Answer:
a) 46.76 Lsun
b) 2187 Lsun
c ) You can easily estimate the luminosity of a 3-solar massed giant star because its luminosity is close to the luminosity of the sun
Explanation:
To estimate the luminosity of a celestial body in terms of solar luminosity we use the expression below
= [tex]\frac{L}{Lsun} = (\frac{M}{Msun} )^{3.5}[/tex]
a) Estimate the luminosity of a 3 solar mass main sequence star
= [tex]\frac{L}{Lsun} = (\frac{3M}{Msun} )^{3.5}[/tex]
Hence ; L(luminosity of a 3 solar mass star ) = 46.76 Lsun
b) Estimate the luminosity of a 9-solar-mass main sequence star
= [tex]\frac{L}{Lsun} = (\frac{9M}{Msun} )^{3.5}[/tex]
hence L( luminosity of a 9-solar mass star ) = 2187 Lsun
c ) You can easily estimate the luminosity of a 3-solar massed giant star because its luminosity is close to the luminosity of the sun
A) The luminosity of a 3 -solar-mass main-sequence star is; L = 46.765L_sun
B) The luminosity of a 9 -solar-mass main-sequence star is; L = 2187L_sun
C) Yes, we can easily estimate the luminosity of a 3 -solar-mass main-sequence star.
We want to find luminosity of a solar body which in this case is a main sequence star. The formula in terms of solar luminosity is;
L/L_sun = (M/M_sun)^(3.5)
Where;
L is luminosity of the solar body
L_sun is luminosity of the sun
M is mass of the solar body
M_sun is mass of the sun
A) Thus;
For a 3 -solar-mass main-sequence star;
M = 3M_sun
Therefore;
L/L_sun = (3M_sun/M_sun)^(3.5)
L/L_sun = 3^(3.5)
L/L_sun = 46.765
L = 46.765L_sun
B) For a 9-solar-mass main-sequence star;
L/L_sun = (9M_sun/M_sun)^(3.5)
L/L_sun = 9^(3.5)
L/L_sun = 2187
L = 2187L_sun
C) We can see from answer A above that the luminosity of a 3 solar mass body is 46.765 times of the luminosity of sun. Since it's not so much bigger than the luminosity of sun, then it is easy to estimate.
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Write a python script using while loop which display the number list with an increment of 3 between 1 and 25. Display the output in one row as shown.
Answer:
num_count = 0
while num_count < 25:
print(num_count)
num_count += 3
Explanation:
A while loop statement is defined in the python source code above. An integer variable 'num_count' is defined and continuously incremented by three in the loop until it is greater than 25. the output of the while loop between 1 and 25 is print on the screen.
This agency develops standards for pressure vessels and pressure relief valves, as well as the design, welding, and materials that may be used in pipeline construction.
Select one:
a. American Petroleum Institute
b. American Society of Mechanical Engineers
c. American Gas Association
d. National Fire Protection Association
Answer:
b. American Society of Mechanical Engineers
Explanation:
The "American Society of Mechanical Engineers" (ASME) is an organization that ensures the development of engineering fields. It is an accreditation organization that ensures parties will comply to the ASME Boiler and Pressure Vessel Code or BPVC.
The BPVC is a standard being followed by ASME in order to regulate the different pressure vessels and valves. Such standard prevents boiler explosion incidents.
Ignoring reflection at the air-soil boundary, if the amplitude of a 3-GHz incident wave is 10 V/rn at the surface of a wet soil medium, at what depth will it be down to 1 mV/m? Wet soil is characterized by µr = 1, εr = 9, and σ = 5 × 10–4S/m.
Answer:
5 multiply by 10 S/M
Based on the calculations, the incident wave would be down to 1 mV/m at a depth of 287.82 meters.
How to calculate the depth of the wet soil medium.Since the medium is a wet soil, it is characterized by the following:
Dielectric constant, µr = 1.Relative permitivitty, εr = 9.Electrical conductivity, σ = 5 × 10⁻⁴ S/m.Next, we would determine loss tangent, so as to know if the wet soil is a low-loss medium:
For a low-loss medium; ε''/ε' = σ/ωε < 0.01.
[tex]\frac{\sigma}{\omega \epsilon} = \frac{5 \times 10^{-4} \;\times\; 36 \pi}{2\pi \;\times \;3 \times 10^9\; \times\; 10^{-9} \times \;9} \\\\\frac{\sigma}{\omega \epsilon} =3.32 \times 10^{-4}[/tex]
Therefore, the wet soil medium is a low-loss dielectric and its absorption (attenuation) coefficient is calculated by using this formula:
Note:
[tex]\alpha = \frac{\sigma}{2}\sqrt{\frac{\mu}{\epsilon}} \\\\\alpha = \frac{\sigma}{2} \times \frac{120\pi}{\sqrt{\epsilon_r} } \\\\\alpha =\frac{5 \times 10^{-4} \times 120\pi}{2 \times \sqrt{9} } \\\\[/tex]
α = 0.032 Np/m.
Now, we calculate the depth:
[tex]E(z) = E_oe^{-\alpha z} = 10e^{-\alpha z}\\\\10^{-3}=10e^{-0.032 z}\\\\ln(10^{-4})=-0.032 z\\\\-9.21 \times 10^9=-0.032z\\\\z=\frac{-92.1 0}{-0.032}[/tex]
z = 287.82 meters.
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What contacts do you use to turn on a load when the coil is energized?
Answer:
Contactors can be field mounted easily and are compact in size. Generally, these electrical devices feature multiple contacts. These contacts are in most cases normally open and provide operating power to the load when the contactor coil is energized. Contactors are most commonly used for controlling electric motors.
Explanation:
20 points and brainliest is it A, B, C, D
Which of the following OSHA colors would you expect to find around material that is awaiting repair?
A. red
B. blue
C. green
D. yellow
Answer:
I think is B
Explanation:
Consider a simple ideal Rankine cycle with fixed turbine inlet temperature and condenser pressure. What is the effect of increasing the boiler pressure on:_______.
Pump work input: (a) increase (b) decrease (c) remains the same
Turbine work output: (a) increase (b) decrease (c) remains the same
Heat supplied: (a) increase (b) decrease (c) remains the same
Heat rejected: (a) increase (b) decrease (c) remains the same
Cycle efficiency: (a) increase (b) decrease (c) remains the same
Moisture content at turbine exit: (a) increase (b) decrease (c) remains the same
Answer:
increaseincreasedecreasedecreaseincreaseincreaseExplanation:
EFFECT OF INCREASING THE BOLIER PRESSURE ON
pump work output ; IncreaseTurbine work output ; IncreaseHeat supplied ; Decrease and this is because the latent heat been supplied will decrease when there is an increase in pressureHeat Rejected ; Decreasecycle efficiency ; Increase, the increase in the cycle efficiency increases in a very significant amount/rate because cycle efficiency = power output / heat inputMoisture content at Turbine exit ; IncreasesWhat is one step taken when solving a computer software problem? making sure the power cord is plugged in properly scanning the computer and deleting any viruses searching for any spills or damage to the computer taking a look at all the cables and connectors when students have computer trouble they usually are expected to make any simple fixes on their own. solve complex issues by themselves. drop their school work until it is resolved. pay a technician a high fee to fix the issue.
Answer:
Answer: B) Scanning the computer and deleting any viruses.
Explanation:
Some of the feedback I hear from new developers working on a programming problem revolves around uncertainty of where to start. You understand the problem, the logic, basics of the syntax, etc. If you see someone else’s code or have someone to guide you, you can follow along. But maybe you feel uncertain about doing it yourself and have trouble turning your thoughts into code at first even though you understand the syntax or logic. Here’s my process and some tips to tackling a sample problem that hopefully some of you may find helpful in your journey.
If you need further expenation then:
Some of the feedback I hear from new developers working on a programming problem revolves around uncertainty of where to start. You understand the problem, the logic, basics of the syntax, etc. If you see someone else’s code or have someone to guide you, you can follow along. But maybe you feel uncertain about doing it yourself and have trouble turning your thoughts into code at first even though you understand the syntax or logic. Here’s my process and some tips to tackling a sample problem that hopefully some of you may find helpful in your journey.
May i please have brainliest
Answer:
B. scanning the computer and deleting any viruses
Explanation:
I took the test on edge, and this makes most sense to me. Good luck:)
25 points and brainliest is it A, B, C, D
Which option distinguishes the PPE violations in the following scenario that could lead to the most serious injury?
Rey is mixing different liquids for the farm's special pesticide blend. The containers are heavy and awkward to handle. Rey is wearing coveralls, with an apron slung over his shoulder, and safety goggles around his neck; he is wearing leather gloves and tennis shoes. Rey's supervisor walks in and immediately tells him to stop working. Rey is then written up for not following shop safety rules regarding PPE.
A. having an apron over his shoulder
B. having safety goggles around his neck
C. wearing leather gloves instead of nitrile gloves
D. wearing tennis shoes instead of steel-toed boots
Answer:
SIR IT IS D HOPE THIS HELPS (☞゚ヮ゚)☞☜(゚ヮ゚☜)
Explanation:
A ________ is a condition or capability needed by a user to solve a problem or achieve an objective that satisfies a standard or specification or any other formally documented need.
What is civil engineering? Use in your own words dont copy off the internet
Answer: Civil engineering is a branch in engineering which deals with design, construction, and building structures such as dam, bridges etc....
Explanation:
What type of brake uses the inside of each rear wheel hub and rotor assembly as a parking brake drum?
Answer:A rear disc/drum parking brake uses the inside of each rear wheel hub and rotor assembly as a parking brake drum
Explanation:
The interior of each rear wheel hub and rotor assembly serves as a parking brake drum in a rear disc/drum parking brake.
What is a brake drum?A drum brake is a type of brake that relies on friction created by a set of shoes or pads pressing outward against a rotating cylinder-shaped part known as a brake drum.
Drum brakes are commonly used to describe brakes in which shoes press against the inner surface of the drum.
Drum brakes provide consistent braking force regardless of whether the vehicle is moving forward or backward.
This is due to the fact that drum brakes produce the same braking force in both directions. This type is typically found on passenger car rear brakes.
Thus, in a rear disc/drum parking brake, the interior of each rear wheel hub and rotor assembly serves as a parking brake drum.
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Es una de las alternativas para obtener capital y como facilidad puede ayudarte a financiarte por más de 40 días, contando con el capital para pagar el saldo.
Answer:
Apalancamiento.
Explanation:
El apalancamiento es el uso de dinero prestado (deuda) para aumentar el rendimiento esperado del capital. El apalancamiento se mide como la relación entre la deuda que devenga intereses y los activos totales. Cuanto mayor sea la deuda que devenga intereses, mayor será el apalancamiento financiero o "aceleración". Esto puede tener un efecto positivo o negativo.
Los costos por intereses de este capital de préstamo suelen ser fijos y se deducen de los ingresos. Un préstamo permite que una organización genere más ingresos sin un aumento necesario en el capital. Como no es necesario recaudar ni mantener capital social adicional, no se requieren pagos de dividendos adicionales (que no se pueden deducir de las ganancias). Sin embargo, un alto apalancamiento puede ser beneficioso durante los tiempos de auge, pero puede conducir a serios problemas de flujo de efectivo durante una recesión, ya que es posible que no haya suficientes retornos para cubrir mayores costos de intereses y obligaciones de reembolso.
A spur gearset has a module of 6 mm and a velocity ratio of 4. The pinion has 16 teeth. Find the number of teeth on the driven gear, the pitch diameters, and the theoretical center-to-center distance
Answer:
NG=64 teeth
dG=384mm
dP=96mm
C=240mm
Explanation:
step one:
given data
module m=6mm
velocity ratio VR=4
number of teeth of pinion Np=16
Step two:
Required
1. Number of teeth on the driven gear
[tex]N_G=N_P*V_R\\\\N_G=16*4\\\\N_G=64[/tex]
The driven gear has 64 teeth
2. The pitch diameters
The driven gear diameter
[tex]d_G=N_G*m\\\\d_G=64*6\\\\d_G=384[/tex]
The driven gear diameter is 384mm
The pinion diameter
[tex]d_P=N_P*m\\\\d_P=16*6\\\\d_P=96[/tex]
Pinion diameter is 96mm
3. Theoretical center-to-center distance
[tex]C=\frac{d_G+d_P}{2} \\\\C=\frac{384+96}{2} \\\\C=\frac{480}{2}\\\\C=240[/tex]
The theoretical center-to-center distance is 240mm
The results are listed below:
The driven gear has 64 teeth.The pinion has a diameter of 96 millimeters and the driven gear has a diameter of 384 millimeters.The theoretical center-to-center distance is 240 millimeters.First, we proceed to find the number of teeth of each gear ([tex]N_{D}, N_{P}[/tex]) based on the fact that gear only fit when they have the same module ([tex]m[/tex]). The velocity ratio ([tex]r_{v}[/tex]) is defined by the following relationship:
[tex]r_{v} = \frac{N_{D}}{N_{P}}[/tex] (1)
If we know that [tex]r_{v} = 4[/tex] and [tex]N_{P} = 16[/tex], then the number of teeth of the driven gear is:
[tex]N_{D} = r_{v}\cdot N_{P}[/tex]
[tex]N_{D} = 4\cdot (16)[/tex]
[tex]N_{D} = 64[/tex]
The driven gear has 64 teeth.
The pitch diameter ([tex]D[/tex]) is obtained by multiplying the number of teeth ([tex]N[/tex]) by module ([tex]m[/tex]), in milimeters.
Pinion
[tex]D_{P} = m\cdot N_{P}[/tex] (2)
([tex]m = 6\,mm[/tex], [tex]N_{P} = 16[/tex])
[tex]D_{P} = (6\,mm)\cdot (16)[/tex]
[tex]D_{P} = 96\,mm[/tex]
Driven gear
[tex]D_{D} = m\cdot N_{D}[/tex] (3)
([tex]m = 6\,mm[/tex], [tex]N_{D} = 64[/tex])
[tex]D_{D} = (6\,mm)\cdot (64)[/tex]
[tex]D_{D} = 384\,mm[/tex]
The pinion has a diameter of 96 millimeters and the driven gear has a diameter of 384 millimeters.
Lastly, the theoretical center-to-center distance is calculated by the following formula:
[tex]d = \frac{1}{2}\cdot (D_{P}+D_{D})[/tex] (4)
([tex]D_{P} = 96\,mm[/tex], [tex]D_{D} = 384\,mm[/tex])
[tex]d = \frac{1}{2}\cdot (96\,mm + 384\,mm)[/tex]
[tex]d = 240\,mm[/tex]
The theoretical center-to-center distance is 240 millimeters.
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Calculate the reflection loss that is incident normal to the surface of a triple pane window (assume n for window glass is 1.5)
Answer: the reflection loss is 4%
Explanation:
Given that;
n for window glass is 1.5
we know that
Reflection Loss rλ = (nλ - 1)² / (nλ + 1)²
the reflection of loss rλ at normal incidence between two media with different refractive indexes rλ = n'/n, the ratio indices
where n is index of refraction of air ( 1 )
and n' is the refraction of window glass ( 1.5 )
our nλ is 1.5
so we substitute into the equation
rλ =[ (1.5 - 1)² / (1.5 + 1)²] × 100
= [0.25 / 6.25] × 100
= 0.04 × 100
= 4%
Therefore the reflection loss is 4%
Water flows with an average velocity of 1.0 m/s and a normal depth of 0.5 m in a wide rectangular channel. Is the flow subcritical or supercritical?
Answer:
Subcritical
Explanation:
To compute the grouse number
We use this formula
F = v/√gy
From this question
V = 1 m
G = 9.81m/sec²
Y = 0.5
When we insert this into the grouse formula
F = 1m/s / √ 9.8m/sec² x 0.5m
= 0.451< 1
Therefore we conclude that the grouse is less than 1 and so the flow is subcritical.
A car is driven over a curb twice—once very slowly and once quite rapidly. What would you need to know about the car in the second case that you did not need to know in the first case if you were required to find the tire force that resulted from going over the curb?
Answer:
You'd need to know things like the weight of the car, the spring constant of the suspension springs.
Explanation:
Driving over the curb slowly does not have much of an "impact" because of the small potential energy it has but to find the force that results from going over the curb at a much higher speed, you would need to know the weight of the car since it directly impact the force that it applies. You also would need to know about the car's suspension, the spring material, how stiff the springs are and their spring constant to calculate the force they absorb.
I hope this answer helps.
3. A steel pipe of outside diameter 20 mm and thickness 3 mm is
deflected by 3 mm when used as a beam supported at its ends, 1
m apart, and subjected to a central load of 170 N. Find the
buckling load when the pipe is used as a column with hinged
ends. What is the maximum lateral deflection of this column
before the material attains the yield stress of 250N/mm??
The answer is explained in the picture. Thank you. Rate it
An individual eats fish from a river contaminated with benzene. What concentrations of benzene in water (mg/L) would produce a lifetime cancer risk of 10-6 to an individual who eats 2 meals of fish per week for 30 years if the BCF for benzene is 10+3?
This question is incomplete, the complete question is;
An individual eats fish from a river contaminated with benzene. What concentrations of benzene in water (mg/L) would produce a lifetime cancer risk of 10⁻⁶ to an individual who eats 2 meals of fish per week for 30 years if the BCF for benzene is 10⁺³?
Answer:
0.021 mg/L concentration of benzene in water would produce a lifetime cancer risk 10⁻⁶ to an individual who eats 2 meals of fish per week for 30 years if the BCF for benzene is 10⁺³
Explanation:
Chronic daily intake (CDI) =(C/W) (Intake rate/ lifetime) ( Exposure)
values from EPA Exposure Factors Table)
CDI = [ (5.2 L/d × C mg/L 0.054 kg/d) / 70 kg] [30/70] [350/365]
CDI = 1.65 × 10⁻³C
Now concentration of benzene; ( RISK) = CDI × pF
= 10⁻⁶ = [2.9× 10⁻² / (MG/kg-d)] ( 1.65 × 10⁻³C)
C = 0.021 mg/L
Therefore 0.021 mg/L concentration of benzene in water would produce a lifetime cancer risk 10⁻⁶
Which of the following is used to estimate the size of a room?
A) Drop ceilings
B) Window frames
C) Bricks
D) Room trim
Answer:
I think the answer is drop ceilings
Explanation:
A large room contains moist air at 30oC, 102 kPa. The partial pressure of water is 1.5 kPa. Determine(a) the relative humidity(b) the humidity ratio, in kg(vapor) per kg(dry air)(c) the dew point temperature, in oC(d) the mass of dry air, in kg if the mass of water vapor is 10 kg
Solution :
Given :
Dry bulb temperature, T = 30 degree C
Absolute pressure, P = 102 kPa
Partial pressure of water vapor, [tex]$P_v$[/tex] = 1.5 kPa
a). Relative humidity is given by
[tex]$\phi = \frac{P_v}{P_{sat}}$[/tex]
At T = 30 degree C, from the steam table, we have saturation temperature as 4.2469 kPa.
[tex]$\phi = \frac{1.5}{4.2469}$[/tex]
= 0.35319
= 35.31 %
b). Humidity ratio,
[tex]$w= 0.622 \times \frac{P_v}{P-P_v}$[/tex]
[tex]$w= 0.622 \times \frac{1.5}{102-1.5}$[/tex]
w = 0.009283 kg per kg of dry air
c). Dew point temperature is the saturation temperature at vapor pressure of air (can be found from steam table)
At [tex]$P_v$[/tex] = 1.5 kPa, saturation temperature = 1.02 degree C
∴ Dew point temperature = 13.02 °C
d). Humidity ratio can be be defined as the ratio of mass of water vapor to the mass of dry air.
i.e. [tex]$w=\frac{m_v}{m_a}$[/tex]
[tex]$0.009283 =\frac{10}{m_a}$[/tex]
∴ [tex]m_{a}[/tex] = 1077.170 kg of dry air
Scientists learn more about the natural world through investigation. This involves identifying a problem, researching related information, designing and conducting an investigation, analyzing the results, evaluating the conclusion, and communicating the findings. Engineers follow similar steps when creating new products or solutions through technological design. The four stages of technological design include identifying a need, designing and implementing a solution, and evaluating the solution.
Answer:
This shows that the technological designs are similar to the scientific investigation processes.
Explanation:
Scientists carry out scientific investigations and discoveries. They learn from their environment by investigating the natural world. The scientist investigates by problem identification, research the related information, designing and conceptualizing, investigating and analyzing the results and deriving out conclusions.
Similarly the engineers follow the same step and provide solutions to the problems of the society through their products and technological designs. The engineers first identify the need of the product, design and implement the design to provide solution and then evaluate the solution. These are the similar steps that an engineer follow in a technological design of a product or a solution.
Determine the complex power, apparent power, average power absorbed, reactive power, and power factor (including whether it is leading or lagging) for a load circuit whose voltage and current at its input terminals are given by:
a. v(t)= 100cos(377t - 30°) V
i(t)= 2.5cos(377t- 60°) A
b. Vrms= 110e^j60 , Irms= 3e^j45 A
Answer:
A) complex power = apparent power = ( 108.253 + 62.5 i ) VA
active power = 108.25 watts
reactive power = 62.5 VAR'S
power factor = cos ∅ = cos 30° = 0.866 ( lagging )
also ; current lags voltage by 30°
B) your question is not well written hence no answer
Explanation:
A) v(t) = 100 cos (377t - 30° ) v
Vrms = [tex]\frac{100}{\sqrt{2} }[/tex] ∠ -30°
I(t) = 2.5cos(377t- 60°) A
Irms = [tex]\frac{2.5}{\sqrt{2} }[/tex] ∠ -60°
determine complex power apparent power . ...... power factor
Note : complex power = apparent power
=( Irms ) * Vrms
= ( [tex]\frac{2.5}{\sqrt{2} }[/tex] ∠ -60° ) * ( [tex]\frac{100}{\sqrt{2} }[/tex] ∠ -30° )
= 125 ∠ 30°
= ( 108.253 + 62.5 i ) VA ( complex power )
active power = 108.25 watts
reactive power = 62.5 VAR'S
power factor = cos ∅ = cos 30° = 0.866 ( lagging )
current lags voltage by 30°
Suppose to build RSA crypto system you picked primes "p" and "q" as 3 and 7 and "e" as 5 what are the public and private keys? What is the encryption of a message whose integer equivalent is 12. Show that the decryption gives back the message 12.
Answer:
1) Public key of the receiver is (e, n) is (5, 21) and Private key of the receiver (d, n) is (5 , 21) ,
2) the encryption of a message whose integer equivalent is 12 is 3
3) Decryption of the message ⇒ P = C^d mod n
⇒ P = 3⁵ mod 21
⇒ P = 243 mod 21
⇒ 12
Explanation:
Given that,
p = 3
q = 7
e = 5
1)
Now, n = pq = 3 × 7 = 21
Ø(n) = (p-1) × (q-1) = 2 × 6 = 12
Public key of the receiver is (e, n) is (5, 21)
and private key of the receiver is (d, n)
we have to find 'd' by using the expression
ed = 1 + kmodØ(n)
d = 1 + kmodØ(n) / e
now to get 'd' , we need to choose the least positive integer 'k', by substituting different values of ‘k’ from 0,
so for k =0 , d = (1+0) / 5 = 0.2 not an integer.
for k =1 , d = (1+12) / 5 = 13/5 = 2.6 not an integer.
for k =2 , d = (1+24) / 5 = 5 , now 5 is an integer
So k = 2 and d = 5
Private key of the receiver (d, n) is (5 , 21)
2)
Now the encryption of a message whose integer equivalent is 12?
Encryption of the message ⇒ C = P^e mod n
⇒ C = 12⁵ mod 21
⇒ 248832 mod 21
⇒ 3
3)
Also the decryption gives back the message 12.
Decryption of the message ⇒ P = C^d mod n
⇒ P = 3⁵ mod 21
⇒ P = 243 mod 21
⇒ 12
Some refrigerants contain CFCs
A) True
B) false
???????
Answer:
true ...............
Some refrigerants R11, R12, and R115 contain CFC. The statement is true.
What is chlorofluorocarbon?Chlorofluorocarbons (CFCs), as the name suggests, are compounds made of the atoms of fluorine, chlorine, and carbon. Because they are neither hazardous nor combustible, they have a variety of uses, including in refrigeration. Refrigeration is the process of maintaining the temperature of the required space cooler than that of an atmosphere.
As the public learned in 1974 that CFCs were alarmingly destroying the ozone layer, most CFCs were outlawed, and by 1995, their manufacture of them had virtually ended worldwide. CFCs were replaced with other products since they were no longer produced and the things they were used for required new products.
Therefore, some refrigerants R11, R12, and R115 contain CFC. The statement is true.
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Calculate the cost per cubic yard to place concrete using each of the alternatives described. The work in both cases consists of placing 140 cubic yards of concrete in footings.
a. Using a crane and bucket at a price of $225 per hour, including an operator, with a crew consisting of 6 laborers, a cement finisher, and a foreman. The concrete will be placed in 7 hours using this setup, and transportation of the crane costs $390.
b. Using a concrete pump at a price of $295 per hour, including an operator and a crew consisting of 5 laborers, a cement finisher, and a foreman. With this setup, concrete is placed in 6 hours and transportation of the pump costs $290.
Answer:
Cost per cubic yard to place concrete using each of the following alternatives:
Alternative a = $14.04
Alternative b = $14.71
Explanation:
a) Data and Calculations:
Work of concrete in footings = 140 cubic yards
a. Price of using crane and bucket = $225 per hour
Number of hours required for this setup = 7 hours
Transportation of the crane = $390
Therefore, total cost under this alternative = $1,965 (($225*7) + $390)
Cost per cubic yard = $14.04 ($1,965/140)
b. Price of using a concrete pump = $295 per hour
Number of hours required for this setup = 6 hours
Transportation of the pump = $290
Therefore, total cost under this alternative = $2,060 (($295*6) + $290)
Cost per cubic yard = $14.71 ($2,060/140)
A cyclist is turning the pedals of his bicycle at a speed of 60RPM while exerting a torque of 1 lb-ft. The input sprocket has 40 teeth. What is the number of teeth on the output sprocket, if the driven wheel is rotating at 240 RPM?
Answer:
10
Explanation:
The speed of the chain is the same for both sprockets.
vᵢ = vₒ
ωᵢ rᵢ = ωₒ rₒ
The sprockets have the same pitch, so the radius is proportional to the number of teeth. So we can say:
ωᵢ nᵢ = ωₒ nₒ
Plugging in values:
(60 rpm) (40) = (240 rpm) nₒ
nₒ = 10
The output sprocket has 10 teeth. This makes sense, if the output sprocket is 4 times smaller, it will turn 4 times faster than the input sprocket.
Answer: it is 10 teeth and the guy under me already explained soo
Explanation:
A 1-in (internal diameter) pipe is used to supply water to a low-pressure tank with an MAWP of 20 psig. The water is supplied through a regulator from a source with a maximum pressure of 100 psig. Determine the diameter of a conventional spring-operated relief required to protect the vessel from a regulator failure. Be sure to state clearly any assumptions and your justifications for them.
Answer:
3.4 inches
Explanation:
Determine the diameter required to protect the vessel from a regulator failure ( relief diameter )
A = [tex]\frac{\pi d^2}{4}[/tex]
Hence d = [tex]\sqrt{\frac{4A}{\pi } }[/tex] = [tex]\sqrt{\frac{4 * 9.08}{\pi } }[/tex] = 3.4 inches
attached below is the remaining part of the solution
Which personal protective equipment (PPE) should you wear when working around asbestos-containing materials?
A) Respiratory protectionB) Protective work clothing, including gloves C) Face shields and/or vented goggles D) All of the above
Answer:
d
Explanation:
yea
Answer:
D
Explanation:
A fan draws air from the atmosphere through a 0.30-mdiameter round duct that has a smoothly rounded entrance. A differential manometer connected to an opening in the wall of the duct shows a vacuum pressure of 2.5 cm of water. The density of air is 1.22 kg/m3 . Determine the volume rate of air ow in the duct in cubic feet per second. What is the horsepower output of the fan?
Answer:
V = 50 ft³/s
H.P = 0.466
Explanation:
Given that
Diameter of the duct, D = 0.3 m
Vacuum Pressure of the duct, Z = 0.025 m
P(w) = pressure of water, 1000 kg/m³
P(a) = pressure of air, 1.22 kg/m³
To find the pressure change we use the formula
ΔP = P(w) * g * Z
ΔP = 1000 * 9.8 * 0.025
ΔP = 245 Pa.
We need the area, do we find that too
A = πd²/4
A = π * 0.3² * 1/4
A = 0.071 m²
Recall the energy equation to be
1/2v² = ΔP/p(a) , so that if we rearrange, we have
v² = 2ΔP/p(a)
v = √(2ΔP/p(a)), on substituting the values, we have
v = √(2 * 245)/1.22
v = √490/1.22
v = √401.64
v = 20.04
The volume flow rate is then equal to
Velocity * Area.
V = 20.04 * 0.071
V = 1.42 m³/s, converting to ft³/s, we have 50 ft³/s
Horsepower output is gotten using
P = ΔP * V
P = 245 * 1.42
P = 347.9 w, converting this to HP, we have 0.466 HP
A source outputs data at the rate of 1,000,000 bits/sec. The transmitter uses binary PAM with raised cosine pulse shaping. If the ideal baseband channel has a cutoff frequency of 850 kHz, what is the maximum roll-off factor that can be applied to the pulse shaping?
Answer:
maximum roll-off factor is 0.7
Explanation:
given data
rate of output data = 1,000,000 bits/sec
cutoff frequency fc = 850 kHz
solution
we know bandwidth frequency is same as that of bandwidth
we apply here fc formula that is
fc = ω ( 1 + α ) ..........1
here
ω = data rate ÷ 2 .............2
ω = 1000 ÷ 2
ω = 500000 Hz
so put now value in eq 1
fc = ω ( 1 + α )
850000= 500000 ( 1 + α )
solve it we get
α = 0.7
so, maximum roll-off factor is 0.7