusions.
Predict performance - eg use AI applications to determine when you might reach performance goals, such as response time to help desk calls.
Predict behaviour - eg use ML algorithms to analyse patterns of online behaviour to, for example, serve tailored product offers, detect credit card fraud or target appropriate adverts.
Manage and analyse your data - eg AI can help you interpret and mine your data more efficiently than ever before and provide meaningful insight into your assets, your brand, staff or customers.
Improve your marketing and advertising - for example, effectively track user behaviour and automate many routine marketing tasks.
Machine learning is an Artificial intelligence-powered system that is based on a similar concept and able to learn from the intelligence provided by humans.
The AI systems are used to perform complex tasks in a way that is similar to humans but with precision. The AI-enabled machinery learning can boost sales and enhance the marketing campaign of any business or organization. It can develop a faster road map.Learn more about Machine Learning and Artificial Intelligence (AI) technologies.
brainly.in/question/32566751.
A frost free, 17 cu. ft. refrigerator-freezer uses energy at a rate of 500. watts when you hear the compressor running. If the fridge runs for 200. hours per month, how many kilowatt-hours of energy does the refrigerator use each month
Answer:
100 kWh
Explanation:
Since the freezer has a rating of 500 watts and runs for 200 hours in a month, the energy consumption can be gotten by getting the product of the rating of the freezer in kilowatts and the amount of time the fridge is on per month.
The rating of the freezer = 500 watts = 0.5 kW, time = 200 h
Energy consumption = rating * time = 0.5 kW * 200 h
Energy consumption = 100 kWh
Therefore the refrigerator uses 100 kWh per month
Assuming you determine the required section modulus of a wide flange beam is 200 in3, determine the lightest beam possible that will satisfy this condition.
Answer:
W18 * 106
Explanation:
Given that the section modulus of the wide flange beam is 200 in^3 the lightest beam possible that can satisfy the section modulus must have a section modulus ≥ 200 in^3. also the value of the section modulus must be approximately closest to 200in^3
From wide flange Beam table ( showing the section modulus )
The beam that can satisfy the condition is W18 × 106 because its section modulus ( s ) = 204 in^3
Find the equation of the output voltage as a function of time assuming the switch closes at t = 0 and the capacitor is fully discharged for t < 0.
Answer: Hello your question is incomplete attached below is the complete question
answer : V(out) (t) = 1 - e^-100t
Explanation:
The equation of the output voltage as a function of time assuming at t = 0 switch closes and capacitor will be discharged when t < 0
V(out) (t) = 1 - e^-100t
attached below is the step by step explanation
What happens to resistance in the strain gauge and voltage drop from a connected Wheatstone bridge if you were to pull the strain gauge along the long axis
Answer:
Resistance and voltage drop will still continue to rise, although at a slower pace than on the desired axis.
Explanation:
Pulling the strain gauge in the long axis causes the wires to elongate/thin, the effect of this is that it will lead to an increase in resistance and voltage drop (V = I*R).
As a result of the resultant effect, resistance and voltage drop will still continue to rise, although at a slower pace than on the desired axis, such as the long axis.
1. Using the formula above, complete this task.
Concrete is currently sold in increments of 12 yd'. Concrete current cost is $45 per V2 yd. How much would it cost a Shameka's Construction Company to cement a pad size 18ft x 20 ft. floor, 4 inches thick?
Answer:
gfbhjdskmlgtg
Explanation:
grtwhjyeywhtagsfdd
An air-standard Diesel cycle engine operates as follows: The temperatures at the beginning and end of the compression stroke are 30 °C and 700 °C, respectively. The net work per cycle is 590.1 kJ/kg, and the heat transfer input per cycle is 925 kJ/kg. Determine the a) compression ratio, b) maximum temperature of the cycle, and c) the cutoff ratio, v3/v2.
This question is incomplete, the complete question is;
An air-standard Diesel cycle engine operates as follows: The temperatures at the beginning and end of the compression stroke are 30 °C and 700 °C, respectively. The net work per cycle is 590.1 kJ/kg, and the heat transfer input per cycle is 925 kJ/kg. Determine the a) compression ratio, b) maximum temperature of the cycle, and c) the cutoff ratio, v3/v2.
Use the cold air standard assumptions.
Answer:
a) The compression ratio is 18.48
b) The maximum temperature of the cycle is 1893.4 K
c) The cutoff ratio, v₃/v₂ is 1.946
Explanation:
Given the data in the question;
Temperature at the start of a compression T₁ = 30°C = (30 + 273) = 303 K
Temperature at the end of a compression T₂ = 700°C = (700 + 273) = 973 K
Net work per cycle [tex]W_{net[/tex] = 590.1 kJ/kg
Heat transfer input per cycle Qs = 925 kJ/kg
a) compression ratio;
As illustrated in the diagram below, 1 - 2 is adiabatic compression;
so,
Tγ[tex]^{Y-1[/tex] = constant { For Air, γ = 1.4 }
hence;
⇒ V₁ / V₂ = [tex]([/tex] T₂ / T₁ [tex])^{\frac{1}{Y-1}[/tex]
so we substitute
⇒ V₁ / V₂ = [tex]([/tex] 973 K / 303 K [tex])^{\frac{1}{1.4-1}[/tex]
= [tex]([/tex] 3.21122 [tex])^{\frac{1}{0.4}[/tex]
= 18.4788 ≈ 18.48
Therefore, The compression ratio is 18.48
b) maximum temperature of the cycle
We know that for Air, Cp = 1.005 kJ/kgK
Now,
Heat transfer input per cycle Qs = Cp( T₃ - T₂ )
we substitute
925 = 1.005( T₃ - 700 )
( T₃ - 700 ) = 925 / 1.005
( T₃ - 700 ) = 920.398
T₃ = 920.398 + 700
T₃ = 1620.398 °C
T₃ = ( 1620.398 + 273 ) K
T₃ = 1893.396 K ≈ 1893.4 K
Therefore, The maximum temperature of the cycle is 1893.4 K
c) the cutoff ratio, v₃/v₂;
Since pressure is constant, V ∝ T
So,
cutoff ratio S = v₃ / v₂ = T₃ / T₂
we substitute
cutoff ratio S = 1893.396 K / 973 K
cutoff ratio S = 1.9459 ≈ 1.946
Therefore, the cutoff ratio, v₃/v₂ is 1.946
Problem 1. Network-Flow Programming (25pt) A given merchandise must be transported at a minimum total cost between two origins (supply) and two destinations (demand). Destination 1 and 2 demand 500 and 700 units of merchandise, respectively. At the origins, the available amounts of merchandise are 600 and 800 units. USPS charges $5 per unit from origin 1 to demand 1, and $7 per unit from origin 1 to demand 2. From origin 2 to demand 1 and 2, USPS charges the same unit cost, $10 per unit, however, after 200 units, the unit cost of transportation increases by 50% (only from origin 2 to demand 1 and 2).
a) Formulate this as a network-flow problem in terms of objective function and constraint(s) and solve using Excel Solver.
b) How many units of merchandise should be shipped on each route and what is total cost?
Solution :
Cost
Destination Destination Destination Maximum supply
Origin 1 5 7 600
Origin 2 10 10 800
15, for > 200 15, for > 200
Demand 500 700
Variables
Destination 1 2
Origin 1 [tex]$X_1$[/tex] [tex]$$X_2[/tex]
Origin 2 [tex]$X_3$[/tex] [tex]$$X_4[/tex]
Constraints : [tex]$X_1$[/tex], [tex]$$X_2[/tex], [tex]$X_3$[/tex], [tex]$$X_4[/tex] ≥ 0
Supply : [tex]$X_1$[/tex] + [tex]$$X_2[/tex] ≤ 600
[tex]$X_3$[/tex] + [tex]$$X_4[/tex] ≤ 800
Demand : [tex]$X_1$[/tex] + [tex]$$X_3[/tex] ≥ 500
[tex]$X_2$[/tex] + [tex]$$X_4[/tex] ≥ 700
Objective function :
Min z = [tex]$5X_1+7X_2+10X_3+10X_4, \ (if \ X_3, X_4 \leq 200)$[/tex]
[tex]$=5X_1+7X_2+(10\times 200)+(X_3-200)15+(10 \times 200)+(X_4-200 )\times 15 , \ \ (\text{else})$[/tex]
Costs :
Destination 1 Destination 2
Origin 1 5 7
Origin 2 10 10
15 15
Variables :
[tex]$X_1$[/tex] [tex]$$X_2[/tex]
300 300
200 400
[tex]$X_3$[/tex] [tex]$$X_4[/tex]
Objective function : Min z = 10600
Constraints:
Supply 600 ≤ 600
600 ≤ 800
Demand 500 ≥ 500
700 ≥ 500
Therefore, the total cost is 10,600.
what is Geography? pliz help
Answer:
hope it's helpful please like and Follow me
Answer:
Geography is the science that studies and describes the surface of the Earth in its physical, current and natural aspect, or as a place inhabited by humanity.
True or false all workers who do class 1 asbestos work must be part of a medical surveillance program
Answer:
Yes
Explanation:
Answer:
true
Explanation:
hehehe
1. A hydro facility operates with an elevation difference of 50 m and a flow rate of 500 m3/s. If the rotational speed is 90 RPM, find the most suitable type of turbine and estimate the power output of the arrangement
Answer:
a) Pelton Turbine
b) [tex]P=2.42*10^{5}KW[/tex]
Explanation:
From the question we are told that:
Height [tex]h=50[/tex]
Flow Rate [tex]R= 500 m^3/s[/tex]
Rotational speed [tex]\omega=\90 RPM[/tex]
Let
Density of water
[tex]\rho=1000[/tex]
Generally the equation for momentum is mathematically given by
[tex]P=\rho gRh[/tex]
[tex]P=1000*9.81*500*50[/tex]
[tex]P=2.42*10^{5}KW[/tex]
Which option identifies the best way to reduce the environmental impact in the following scenario?
Sheryl has been assessing a factory where cheese is made and packaged. She has determined that the
product's packaging is the component that causes the highest environmental impact.
Sheryl should implement steps to create a cheese that does not need to be packaged.
0 Sheryl should implement steps to educate the factory personnel on the subject of conservation.
O Sheryl should implement steps to optimize the packaging in an eco-friendly manner.
O Sheryl should implement steps to reduce costs in the packaging department.
Sheryl should implement steps to optimize the packaging in an eco-friendly manner.
What would the Select lines need to be to send data for the fifth bit in an 8-bit system (S0 being the MSB and S2 being the LSB)?
A. S0 = 1, S1 = 0, S2 = 0
B. S0 = 0, S1 = 0, S2 = 0
C. S0 = 0, S1 = 1, S2 = 0
D. S0 = 0, S1 = 1, S2 = 1
Answer:
A. S0 = 1, S1 = 0, S2 = 0
lines need to send data for the fifth bit in an 8 bit system
A rapid sand filter has a loading rate of 8.00 m/h, surface dimensions of , an effective filtration rate of 7.70 m/h, and a production efficiency of 96 percent. A complete filter cycle duration is 52 h and the filter is rinsed for 20 minutes at the start of each cycle
Required:
a. What flow rate (m3/s) does the filter handle during production?
b. What volume of water is needed for backwashing plus rinsing the filter in each filter cycle?
Answer: hello there is a Missing information below is the missing information
surface dimensions of 10m * 8m
answer :
a) 640 m^3/hr
b) 1334.66 m^3
Explanation:
a) Determine the flow rate ( m^3/s ) of the filter handle
Va = Q /A[tex]_{f}[/tex]
where ; Va = filtration rate ( 8.00 m/h ) , Q = flow rate of filter handle , A[tex]_{f}[/tex] = surface area ( 10 m * 8 m )
Q = 8 * ( 10m * 8m ) = 640 m^3 / hr
b) Determine the volume of water needed for backwashing plus rinsing the filter in each filter cycle
Лf = 0.96 ( production efficiency )
Vb + Vr = 0.04 Vf
∴ Vf = ( Vb + Vr ) / 0.04 ------ ( 1 )
next step ; determine the volume of filtered water making use of effective filtration rate
Ref = ( Vf - Vb - Vr ) / A[tex]_{f}[/tex]T[tex]_{c}[/tex]
therefore : Vb + Vr = Vf - ( 80 * 52 * 7.7 ) ---- ( 2 )
Input equation 1 into 2
Vb + Vr = ( ( Vb + Vr ) / 0.04 ) - 32032 ---- ( 3 )
Resolve equation 3
hence the Volume of water needed for Backwashing and rinsing the filter in each filter cycle
= 1334.66 m^3
6.D1 A large tower is to be supported by a series of steel wires. It is estimated that the load on each wire will be 13,300 N (3000 lbf). Determine the minimum required wire diameter assuming a factor of safety of 2 and a yield strength of 860 MPa (125,000 psi).
Answer:
6.33 mm
Explanation:
Stress is an internally resistive force produced by the molecules of the object to resist the deformation when an amount of load acts on the object. The SI unit of stress is measured in Pascal.
Given that force (F) = 13300 N, factor of safety (λ) = 2, yield strength (σy) = 860 MPa
The working stress [tex](\sigma_w)=\frac{\sigma_y}{\lambda}=\frac{860\ MPa}{2}=430\ MPa[/tex]
Let d be the minimum diameter, hence it is calculated using:
[tex]\sigma_w=\frac{F}{A}\\\\430 *10^6=\frac{13300}{A}\\\\A=30.93*10^{-6}\ m^2\\\\A=area=\frac{\pi d^2}{4} \\\\30.93*10^{-6}\ m^2=\frac{\pi d^2}{4} \\\\d=\sqrt{\frac{4*30.93*10^{-6}}{\pi } } \\\\d=0.0063\ m=6.3\ mm[/tex]
In how many ways 2450 can be written as a product of 2 factors?
Select one:
O a. 9
O b. 6
C. 18
O d. 10
Answer:
search up factors of 2450 and divide by two
The number of ways 2450 can be written as a product of 2 factors is 9 ways
How to find factors of numbers?Factors of 2,450 = 1, 2, 5, 7, 10, 14, 25, 35, 49, 50, 70, 98, 175, 245, 350, 490, 1225, 2450
2450 has 18 factors.The number of ways 2450 can be written as a product of 2 factors = number of factors / 2
= 18/2
= 9 wats
This means, taking the product of two factors such as;
1 × 2450
2 × 1225
5 × 490
7 × 350
10 × 245
14 × 175
25 × 98
35 × 70
50 × 98
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The roof of a house has three layers: (1) 2 inch thick pine, (2) 4 inches of fiberglass insulation and (3) 0.1 inch thick Asphalt shingles. Calculate the rate of flow of heat (BTU/hour) through the roof. The temperature inside the house is 700F and the temperature outside is 300F. The R/inch for pine is 1.28, the R/inch for fiberglass is 3.0 and the R/inch for Shingles is 4.0. Take the area of the roof to be 500 square feet. The Unit of R is mixed: ft2 . 0F.h/BTU
Answer:
the rate of flow of heat through the roof is 45616.858 BTU/hr
Explanation:
Given the data in the question;
pin thickness [tex]t_p[/tex] = 2 in
fiber glass thickness [tex]t_f[/tex] = 4 in
Asphalt shingles thickness [tex]t_a[/tex] = 0.1 in
R/inch for pine = 1.28
R/inch for fiberglass = 3.0
R/inch for Shingles = 4.0
Temperature inside the house [tex]T_{inside[/tex] = 700 F
Temperature outside the house [tex]T_{outside[/tex] = 300 F
area of the roof A = 500 ft²
we calculate the total Resistance;
R = ( 2 × 1.28 ) + ( 4 × 3.0 ) + ( 0.1 × 4.0 )
R = 2.56 + 12 + 0.4
R = 14.96
Now, we determine the rate of heat flow;
dQ/dt = ΔT(A) / R
⇒ ( [tex]T_{inside[/tex] - [tex]T_{outside[/tex] )A / R
we substitute
⇒ (( 700 - 300 ) × 500 ) / 14.96
⇒ ( 400 × 500 ) / 14.96
⇒ 200000 / 14.96
⇒ 13368.98 watt
we know that 1 watt = 3.412142 BTU/hr
⇒ ( 13368.98 × 3.412142 ) BTU/hr
⇒ 45616.858 BTU/hr
Therefore, the rate of flow of heat through the roof is 45616.858 BTU/hr