Answer:
Environmental science and protection technicians both use laboratory equipment, such as microscopes, to analyze samples collected in the field. Environmental science and protection technicians also monitor the environment and investigate sources of pollution and contamination, including those affecting public health.
Hope this was helpful ;)
answer is a and b jjjjxjxjxjxjx xxxjxjxj
35 points an brainiest if correct
Which of the following nails would most likely be used in securing a delicate, decorative piece of thin wood trim to a cabinet face?
2d
10d
60d
100d
Calculate the radius of a vanadium atom, given that it has a BCC crystal structure, density of 5.96 g/cm3, and an atomic weight of 50.9 g/mol (Max. pts. 5).
Answer:
The answer is "[tex]\bold{1.32 \times 10^{-3} \ cm}[/tex]".
Explanation:
All of the atoms in a BCC crystalline structure are contained in the 8-corner unit cell.
Each corner connects the atom to a single cell [tex]\frac{1}{8}[/tex]
Therefore, the unit cell number of atoms:
[tex]= 8 \times \frac{1}{8}+ 1 \\\\= 1+1 \\\\= 2 \ atom[/tex]
[tex]The mass unit cell = \frac{ \text{Number of atoms} \times \text{atomic weight}} {Avagadro number}\\\\= \frac{2 \times 50.9}{6.023 \times 10^{23}} \\\\= 1.69 \times 10^{-22} \ g\\\\Area Of the atom= \frac{4r}{\sqrt{3}}\\\\ 5.96 = \frac{1.69 \times 10^{-22}}{volume}\\\\volume= 2.835 \times 10^{25}\\\\v=d^3\\\\v= (\frac{4r}{\sqrt{3}})^3\\\\\to 2.835 \times 10^{-23} \times (\sqrt{3})^3 = 4^3 r^3[/tex]
[tex]\to \sqrt[3]{\frac{{2.835 \times 10^{-23} \times (\sqrt{3})^3}}{4^3}} =r\\\\\to r= 1.32 \times 10^{-3} \ cm[/tex]
simple Brayton cycle using air as the working fluid has a pressure ratio of 10. The minimum and maximum temperatures in the cycle are 295 and 1240 K. Assuming an isentropic efficiency of 83 percent for the compressor and 87 percent for the turbine, determine (a) the air temperature at the turbine exit, (b) the net work output, and (c) the thermal efficiency.
Answer:
a) 764.45K
b) 210.48 kJ/kg
c) 30.14%
Explanation:
pressure ratio = 10
minimum temperature = 295 k
maximum temperature = 1240 k
isentropic efficiency for compressor = 83%
Isentropic efficiency for turbine = 87%
a) Air temperature at turbine exit
we can achieve this by interpolating for enthalpy
h4 = 783.05 kJ/kg ( calculated in the background ) at state 4 using Table A-17 for Ideal gas properties of air
T4 ( temperature at Turbine exit ) = 760 + ( 780 - 760 ) [tex](\frac{783.05-778.18}{800.13-778.18} )[/tex] = 764.45K
b) The net work output
first we determine the actual work input to compressor
Wc = h2 - h1 ( calculated values )
= 626.57 - 295.17 = 331.4 kJ/kg
next determine the actual work done by Turbine
Wt = h3 - h4 ( calculated values )
= 1324.93 - 783.05 = 541.88 kJ/kg
finally determine the network output of the cycle
Wnet = Wt - Wc
= 541.88 - 331.4 = 210.48 kJ/kg
c) determine thermal efficiency
лth = Wnet / qin ------ ( 1 )
where ; qin = h3 - h2
equation 1 becomes
лth = Wnet / ( h3 - h2 )
= 210.48 / ( 1324.93 - 626.57 )
= 0.3014 = 30.14%
I can't log in even though it says all ages are accepted.Instead when I TRY logging in it says this. "We're sorry, but we are not able to complete your registration at this time". And I have tried refreshing the page and and X-ing out of the tab and restarting my computer and it doesn't work! And I know people aren't that crazy to get a account for brainly. Please help me out I really need a answer.
Answer:
Explanation:
This is not a question so to say. This is more like a complaint about how the platform works. Are you needing help with solving a personal problem or having troubles with the platform in itself
The water in a soil flows from Point K to Point L, a distance of 250 ft. Point K is at elevation 543 ft and Point L is at elevation 461 ft. Piezometers have been installed at both points, and their water levels are 23 ft and 74 ft, respectively, above the points. Compute the average hydraulic gradient between these two points.
Answer:
0.124
Explanation:
We calculate the hydraulic gradient by the formulas below.
I = (change in h)/(change in l)-----eqn 1
I = (hk-hl)/change in L ----- equation 2
At k the headloss = hk,
At L the headloss = hL
The distance of water travel is change in I
Total head at k
hk = 543+23
= 566 ft
Total head at L
hL = 461+74
= 535 ft
Change in L = 250
When we substitute these values in equation 2
566-535/250
= 0.124
The hydraulic gradient is 0.124
A segment of a roadway has a free flow speed of 45 mph and a jam density of 25 ft per vehicle. Determine the maximum flow and at a flow rate of 1950 vph
Answer:
2376 vph
Explanation:
Given data
free flow speed ( Vf ) = 45 mph
Jam density = 25 ft per vehicle
flow rate = 1950 vph
first we calculate the Jam density in vehicle /mile
= 5280 / 25 = 211.2 vehicle/mile
where ; 1 mile = 5280 feet
The maximum flow can be calculated using Greenshield method
q = ( Vf * jam density ) / 4 = ( 45 * 211.2 ) / 4
= 2376 vph
The current through a 0.1 Henrys (H) inductor is i(t) = 10 t e^-5tA. Find the voltage across the inductor.
a. v(t) = 10 te^-5t V
b. v(t) = 0.1 (10te^-5t) V
c. v(t) = 5te^-5t V
d. v(t) = (1 - 5t) e^-5t V
Answer: d. [tex]v(t)=(1-5t)e^{-5t}[/tex]V
Explanation: Inductance is a property of an inductor: when there is a change in current passing through a conductor, it creates a voltage in the conductor itself and in the other conductors. Inductance unit is Ω.s or henry (H)
So, the relation between Voltage and Current in an inductor is given by
[tex]v=L\frac{di}{dt}[/tex]
in which
L is inductance in H
i is current in A
Current is [tex]i(t)=10te^{-5t}[/tex], so, derivative will be:
[tex]\frac{di}{dt}=10e^{-5t}+10t(-5)e^{-5t}[/tex]
[tex]\frac{di}{dt}=10e^{-5t}-50te^{-5t}[/tex]
[tex]\frac{di}{dt}=10e^{-5t}(1-5t)[/tex]
Then, voltage is
[tex]v=0.1.10.e^{-5t}(1-5t)[/tex]
[tex]v=(1-5t)e^{-5t}[/tex]
Voltage across the 0.1H inductor is [tex](1-5t)e^{-5t}[/tex] V
25 points and brainiest if correct A, B, C, D
Which option identifies whether Juna's answer in the following scenario is right, and correctly explains why or why not?
The problem asks to convert 63" to its feet and inches equivalent. Juna's answer is 5' .
A. Juna's answer is correct because both the number of feet and the number of inches are correct.
B. Juna's answer is correct because although the number of inches is wrong, the number of feet is correct.
C. Juna's answer is incorrect because even though the number of feet is correct, the number of inches is wrong.
D. Juna's answer is incorrect because even though the number of inches is correct, the number of feet is wrong.
Answer:
A. Juna's answer is correct because both the number of feet and the number of inches are correct
Explanation:
Water at 70 kPa and 1008C is compressed isentropically in a closed system to 4 MPa. Determine the final temperature of the water and the work required, in kJ/kg, for this compression.
Answer:
The answer is "909.3928 KJ".
Explanation:
[tex]70 \ kPa \ \ and \ \ 100^{\circ}C \\\\s_i= 7.56162\ \frac{kJ}{kgK}\\\\u_i= 2509.39 \ \frac{kJ}{kg}\\\\[/tex]
The method is isentropic since the cylinders are shielded.
Calculating the work:
[tex]w= u_2-u_i \\\\[/tex]
[tex]= 3418.7728-2509.38 \\\\=909.3928 \ KJ[/tex]
The final temperature of the water is 676.164 °C and the specific work required is 1171.384 kilojoules per kilogram.
Let suppose that compression occurs quasi-statically, work is done on the closed system and enthalpy is increased. By First Law of Thermodynamics, we model compression process as following:
[tex]W_{in} + (U_{1} - U_{2}) + (P_{1}\cdot V_{1} - P_{2}\cdot V_{2}) = 0[/tex] (1)
Where:
[tex]W_{in}[/tex] - Compression work, in kilojoules. [tex]U_{1}[/tex], [tex]U_{2}[/tex] - Initial and final internal energies of the system, in kilojoules.[tex]P_{1}[/tex], [tex]P_{2}[/tex] - Initial and final pressures of the system, in kilopascals.[tex]V_{1}[/tex], [tex]V_{2}[/tex] - Initial and final volumes of the system, in cubic meters.By definition of enthalpy, in kilojoules per kilogram, and by dividing the resulting expression by the mass of the entire system, we have the following expression:
[tex]w_{in} = h_{2}-h_{1}[/tex] (2)
Where:
[tex]w_{in}[/tex] - Specific compression work, in kilojoules per kilogram.[tex]h_{1}[/tex], [tex]h_{2}[/tex] - Initial and final specific enthalpies, in kilojoules per kilogram.From steam tables we find that initial and final states of the water are represented by the following data:
Initial state
[tex]P = 70\,kPa[/tex], [tex]T = 100\,^{\circ}C[/tex], [tex]h = 2679.76\,\frac{kJ}{kg}[/tex], [tex]s = 7.56162\,\frac{kJ}{kg\cdot K}[/tex] (Superheated steam)
Final state
[tex]P = 4000\,kPa[/tex], [tex]T = 676.164\,^{\circ}C[/tex], [tex]h = 3851.144\,\frac{kJ}{kg}[/tex], [tex]s = 7.56162\,\frac{kJ}{kg}[/tex] (Superheated steam)
By (1) we have that the specific work required is:
[tex]w_{in} = 3851.144\,\frac{kJ}{kg} - 2679.76\,\frac{kJ}{kg}[/tex]
[tex]w_{in} = 1171.384\,\frac{kJ}{kg}[/tex]
The final temperature of the water is 676.164 °C and the specific work required is 1171.384 kilojoules per kilogram.
To learn more on closed systems, we kindly invite to check this verified question: https://brainly.com/question/3690180
Describe the role of C-S-H in providing strength for cement. Discuss which compounds produce C-S-H and why balancing the amounts of those compounds is important.
Answer:
Following are the solution to this question:
Explanation:
Whenever a chemical reaction occurs between water and cement the heat is released, and a [tex]CaOSiO_2H_2O[/tex] (C-S-H gel) gel constructs gel is also recognized as "tobermorite gel."
This one gel acts like a pack of gum and also has a cement quality, that holds its particles intact and therefore contributes to the overall compression mix. An increase in supply explicitly causes the movement in the outcome of power. C3S and C2S are both the compounds of Bouge that produce hydration C-S-H gel.
It mixture must be balanced as [tex]Ca(OH)_2[/tex] with C-S-H gel also is given as a byproduct. It [tex]Ca(OH)_2[/tex] , that cause sudden with sulphate and form [tex]CaSO_4[/tex] , is an unacceptable substance. Sulfate attack or later deterioration of its cement is caused by this [tex]CaSO_4[/tex] .
All C3S and C2S generate various amounts of C-S-H gel so, the required strength can be maintained without compromising on real term durability.
Tahir travel twice as far as ahmed, but onley one third as fast. Ahmed starts travel on tuesday at noon at point x to point z 300km, by 9:00pm. Tahir starts travel same day after 3hr of ahmed. In which time tahir reach at point z?
Answer:
6:00 pm the next day
Explanation:
Given that
Tahir traveled twice as far as Ahmed. We say,
Ahmed traveled a distance, D
Tahir would travel a distan, 2D
Tahir traveled 1/3 as fast as Ahmed, so we say
Ahmed traveled at a speed, S
Tahir would travel at a speed, S/3
If Ahmed starts travel on tuesday at noon at point x to point z 300km, by 9:00pm,
Time taken by Ahmed to travel is
9:00 pm - 12:00 pm = 9 hours
Ahmed, traveled 300 km in 9 hours, meaning he traveled at 33.3 km in an hour.
Speed, S that Ahmed traveled with is 33.3 km/h
Remember, we stated that Tahir travels at a speed of S/3, that is, The speed of Tahir is
33.3/3 = 11.1 km/h.
300 km would then be traveled in 300 km/11.1 km/h = 27 hours.
Tahir started traveling, 3 hours after Ahmed, that is 12:00 pm + 3:00 hrs = 3:00 pm, and if he's to spend 27 hours on the journey he would reach destination z at 6:00 pm the next day
how do the brushes control the amount of charging an alternator does
Explanation:
Think of brushes as a sliding contact.
In an alternator the brushes provide power to the field coil which is physically mounted on the rotating shaft. They provide this direct current through two slip rings.
By controlling the power flow to the field, the power output of the alternator can be controlled. A regulator circuit is used to control the field so that the output voltage is maintained to about 13.5 to 14.5 VDC.
FUN FACT: Many brush holders have a small holes near the brush exit. When you assemble the alternator you physically push the brushes all the way into their holder and then thread a small wire through these hole. After the alternator is assembled you can pull the wire out and the brushes will snap into position.
four subjects civil engineers need to study
Answer:
A civil engineering degree program applies mathematics and physical science to solve specific, real-world problems in commerce and industry. A strong civil engineering program typically emphasizes the practical use of geometry, trigonometry, and calculus in conjunction with physics, material science, and chemistry.
Explanation:
Hope this helps!! Please consider marking brainliest! Have a good one!!
What are the prefixes for 1, 10, 1000, 1,000,000, .1, .01, .001, .000001
Prefix Symbol Multiplier Exponential
yotta Y 1,000,000,000,000,000,000,000,000 1024
zetta Z 1,000,000,000,000,000,000,000 1021
exa E 1,000,000,000,000,000,000 1018
peta P 1,000,000,000,000,000 1015
tera T 1,000,000,000,000 1012
giga G 1,000,000,000 109
mega M 1,000,000 106
kilo k 1,000 103
hecto h 100 102
deca da 10 101
1 100
deci d 0.1 10¯1
centi c 0.01 10¯2
milli m 0.001 10¯3
micro µ 0.000001 10¯6
nano n 0.000000001 10¯9
pico p 0.000000000001 10¯12
femto f 0.000000000000001 10¯15
atto a 0.000000000000000001 10¯18
zepto z 0.000000000000000000001 10¯21
yocto y 0.000000000000000000000001 10¯24
Select one correct statement: A) Specific ions are necessary for metals and alloys.B) An environment that causes SCC of one alloy would also causes SCC of another alloy.C) As specific ions form a film on the metal surface, hence, those ions which form films may be adequate to cause SCC.
Answer:
option C
Explanation:
The correct statement is As specific ions form a film on the metal surface, hence those ions which form films may be adequate to cause SCC
other options are wrong as ; specific ions are not necessary for metals and alloys and also an environment causing SCC for an alloy might not cause SCC of another alloy found in the environment
what is the correct answer A, B, C, D
will give 35 points and brainiest
Which of the following devices is used to determine if an item is horizontal?
A. a level
B. a lever
C. a shank
D. a clamp
Answer:
B a lever because it can move up and down
Explanation:
Cody’s car accelerates from 0m/s to 45 m/s northward in 15 seconds. What is the acceleration of the car

Answer:
3 m/s²
Explanation:
Acceleration is calculated as :
a= Δv/ t
where ;
Δv = change in velocity
Δv = 45 - 0 = 45 m/s
t= 15 s
a= 45 /15
a= 3 m/s²
An automotive fuel has a molar composition of 85% ethanol (C2H5OH) and 15% octane (C8H18). For complete combustion in air, determine: (a) the molar air-fuel ratio and air-fuel ratio by mass. (b) the lower heating value, in kJ per kmol of fuel and in kJ per kg of fuel.(c) the higher heating value, in kJ per kmol of fuel and in kJ per kg of fuel. (d) the dew point temperature of the combustion products at 1 atm, in °C. Consider a reference temperature and pressure of 25°C, 1 atm.
Answer:
a) 1
b) 1813.96 MJ/kmol
c) 32.43 MJ/kg , 1980.39 MJ/Kmol
Explanation:
molar mass of ethanol (C2H5OH) = 46 g/mol
molar mass of octane (C8H18) = 114 g/mol
therefore the moles of ethanol and octane
ethanol = 0.85 / 46
octane = 0.15 / 114
a) determine the molar air-fuel ratio and air-fuel ratio by mass
attached below
mass of air / mass of fuel = 12.17 / 1 = 12.17
b ) Determine the lower heating value
LHV of ( C2H5OH) = 26.8 * 46 = 1232.8 MJ/kmol
LHV of (C8H18). = 44.8 mj/kg * 114 kg/kmol = 5107.2 MJ/Kmol
LHV ( MJ/kmol) for fuel mixture = 0.85 * 1232.8 + 0.15 * 5107.2 = 1813.96 MJ/kmol
c) Determine higher heating value ( HHV )
HHV of (C2H5OH) = 29.7 * 46 = 1366.2 MJ/kmol
HHV of C8H18 = 47.9 MJ/kg * 114 = 5460.6 MJ/kmol
HHV in MJ/kg = 0.85 * 29.7 + 0.15 * 47.9 = 32.43 MJ/kg
HHV in MJ /kmol = 0.85 * 1366.2 + 0.15 * 5460.8 = 1980.39 MJ/Kmol
List the three main phases of photo interpretation in photogrammetry
Answer:
Stages of Interpretation and Mapping
Selection of photographs. Whenever possible, all photographs of a site or small area should be assessed for fitness of purpose. ...
Control points. A good spread of control points on a photograph is vital to establish the exact location or size of features. ...
Transformation.
Explanation:
Select a Goulds 3196 pump to operate at 3560 rpm to deliver 500 gpm of water at a head of 250 ft. What impeller diameter should be installed in the pump
Answer:
Impeller diameter should be 0.02 meter
Explanation:
The Impeller diameter is a parameter with a circular design of a high speed pump. The performance of the pump depends on this parameter.
As per the given data
Speed of pump = 3,560 rpm
Rate of water flow = 500 gpm = 0.0005 m^3/minutes
Size of head = 250 ft = 250 ft x 0.3048 m/ft = 76.2 m
The impeller diameter can be calculated using following formula
Impeller diameter =0.1 x [tex]\sqrt{Water flow rate X 60}[/tex]
Impeller diameter =0.1 x [tex]\sqrt{0.0005 X 60}[/tex]
Impeller diameter =0.1 x [tex]\sqrt{0.03}[/tex]
Impeller diameter = 0.1 x 0.1732
Impeller diameter = 0.01732
Impeller diameter = 0.02 m
A rod with a length of L has to be made to carry load F. You need to select from the following alloys: Material Density g/cc Yield Strength, MPa AI 7075 2.81 503 AISI 4340/SAE 7.85 1160 Mg-ZK61 1.83 195 Ti8Al1Mo1V 4.37 570 Which one will have the lightest weight
Answer:
AI 7075
Explanation:
Material Density g/cc Yield strength
AI 7075 2.81 503
AISI 4340/SAE 7.85 1160
Mg-ZK61 1.83 195
Ti8A|1Mo1V 4.37 570
Determine the alloy with the lightest weight using this relationship
weight ∝ ( S / E )
E = yield strength
S = density
for AI 7075 = 2.81 / 503 = 0.00558648for AISI 4340/SAE = 7.85 / 1160 = 0.00676724for Mg-ZK61 = 1.83 / 195 = 0.00938462for Ti8A|1Mo1V = 4.37 / 570 = 0.00766667from the above calculation the alloy with the lightest weight is ;
AI 7075
What is different about residential construction on the local level from residential construction on the national level?
Answer:
The difference lies in the coverage of the construction. While local level construction focuses on the local area, national level construction has a nation-wide coverage.
Explanation:
Residential construction concentrates on the construction of residential buildings that have sleeping accommodations. Such constructions are opposed to the construction of other buildings that are meant for commercial uses as they lack sleeping accommodations. The federal, state, and local governments can embark on the construction of residential quarters for their residents. The constructions are also funded at the given level. When it is locally funded, the construction is meant to satisfy specific local needs. The constructions by the federal government consider the needs of many localities, and may not meet specific local needs.
Answer: A Residential construction is local in its effects even though those effects have a national impact.
Explanation:
A steam power plant with a power output of 230 MW consumes coal at a rate of 60 tons/h. If the heating value of the coal is 30,000 kJ/kg, determine the overall efficiency of this plant.
Answer:
[tex]\eta =46\%[/tex]
Explanation:
Hello!
In this case, we compute the heat output from coal, given its heating value and the mass flow:
[tex]Q_H=60\frac{tons}{h}*\frac{1000kg}{1ton}*\frac{1h}{3600s}*\frac{30,000kJ}{kg}\\\\Q_H=500,000\frac{kJ}{s}*\frac{1MJ}{1000J} =500MW[/tex]
Next, since the work done by the power plant is 230 MW, we compute the efficiency as shown below:
[tex]\eta =\frac{230MW}{500MW}*100\% \\\\\eta =46\%[/tex]
Best regards!
The velocity in a channel that is 3 m deep is 1 m/s. What is the Froude number in a 1/6 scale model of that channel that satisfies dynamic similarity?a. 1.b. 0.45.c. 0.18.d. 5.4.e. 0.08.
Answer:
c. 0.18
Explanation:
The Formula for Froude Number is given as follows:
Froude No. = Inertial Forces/Gravity Forces
Froude No. = v/√(gD)
where,
v = velocity = 1 m/s
g = 9.8 m/s²
D = Depth of channel = 3 m
Therefore,
Froude No. = (1 m/s)/√[(9.8 m/s²)(3 m)]
Froude No. = 0.18
hence, the correct option will be:
c. 0.18
35 points and brainiest is it A, B, C, D
Which of the following nails would most likely be used in securing a delicate, decorative piece of thin wood trim to a cabinet face?
A. 2d
B. 10d
C. 60d
D. 100d
Answer:
c thereeeeeeeeeeeeeeeeee
Refrigerant-134a enters an adiabatic compressor as saturated vapor at 160 kPa at a rate of 2.4 m3/min and is compressed to a pressure of 900 kPa. Determine the minimum power that must be supplied to the compressor. Use the tables for R-134a
Answer:
11.65kWExplanation:
Step one:
given data
from the table for R-134a
For the given pressure state the following data were extracted.
s=0.94202kJ/kg.K
h1=241.14kJ/kg
∝1=0.12355m^3/kg
By interpolation, the final enthalpy and pressure with data from the table of R-134a
h2=277.12kJ/kg
The minimum power output is then determined from the energy balance
W=m(h2-h1)
W=V1/∝1(h2-h1)
W=2.4/60/0.12355(277.12-241.14)
W=0.04/0.12355(35.98)
W=0.3237(35.98)
W=11.65kW Approx.
The minimum power output of the compressor is 11.65kW
35 points and brainiest. A, B, C, D
Which of the following identifies what carbide-tipped bits, lines on machine bolts, and lock washers all have in common?
A. All are very expensive items.
B. All are very recent inventions.
C. All are rather outdated inventions.
D. All provide an added level of strength.
Answer:c
Explanation:
What is least conducive to a rich tradition of master craftsmanship?
A. A reliance on mass production of necessary parts.
B. A demand for unique features.
C. A way for passing on knowledge of craft.
D. A respect for high craftsmanship as a kind of art.
/~\ The correct answer is:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
B. A demand for unique features.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I hope this helps! /~\
Answer:
A. A reliance on mass production of necessary parts.
Explanation:
Took the test
The shape of the wood beam is a rectangle. In a paragraph explain the tradeoffs an engineer would make in selecting a wood with a rectangle shape versus manufactured beams with other stronger but lighter weight shapes.
Answer:
Wood is heavy
Explanation:
The article provides information by using a list. What does it list? A. Thanksgiving food B. places where clams can be found C. birds served at the first Thanksgiving D. four men who went on a "fowling" mission
Answer:
C
Explanation: