The statement that is correct about the relation between the velocity boundary layer and heat transfer for flow over a flat plate that is uniform in temperature is
Answer: the heat flux increases as the velocity boundary layer transitions to laminar to turbulent.
Explanation:
The correct statement about the relation between the velocity boundary layer and heat transfer for flow over a flat plate that is uniform in temperature is that the heat flux increases as the velocity boundary layer transitions to laminar to turbulent.
It should be noted that the heat goes in a streamline direction in a laminar flow, thereby the molecules less collide with each other. On the other hand, the direction is zig zag in a turbulent heat flux and this will bring about more collision of the molecules which leads to a rise in the heat flux.
Reynolds Number.Typical values of the Reynolds number for various animalsmoving through air or water are listed below. For which cases is inertia of the fluid important? For which cases do viscous effects dominate? For which cases would the flow be laminar; turbulent? Explain.
Animal Speed Re
(a) large whale 10m/s 300,000,000
(b) tlying duck 20m/s 300,000
(c) large dragonfly 7m/s 30,000
(d) invertebrate larva 1mm/s 0.3
(e) bacterium 0.01mm/s 0.00003
Answer:
i) Cases with Important Inertia
Large whale ( a ) , Flying duck ( b ) , Large dragonfly ( c )
ii) Cases where viscous effects dominate
Invertebrate larva ( d ) , bacterium ( e )
iii) Cases where flow is Laminar ( cases where Re is < 2,100 )
Invertebrate larva ( d ), bacterium ( e )
iv) Cases where flow is turbulent ( case Re is > 2,100 )
Large whale (a) , Flying duck (b), Large dragonfly ( c ),
Explanation:
Reynolds number is the the ratio of Initial forces to viscous forces, hence cases with Large Reynolds number ( > 2100 ) have their inertial forces greater than viscous forces, therefore we can say the Inertia is more important , while cases with smaller Reynolds number ( < 2100 ) have the viscous forces greater than the inertial forces therefore in such case the viscous effect is more important
i) Cases with Important Inertia
Large whale ( a ) , Flying duck ( b ) , Large dragonfly ( c )
ii) Cases where viscous effects dominate
Invertebrate larva ( d ) , bacterium ( e )
iii) Cases where flow is Laminar ( cases where Re is < 2,100 )
Invertebrate larva ( d ), bacterium ( e )
iv) Cases where flow is turbulent ( case Re is > 2,100 )
Large whale (a) , Flying duck (b), Large dragonfly ( c ),
Given below are the measured streamflows in cfs from a storm of 6-hour duration on a stream having a drainage area of 185 mi^2. Derive the unit hydrograph by the inverse procedure. Assume a constant baseflow of 550 cfs.
Hour Day 1 Day 2 Day 3 Day 4
Midnight 550 5,000 19,000 550
6 am 600 4,000 1400
Noon 9000 3000 1000
6 pm 6600 2500 750
Answer:
33.56 ft^3/sec.in
Explanation:
Duration = 6 hours
drainage area = 185 mi^2
constant baseflow = 550 cfs
Derive the unit hydrograph using the inverse procedure
first step : calculate for the volume of direct runoff hydrograph using the details in table 2 attached below
Vdrh = sum of drh * duration
= 29700 * 6 hours ( 216000 secs )
= 641,520,000 ft^3.
next step : Calculate the volume of runoff in equivalent depth
Vdrh / Area = 641,520,000 / 185 mi^2
= 1.49 in
Finally derive the unit hydrograph
Unit of hydrograph = drh / volume of runoff in equivalent depth
= 50 ft^3 / 1.49 in = 33.56 ft^3/sec.in
Water flows through a converging pipe at a mass flow rate of 25 kg/s. If the inside diameter of the pipes sections are 7.0 cm and 5.0 cm, find the volume flow rate and the average velocity in each pipe section.
Answer:
volumetric flow rate = [tex]0.0251 m^3/s[/tex]
Velocity in pipe section 1 = [tex]6.513m/s[/tex]
velocity in pipe section 2 = 12.79 m/s
Explanation:
We can obtain the volume flow rate from the mass flow rate by utilizing the fact that the fluid has the same density when measuring the mass flow rate and the volumetric flow rates.
The density of water is = 997 kg/m³
density = mass/ volume
since we are given the mass, therefore, the volume will be mass/density
25/997 = [tex]0.0251 m^3/s[/tex]
volumetric flow rate = [tex]0.0251 m^3/s[/tex]
Average velocity calculations:
Pipe section A:
cross-sectional area =
[tex]\pi \times d^2\\=\pi \times 0.07^2 = 3.85\times10^{-3}m^2[/tex]
mass flow rate = density X cross-sectional area X velocity
velocity = mass flow rate /(density X cross-sectional area)
[tex]velocity = 25/(997 \times 3.85\times10^{-3}) = 6.513m/s[/tex]
Pipe section B:
cross-sectional area =
[tex]\pi \times d^2\\=\pi \times 0.05^2= 1.96\times10^{-3}m^2[/tex]
mass flow rate = density X cross-sectional area X velocity
velocity = mass flow rate /(density X cross-sectional area)
[tex]velocity = 25/(997 \times 1.96\times10^{-3}) = 12.79m/s[/tex]
A brittle material is subjected to a tensile stress of 1.65 MPa. If the specific surface energy and modulus of elasticity for this material are 0.60 J/m2 and 2.0 GPa, respectively. What is the maximum length of a surface flaw that is possible without fracture
Answer:
The maximum length of a surface flaw that is possible without fracture is
[tex]2.806 \times 10^{-4} m[/tex]
Explanation:
The given values are,
σ=1.65 MPa
γs=0.60 J/m2
E= 2.0 GPa
The maximum possible length is calculated as:
[tex]\begin{gathered}a=\frac{2 E \gamma_{s}}{\pi \sigma^{2}}=\frac{(2)\left(2 \times 10^{9} \mathrm{~N} / \mathrm{m}^{2}\right)(0.60 \mathrm{~N} / \mathrm{m})}{\pi\left(1.65\times 10^{6} \mathrm{~N} / \mathrm{m}^{2}\right)^{2}} \\=2.806 \times 10^{-4} \mathrm{~m}\end{gathered}[/tex]
The maximum length of a surface flaw that is possible without fracture is
[tex]2.806 \times 10^{-4} m[/tex]
Question
А
Particle of 2kg mass is being pulled across a smooth horizontal
surface by a horizontal force. The force does 24 Joule of work in
increasing
the particle's
velocity from 5m/s
to v m/s. calculate
the value of v and the position of particle
after 15s
Answer:
udhddhdiejebdidjebdhdidh
Convert the following indoor air quality standards, established by the U.S. Occupational Safety and Health Administration (OSHA), from ppmv to mg/m3 (at 25°C and 1atm) or vice versa.
a. Carbon dioxide (CO2), 5,000 ppmv
b. Formaldehyde (HCHO), 3.6 mg/m^3
c. Nitric oxide (NO), 25 ppmv
Calculate the biaxial stresses σ1 and σ2 for the biaxial stress case, where ε1 = .0020 and ε2 = –.0010 are determined experimentally on an aluminum member of elastic constants, E = 71 GPa and v = 0.35. Also, determine the value for the maximum shear stress.
Answer:
i) σ1 = 133.5 MPa
σ2 = -2427 MPa
ii) 78.89 MPa
Explanation:
Given data:
ε1 = 0.0020 and ε2 = –0.0010
E = 71 GPa
v = 0.35
i) Determine the biaxial stresses σ1 and σ2 using the relations below
ε1 = σ1 / E - v (σ2 / E) -----( 1 )
ε2 = σ2 / E - v (σ1 / E) -------( 2 )
resolving equations 1 and 2
σ1 = E / 1 - v^2 { ε1 + vε2 } ---- ( 3 )
σ2 = E / 1 - v^2 { ε2 + vε1 } ----- ( 4 )
input the given data into equation 3 and equation 4
σ1 = 133.5 MPa
σ2 = -2427 MPa
ii) Calculate the value of the maximum shear stress ( Zmax )
Zmax = ( σ1 - σ2 ) / 2
= 133.5 - ( - 2427 ) / 2
= 78.89 MPa
Even though the content of many alcohol blends doesn’t affect engine drive ability using gasoline with alcohol in warm weather may cause
In particular, a system may or may not be (1) Memoryless, (2) Time invariant, (3)Linear, (4) Casual, (5) Stable.
a. True
b. False
Answer:
a. True
Explanation:
A system may be sometimes casual, time invariant, memoryless, stable and linear in particular.
Thus the answer is true.
A system is casual when the output of the system at any time depends on the input only at the present time and in the past.
A system is said to be memoryless when the output for each of the independent variable at some given time is fully dependent on the input only at that particular time.
A system is linear when it satisfies the additivity and the homogeneity properties.
A system is called time invariant when the time shift in the output signal will result in the identical time shift of the output signal.
Thus a system can be time invariant, memoryless, linear, casual and stable.
What is An ampere is
Answer:
the SI base unit of electrical current.
Answer:
An ampere is the SI base unit of electrical current
A ceramic specimen with an elastic modulus of 300 GPa is under a tensile stress of 800 MPa. Will it fracture if its most severe flaw is an internal crack of 0.30 mm long with a tip radius of curvature in the amount of 0.0015 mm? Please justify your conclusion. (Hint: Compare the largest stress in the specimen around the crack to the theoretical strength which is roughly E/10).
Answer:
16Gpa < 30 Gpa
there would be no fracture
Explanation:
fracture can occur if the maximum strength at the top of the biggest flaw is more than the theoretical fracture
to get the theoretical strength =
e/10 = 300/10
= 30 Gpa
we get the magnitude at the buggest flaw
= 2σ√a/ρt
σ = 800
ρτ = 0.0015
a= 0.3/2
[tex]=2*800\sqrt{\frac{\frac{0.3}{2} }{0.0015} }[/tex]
= [tex]=2*800*\sqrt{100} \\=2*800*10\\=16000MPa[/tex]
= 16Gpa < 30 Gpa
the fracture is not going to happen given that the maximum strenght is smaller than the theoretical fracture strength.
4. An aluminum alloy fin of 12 mm thick, 10 mm width and 50 mm long protrudes from a wall, which is maintained at 120C. The ambient air temperature is 22C. The heat transfer coefficient and conductivity of the fin material are 140 W/m2K and 55 W/mk respectively. Determine a. Temperature at the end of the fin b. Temperature at the middle of the fin. c. Calculate the heat dissipation energy of the fin
Answer:
a) 84.034°C
b) 92.56°C
c) ≈ 88 watts
Explanation:
Thickness of aluminum alloy fin = 12 mm
width = 10 mm
length = 50 mm
Ambient air temperature = 22°C
Temperature of aluminum alloy is maintained at 120°C
a) Determine temperature at end of fin
m = √ hp/Ka
= √( 140*2 ) / ( 12 * 10^-3 * 55 )
= √ 280 / 0.66 = 20.60
Attached below is the remaining answers
What possible scenarios may happen if you do the task without using PPE?
A cylindrical space capsule lands in the ocean. This capsule is 2.44 m long, 1.10 m in diameter, and weighted at one end so that it floats with its long central axis vertical and 0.820 m of its length above the water surface. The mass density of sea water is 1025 kg/m3.What is the magnitude of the buoyant force exerted on the capsule?
Answer:
The correct answer is "15456.8 N".
Explanation:
According to the question,
The inside volume will be:
= [tex]3.14\times (\frac{1.1}{2} )^2\times (2.44-0.82)[/tex]
= [tex]3.14\times \frac{1.21}{4}\times 1.62[/tex]
= [tex]3.14\times 03025\times 1.62[/tex]
= [tex]1.538757 \ m^3[/tex]
hence,
The buoyant force will be:
= [tex]V\times Pw\times g[/tex]
= [tex]1.538757\times 1025\times 9.8[/tex]
= [tex]15456.8 \ N[/tex]
The number of pulses per second from IGBTs is referred to as
An air conditioner removes heat steadily from a house at a rate of 750 kJ/min while drawing electric power at a rate of 5.25 kW. Determine (a) the COP of this air conditioner and (b) the rate of heat transfer to the outside air.Answers:(a) 2.38, (b) 1065 kJ/min
Answer:
a) the COP of this air conditioner is 2.38
b) the rate of heat transfer to the outside air is 1065 kJ/min
Explanation:
Given the data in the question;
[ Outdoor ] ← Q[tex]_H[/tex] [ W[tex]_{net, in[/tex] ] Q[tex]_L[/tex] ← [ House ]
Rate of heat removed from the house; Q[tex]_L[/tex] = 750 kJ/min = ( 750 kJ/min × ( 1 kW / 60 kJ/min ) ) = 12.5 kW
Net-work input; W[tex]_{net, in[/tex] = 5.25 kW
a) The coefficient of performance of the air conditioner; COP.
COP = Q[tex]_L[/tex] / W[tex]_{net, in[/tex]
we substitute
COP = 12.5 kW / 5.25 kW
COP = 2.38
Therefore, the COP of this air conditioner is 2.38
b) the rate of heat transfer to the outside air.
Q[tex]_H[/tex] = Q[tex]_L[/tex] + W[tex]_{net[/tex]
we substitute
Q[tex]_H[/tex] = 12.5 kW + 5.25 kW
Q[tex]_H[/tex] = 17.75 kW
Q[tex]_H[/tex] = ( 17.75 × 60 ) kJ/min
Q[tex]_H[/tex] = 1065 kJ/min
Therefore, the rate of heat transfer to the outside air is 1065 kJ/min
Water enters and leaves a pump in pipelines of the same diameter and approximately the same elevation. If the pressure on the inlet side of the pump is 30 kPa and a pressure of 500 kPa is desired for the water leaving the pump, what is the head that must be added by the pump
Answer:
The head added by the pump is approximately 51.8 meters
Explanation:
The given parameters of the water are;
The initial diameter of the pump ≈ The final diameter of the pump
The inlet side pressure, p₁ = 30 kPa
The intended outlet side pressure, p₂ = 500 kPa
The power of the pump, P = ρ·g·Q·H
Where, the pressure added by the pump, Δp = p₂ - p₁ = ρ·g·H
ρ = The density of the water ≈ 997 kg/m³
g = The acceleration due to gravity ≈ 9.81 m/s²
H = The head added by the pump
Therefore, we have;
500 kPa - 30 kPa = 997 kg/m³ × 9.81 m/s² × H
H = (500 kPa - 30 kPa)/(997 kg/m³ × 9.1 m/s²) ≈ 51.8 m
The head added by the pump, H ≈ 51.8 meters.
Type the correct answer in each box. Spell all words correctly. According to the priority matrix, which tasks should an entrepreneur complete first? According to the priority matrix, entrepreneurs should first complete tasks that are blank and important.
Answer:
Development of creative and develop ideas
Explanation:
First task as an entrepreneur is to be creative and develop ideas. The person must design the product based on which he will develop the business strategy.
The remaining activities such as marketing, fund raising, recruitment etc. comes at a later stage.
: Một nền kinh tế có cấu trúc như sau:
C = 80 + 0,8(Y - T); T = 100 ;
I = 130; G = 120;
MSr = MS/CPI = 200;
MD = 0,2Y – 10i
Yêu cầu:
1. Xác định thu nhập và lãi suất cân bằng?
2. Muốn sản lượng cân bằng tăng 500 thì chính phủ cần thay đổi thuế như thế nào?
3. Liệu mục tiêu ở câu 2 có thể đạt đựơc bằng chính sách tiền tệ hay không? Tại sao?
Answer:
Haha I'm a great guy but my friend has been in a day of the day and a lot to be able and I'm happy holi and a lot to the world of the day and day to
What is the key objective of data analysis
Answer: The process of data analysis uses analytical and logical reasoning to gain information from the data. The main purpose of data analysis is to find meaning in data so that the derived knowledge can be used to make informed decisions.
Vince is trying to figure out the volume of two mystery matters. The volume of one of the substances needs to be measured by submerging it in water and the other needs to be measured using a graduated cylinder. Based on the properties of two mystery matters, what are they? (2 points)
Group of answer choices
A rock and orange juice
Helium and a golf ball
Lemonade and milk
Orange juice and helium
Answer:
Rock and orange juice
Explanation:
The mystery matter to be submerged in water must be a solid, therefore we can eliminate the Lemonade and Milk, and Orange juice and Helium, as these pairs do not contain solids. The graduated cylinder is used to measure the volume of a liquid, therefore the only remaining option is Rock and Orange Juice.
Hi, can anyone draw me an isometric image of this shape?
. En la facultad de Ingeniería Industrial se realizó una encuesta a 200 personas para saber que lenguaje de programación preferían para aprender al inicio, se obtuvo: 50 prefieren C, 65 prefieren C#, 77 prefieren Python, 100 prefieren C o C#, 105 prefieren C# o Python, 110 prefieren C o Python, 10 personas prefieren C y Python pero no C#.
Answer:
lalalalapumpe
Explanation:
A turbine of a fossil fuel burning installation delivers 1,500 hp of mechanical energy to a generator. The generator then converts 80.0% of the mechanical energy into electrical energy. If the terminal potential difference of the generator is 1790 V, what current does it deliver (in A)
Answer:
The generator delivers current of 500.11 A
Explanation:
Given the data in the question;
mechanical energy delivered to the generator = 1500 hp
efficiency η = 80.0 %
terminal potential difference of the generator = 1790 V
we know that;
1 hp = 746 W
so
the mechanical energy delivered to the generator will be
Generator Input = ( 1500 × 746 )W = 1119000 W
So the generator output will be;
Generator Output = Generator Input × η
we substitute
Generator Output = 1119000 W × 80.0 %
Generator Output = 1119000 W × 0.8
Generator Output = 895200 W
So the Current will be;
[tex]I[/tex] = Generator Output / terminal potential difference of the generator
we substitute
[tex]I[/tex] = 895200 W / 1790 V
[tex]I[/tex] = 500.11 A
Therefore, The generator delivers current of 500.11 A
An engineer is applying dimensional analysis to study the flow of air through this horizontal sudden contraction for the purpose of characterizing the pressure drop. The flow is being modeled as constant density and steady. What is the functional relationship of the variables that characterize this situation
Answer:
The answer is " [tex]\Delta p = f(V1, p, V2, d, D, L)[/tex]"
Explanation:
Please find the complete question in the attached file.
Its change in temperature in pipes depends on rate heads and loss in pipes owing to pipe flow, contractual loss, etc.
The temperature change thus relies on V1 v2 p d D L.
An aggregate blend consists of 65% of aggregate A and 35% of aggregate B. The bulk specific gravities of aggregate A and B are 2.45 and 3.25, respectively. What is the bulk specific gravity of the blend?
a) 2.45
b) 2.68
c) 2.73
d) 2.92
Answer:
2.68
Explanation:
Percentage by Mass of each Aggregate :
Pa = 65% ; Pb = 35%;
Bulk Specific gravity of each aggregate :
Ga = 2.45 ; Gb = 3.25
Gsb = (Pa + Pb) / (Pa/Ga + Pb/Gb)
Gsb = (65 + 35) / (65/2.45 + 35/3.25)
Gsb = (65 + 35) / 37.299843
Gsb = 100 / 37.299843
Gsb = 2.68
State two factors that shows that light travels in a straight line
Explanation:
Light travels in straight lines
Once light has been produced, it will keep travelling in a straight line until it hits something else. Shadows are evidence of light travelling in straight lines. An object blocks light so that it can't reach the surface where we see the shadow.
Answer:
The two factors are Air and Object
Determine the voltage which must be applied to a 1 k 2 resistor in order that a current of
10 mA may flow.
Answer:
The correct solution is "20 volt".
Explanation:
Given that:
Current,
I = 10 mA
or,
= [tex]10\times 10^{-3} \ A[/tex]
Resistance,
R = 2 K ohm
or,
= [tex]1\times 10^3 \ ohm[/tex]
Now,
The voltage will be:
⇒ [tex]V=IR[/tex]
By putting the values, we get
[tex]=10\times 10^{-3}\times 2\times 10^{3}[/tex]
[tex]= 20 \ volt[/tex]
Things to be done before isolation
