Question:
In a typical transmission line, the current I is very small and the voltage V is very large. A unit length of the line has resistance R.
For a power line that supplies power to 10 000 households, we can conclude that
a) IV < I²R
b) I²R = 0
c) IV = I²R
d) IV > I²R
e) I = V/R
Answer:
d) IV > I²R
Explanation:
In a typical transmission line, the current I is very small and the voltage V is very high as to minimize the I²R losses in the transmission line.
The power delivered to households is given by
P = IV
The losses in the transmission line are given by
Ploss = I²R
Therefore, the relation IV > I²R holds true, the power delivered to the consumers is always greater than the power lost in the transmission line.
Moreover, losses cannot be more than the power delivered. Losses cannot be zero since the transmission line has some resistance. The power delivered to the consumers is always greater than the power lost in the transmission.
Isolation amplifiers, also known as "followers" of "buffers", are characterized by high- impedance inputs and low-impedance outputs. In your own words, describe exactly what that means and suggest an application where it could be useful
Answer:
Buffers in electrical systems are amplifiers that prevent input voltage from being affected by whatever curent the load draws
Explanation:
The input and output parts of the circuit are isolated. By having high-impedance(following ohms law, V=IR) very small current is drawn by the amplifier circuit. The output and input voltages are same. However, the output impedance is very low. In this way power losses are minimized and vlotage levels are maintained for the load
They are useful where a measurement of small signal is required in the presence of high voltage.
They are also used in multi-stage filters to isolate one stage from another
You are to design a digital communication system to transmit four multiplexed analog signals with bandwidths of 1200 Hz, 900 Hz, 300 Hz and 1500 Hz, respectively. Each analog signal is to be sampled at its own respective Nyquist rates and encoded using linear PCM. The maximum tolerable error for each sample is 1% of the signal's peak voltage (Vo).
(a) What is the minimum PCM word size (bits per sample) required?
(b) What is the minimum transmitted bit rate for each of the sampled signals?
(c) Assume the signals are multiplexed on a sample-by-sample basis (each PCM sample is considered a unit not to be divided between frames). If 10 bits per frame are added for synchronization, what is the minimum frame size required (bits)? How many samples from each signal are included in each frame?
(d) What is the transmitted frame rate of the frame defined in part (c) in frames per second? What is the overall transmitted bit rate of the multiplexed digital communication system (bits per second)?
Answer and Explanation:
The answer is attached below
A 600-ha farmland receives annual rainfall of 2500 mm. There is a river flowing through the farmland with an inflow rate of 5 m3/s and outflow rate of 4 m3/s. The annual water storage is the farmland increases by 2.5 x 106 m3. Based on the hydrologic budget equation, determine the annual evapotranspiration amount in mm. (1 ha
Answer:
E = 7333.33 mm
Explanation:
The annual evapotranspiration (E) amount can be calculated using the water budget equation:
[tex] P*A + Q_{in}*\Delta t = E*A + \Delta S + Q_{out}*\Delta t [/tex] (1)
Where:
P: is the precipitation = 2500 mm,
Q(in): is the water flow into the river of the farmland = 5 m³/s,
ΔS: is the change in water storage = 2.5x10⁶ m³,
Q(out): is the water flow out of the river of the farmland = 4 m³/s.
Δt: is the time interval = 1 year = 3.15x10⁷ s
A: is the surface area of the farmland = 6.0x10⁶ m²
Solving equation (1) for ET we have:
[tex] E = \frac{P*A + Q_{in}*\Delta t - \Delta S - Q_{out}*\Delta t}{A} [/tex]
[tex] E = \frac{2.5 m \cdot 6.0 \cdot 10^{6} m^{2} + 5 m^{3}/s \cdot 3.15 \cdot 10^{7} s - 2.5 \cdot 10^{6} m^{3} - 4 m^{3}/s \cdot 3.15 \cdot 10^{7} s}{6.0\cdot 10^{6} m^{2}} [/tex]
[tex] E = 7333.33 mm [/tex]
Therefore, the annual evapotranspiration amount is 7333.33 mm.
I hope it helps you!
The annual evapotranspiration amount can be calculated using the hydrologic budget equation, by arranging known values of rainfall, inflow and outflow rates, and increase in water storage. This gives us the evapotranspiration amount in cubic meters which can be converted into depth (in mm) by dividing by the total land area.
Explanation:The annual evapotranspiration amount can be calculated using the concept of the hydrologic budget equation, which states that the change in storage equals the sum of inputs minus the sum of outputs. In this scenario, rainfall and river inflow are the water inputs while evapotranspiration and river outflow are the water outputs. Given that the increase in water storage, rainfall, and river flow rates are known, we can rearrange the equation to find the evapotranspiration.
It results in:
Evapotranspiration (in m3) = Rainfall + Inflow - Outflow - Increase in Storage
Substituting the given values:
Evapotranspiration (in m3) = (2500 mm * 600 ha * 10,000 m2/ha * 1m/1000mm) + (5 m3/s * 31,536,000 s) - (4 m3/s * 31,536,000 s) - 2.5 * 106 m3;
To convert evapotranspiration volume to depth (in mm), we divide by the total land area:
Evapotranspiration (in mm) = Evapotranspiration (in m3) / (600ha * 10,000 m2/ha * 1mm/1m)
After computing the above equations, we arrive at the annual evapotranspiration amount in mm.
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An adiabatic closed system is raised 100 m at a location where the gravitational acceleration is 9.8 m/s2. What Is the specific energy change of this system in kJ/kg?
Answer: 0.98kJ/kg
Explanation: for a kilogram mass of this system, raising the system at a height h gives it a potential energy of the magnitude gh,
Where g is gravitational acceleration,
and h is the height difference.
This system will have an energy change of
PE = 100*9.8 = 980 J/kg
This becomes 980/1000 kJ/kg
= 0.98kJ/kg
2 samples of water of equal volume are put into dishes and kept at room temp for several days. the water in the first dish is completely vaporized after 2.8 days while the water in the second dish takes 8.3 days to completely evaporate. What can you conclude about the two dishes
Answer:
Vaporization is the process by which a substance changes from its solid or liquid state to a gaseous state.
Since both liquids are of the same volume and are placed under the same temperature condition, for them to not to vaporize at the same time, they must have been in different containers.
For vaporization to take place, the volume of liquid, amount of air exposure and area of the surface must be considered.
Maybe the first liquid was in a dish which has a large opening, thereby exposing a large amount which can make water to evaporate faster, whereas the second liquid was somehow enclosed (in a deeper dish).
Write a mechanism for the first step of this reaction using curved arrows to show electron reorganization. Consult the arrow-pushing instructions for the convention on regiospecific electrophilic attack on a double bond.
Answer:
1. Alkenes Can Be Nucleophiles! But How Do We Draw The Curved Electron-Pushing Arrows?
2. The Conventional Approach For Drawing Electron-Pushing Curved.
3. Arrows In Alkene Addition Reactions Is Slightly Ambiguous Modified Electron-Pushing Arrow Convention #1: “Bouncy” Arrows.
4. Modified Curved Arrow Convention #2: “Pre-bonds”.
Explanation:
1. Alkenes Can Be Nucleophiles! But How Do We Draw The Curved Electron-Pushing Arrows?
Alkenes are a lot more exciting than they’re often given credit for. That means that given a sufficiently frisky electrophile, they can donate their pair of π electrons to form a new sigma bond.
Like this!
However, there’s one little problem here. See that curved arrow? What does it really mean? If you weren’t given the product, would you be able to draw it, given that curved arrow?
See the problem here: Which atom of the alkene is actually forming the bond to hydrogen? When we were dealing with lone pairs, it was easy: atoms clearly “own” their lone pairs, and we can tell exactly which atom is forming a bond to which. With alkenes, it’s different: since they “share” that pair of electrons, we’re going to have to somehow show which atom gets the new atom and which is left behind as a carbocation.
2. The Conventional Approach For Drawing Electron-Pushing Curved Arrows In Alkene Addition Reactions Is Slightly Ambiguous
Here’s the conventional way it’s done. If we want to show the bottom carbon forming the bond, the usual way to do this is to draw this loop like this, to show the “path” of the electrons coming in an arc from this direction. The carbon on the alkene “closest” to the hydrogen is the one that ends up bonded to it.
Similarly, if we wanted to show the left carbon forming the bond, we’d “arc” the bond like this:
One problem with this: it’s kind of a kludge. The curved arrow notation is limited in that all we can really do is decide where the tail should go (at the π bond, obviously) and where the head should go (to form the new bond). But the question of which carbon forms the bond is still ambiguous.
And if there’s one thing organic chemists hate, it’s ambiguity.
Give me clear definitions or give me death!
To try and deal with this issue, organic chemists have come up with two potential solutions. They’re worth looking at if you’re finding this issue confusing.
3. Modified Electron-Pushing Arrow Convention #1: “Bouncy” Arrows.
Instead of showing the curved arrow as a big sweeping arc, one solution is to put an extra bounce into the arrow. The idea here is that we’re showing the pair of electrons travelling to the carbon in question, and from there moving on to form the new sigma bond. No more ambiguity here. [Literature reference]
This solves the ambiguity problem at the expense of putting in an extra hump in the arrow. Although it doesn’t seem like a big deal, the extra bounce has likely been the reason why this convention hasn’t taken off. However well intentioned, the trouble with a convention like this is humanity’s natural tendency towards laziness: taking the time to consistently draw an extra hump into the arrow – even if it takes only 5 seconds – represents extra work that is skipped unless absolutely necessary. Behavioral change is very difficult.
4. Modified Curved Arrow Convention #2: “Pre-bonds”.
Another way of dealing with this is to insert the equivalent of “training wheels” into our curved arrows. Since the curved arrow is itself ambiguous, to clarify things we put in a dashed line that precisely delineates where the new bond is forming. Then, we draw the arrow with the tail coming from the electron source (the π bond) and the head going to the new bond. We can put the arrow right on the dashed line itself. This has the advantage of not modifying the curved arrow convention itself, just adding in an optional “guide” that makes its application more clear. [For an application of this technique I recommend checking out Dr. Peter Wepplo’s blog, where I first found this convention used]
dotted line convention for alkene addition resolves ambiguity
If you find yourself confused following the movement of electrons in the reactions of alkenes with electrophiles, these supplementary conventions might be of use to you.
Personally, even though conventional curved arrows suffer from a bit of ambiguity, that’s generally not enough to make me stop using them. YMMV.
In the next post we’ll resume our regularly scheduled program on alkenes and carbocations.
A 200-gr (7000 gr = 1 lb) bullet goes from rest to 3300 ft/s in 0.0011 s. Determine the magnitude of the impulse imparted to the bullet during the given time interval. In addition, determine the magnitude of the average force acting on the bullet.
The magnitude of the impulse imparted to the bullet is 2.932 lb s. The magnitude of the average force acting on the bullet during the given time interval is 2666 lb.
Calculate the Impulse
Impulse is defined as the change in momentum of an object. It is given by the equation:
[tex]\[ \text{Impulse} = \Delta p = m \Delta v \][/tex]
Conversion factor for pound to slug (since force in pounds and velocity in ft/s, mass should be in slugs, where 1 slug = 32.174 lb):
[tex]\[ m \text{ (in slugs)} = \frac{0.02857 \text{ lb}}{32.174 \text{ lb/slug}}\\ = 0.000888 \text{ slugs} \][/tex]
[tex]\[ \text{Impulse} = m \Delta v = 0.000888 \text{ slugs} \times 3300 \text{ ft/s} \\= 2.9324 \text{ slug ft/s} \][/tex]
The impulse imparted to the bullet is:
[tex]\[ \text{Impulse} = 2.9324 \text{ lb s} \][/tex]
Calculate the Average Force
The average force can be calculated using the formula:
[tex]\[ F_{avg} = \frac{\Delta p}{\Delta t} \][/tex]
Given:
Time interval, [tex]\( \Delta t = 0.0011 \text{ s} \).[/tex]
[tex]\[ F_{avg} = \frac{2.9324 \text{ lb s}}{0.0011 \text{ s}} \\= 2665.82 \text{ lb} \][/tex]
An insulated piston-cylinder device contains 4 L of saturated liquid water at a constant pressure of 175 kPa. Water is stirred by a paddle wheel while a current of 7 A flows for 45 min through a resistor placed in the water. If one-half of the liquid is evaporated during this constant-pressure process and the paddle-wheel work amounts to 300 kJ, determine the voltage of the source.
Answer:
The voltage of the source is 207.5 V
Explanation:
Given:
Volume of the water V = 4 L
Pressure P = 175 KPa
Dryness fraction x2 = 0.5
The current I = 7 Amp
Time T = 45 min
The paddle-wheel work Wpw = 300 KJ
Obs: Assuming the kinetic and potential energy changes, thermal energy stored in the cylinder and cylinder is well insulated thus heat transfer are negligible
1 KJ/s = 1000 VA
Energy Balance
Ein - Eout = ΔEsys
We,in + Wpw, in - Wout = ΔU
IVΔT + Wpw, in = ΔH = m(h2 - h1)
Using the steam table (A-5) at P = 175 KPa, x1 = 0
v1 = vf = 0.001057 [tex]m^{3}/ Kg[/tex]
h1 = h2 = 487.01 [tex]\frac{KJ}{Kg}[/tex]
Using the steam table (A-5) at P = 175 KPa, x1 = 0.5
h2 = hf + x2 (hg - hf) = 487.1 + 0.5 * (2700.2 - 487.1) = 1593.65 [tex]\frac{KJ}{Kg}[/tex]
The mass of the water is
m = V/v1
m = 0.004/0.001057 = 3.784 Kg
The voltage is
V = [tex]\frac{m(h2 - h1) - Wpw,in}{I (delta)t}\\[/tex]
V = [tex]\frac{3.784 * (1593.65 - 478.1) - 300}{7 * (45 * 60)}[/tex] = 0.207 * 1000 = 207.5 V
The final temperature of the water is 75°C.
Explanation:In this problem, we are given the initial and final volumes of the gas, and we need to find the final temperature of the water. Considering that the process is isothermal and all the heat goes into the water, we can use the formula:
(initial volume * initial temperature) = (final volume * final temperature)
Given that the initial volume is 3 L and the final volume is 18 L, and the initial temperature of the water is 25°C, we can calculate the final temperature:
(3 L * 25°C) = (18 L * final temperature)
Simplifying this equation, we find that the final temperature of the water is 75°C.
A cylindrical specimen of cold-worked steel has a Brinell hardness of 250.(a) Estimate its ductility in percent elongation.(b) If the specimen remained cylindrical during deformation and its original radius was 5 mm (0.20 in.), determine its radius after deformation.
Answer:
A) Ductility = 11% EL
B) Radius after deformation = 4.27 mm
Explanation:
A) From equations in steel test,
Tensile Strength (Ts) = 3.45 x HB
Where HB is brinell hardness;
Thus, Ts = 3.45 x 250 = 862MPa
From image 1 attached below, for steel at Tensile strength of 862 MPa, %CW = 27%.
Also, from image 2,at CW of 27%,
Ductility is approximately, 11% EL
B) Now we know that formula for %CW is;
%CW = (Ao - Ad)/(Ao)
Where Ao is area with initial radius and Ad is area deformation.
Thus;
%CW = [[π(ro)² - π(rd)²] /π(ro)²] x 100
%CW = [1 - (rd)²/(ro)²]
1 - (%CW/100) = (rd)²/(ro)²
So;
(rd)²[1 - (%CW/100)] = (ro)²
So putting the values as gotten initially ;
(ro)² = 5²([1 - (27/100)]
(ro)² = 25 - 6.75
(ro) ² = 18.25
ro = √18.25
So ro = 4.27 mm
Description: Write a function that takes in a list of numbers and a list of indices. Note that indexList may not only contain valid indices. The function should keep track of the number and type of errors that occur. Specifically, it should account for IndexError and TypeError . It should return the average of all the numbers at valid indices and a dictionary containing the number and type of errors together in a tuple. errorDict should be formatted as follow
Answer:
Python code is explained below
Explanation:
average , count, indexerror, typeerror variables are initialised to 0
Then, for loop is used to traverse the indexlist, if type is not right, typeerror is incremented, else if index is not right, indexerror is incremented, otherwise, count is incremented, and the number is added to average.
At last, average variable which contains the sum of numbers is divided by count to get average.
Here is the code:
def error_finder(numList, indexList):
average = 0
count = 0
indexerror = 0
typeerror = 0
for i in range(len(indexList)):
if type(indexList[i])==int:
if indexList[i]>=len(numList) or i<0:
indexerror = indexerror + 1
else:
average = average + numList[indexList[i]]
count = count+1
else:
typeerror = typeerror + 1
d = {"IndexError": indexerror, "TypeError":typeerror}
average = average/count
return(average, d)
print(error_finder([4, 5, 1, 7, 2, 3, 6], [0, "4", (1, ), 18, "", 3, 5.0, 7.0, {}, 20]))
One kilogram of a contaminant is spilled at a point in a 4m deep reservoir and is instantaneously mixed over the entire depth. (a) If the diffusion coefficients in the N-S and E-W directions are 5 and 10 m2 /s, respectively, calculate the concentration as a function of time at locations 100m north and 100m east of the spill. (b) What is the concentration at the spill location after 5 minutes
Answer:
0.028 kg per Seconds; 8.4
Explanation:
N-S, 4 x 100 = 400 m^2, concentration 5/400= 0.0125 kg/s
E-W 4 x 100 =400 m^2 , => 10/400 =0.025 kg/s
(0.0125^2 + 0.025^2)^(1/2) =0.028 kg/s
in 5 minutes = 5 x 60 x 0.028 =8.4
A 60-g projectile traveling at 605 m/s strikes and becomes embedded in the 54-kg block, which is initially stationary. Compute the energy lost during the impact. Express your answer as an absolute value |ΔE| and as a percentage
Kinetic energy lost in collision is 1097.95 J
Explanation:
Given,
Mass, [tex]m_{1}[/tex]= 60 g = 0.006 kg
Speed, [tex]v_{1}[/tex] = 605 m/s
[tex]m_{2}[/tex] = 54 kg
[tex]v_{2}[/tex]= 0
Kinetic energy lost, K×E = ?
During collision, momentum is conserved.
So,
[tex]m1v1 + m2v2 = (m1 + m2)v\\\\0.006 X 605 + 54 X 0 = (0.006 + 54) v\\\\v = \frac{3.63}{54.006}\\ \\v = 0.067m/s[/tex]
Before collision, the kinetic energy is
[tex]\frac{1}{2}* m1 * (v1)^2 + \frac{1}{2} * m2 * (v2)^2[/tex]
[tex]=\frac{1}{2} X 0.006 X (605)^2 + 0\\\\= 1098.075J[/tex]
Therefore, kinetic energy before collision is 1098 J
Kinetic energy after collision:
[tex]\frac{1}{2}* (m1+m2) * (v)^2 + KE(lost)[/tex]
By plugging in the values, we get
[tex]\frac{1}{2} * (0.006 + 54) * (0.067)^2 + KE(lost)[/tex]
[tex]0.1212J + KE(lost)[/tex]
Since,
initial Kinetic energy = Final kinetic energy
1098.075 J = 0.1212 J + K×E(lost)
K×E(lost) = 1098.075 J - 0.121 J
K×E(lost) = 1097.95 J
Therefore, kinetic energy lost in collision is 1097.95 J
Two physical properties that have a major influence on the cracking of workpieces, tools, or dies during thermal cycling are thermal conductivity and thermal expansion.Explain why.
Answer:
Explanation:
It is generally known that the thermal stresses developed during thermal cycle results into cracking, and these thermal stresses are due to temperature gradients .
Stresses will be equivalently lower for a particular temperature gradient when the thermal expansion is low.
It also known that there will be a reduction in the temperature gradient if the thermal conductivity is high, as heat is dissipated faster and more equally and with it, as well as when deformation takes place due to thermal stresses, cracking occurs but if the ductility is high, more deformation will be allowed without cracking and thus reduces the tendency for cracking.
Thermal expansion and conductivity influence cracking during thermal cycling because materials expand or contract at different rates causing stress. Differences in these properties between bonded materials or different parts of a structure can lead to cracks. Understanding these properties is important in designing materials to minimize thermal stress.
Explanation:The two physical properties that have a major influence on the cracking of workpieces, tools, or dies during thermal cycling are thermal conductivity and thermal expansion. Thermal expansion occurs due to the tendency of a material to change in volume in response to a change in temperature. When different parts of a workpiece, or different materials bonded together, have different thermal expansion coefficients or varied thermal conductivities, thermal stress can result as the materials expand or contract at different rates. This stress leads to the formation of cracks, especially if the material is rigid and cannot accommodate the stress through deformation.
For example, metal implants in the body may need replacement because of the lack of bonding between metal and bone due to different expansion coefficients. Similarly, the expansion of fillings in teeth can be different from that of tooth enamel, causing discomfort or damage. The understanding of thermal expansion and conductivity is critical in designing materials and structures, such as railroad tracks and roadways with adequate expansion joints to prevent buckling, or using materials like Pyrex for cooking pans to minimize cracking from thermal stress.
Find the value of R2 required if vs = 18 V , R1 = 50 kΩ , and the desired no-load output voltage is vo = 6 VPart b)Several different loads are going to be used with the voltage divider from Part A. If the load resistances are 300 kΩ , 200 kΩ , and 100 kΩ , what is the output voltage that is the most different from the design output voltage vo = 6 V ?part c)The circuit designer wants to change the values of R1 and R2 so that the design output voltage vo = 6 V is achieved when the load resistance is RL = 200 kΩ rather than at no-load. The actual output voltage must not drop below 5.4 V when RL = 100 kΩ . What is the smallest resistor value that can be used forR1?
Answer:
Explanation:
Check attachment for solution
a. The value of R2 required for the desired no-load output voltage R2 = 10 kΩ
b. The most different output voltage is 5.8 V, which occurs when the load resistance is 300 kΩ.
c. The smallest resistor value that can be used for R1 is 45 kΩ.
Part A:
To find the value of R2 required for the desired no-load output voltage, we can use the following voltage divider equation:
vo = vs * R2 / (R1 + R2)
Substituting in the known values, we get:
6 V = 18 V * R2 / (50 kΩ + R2)
Solving for R2, we get:
R2 = 18 V * 6 V - 6 V * 50 kΩ / 6 V - 18 V
R2 = 10 kΩ
Part B:
To find the output voltage that is the most different from the design output voltage, we need to calculate the output voltage for each load resistance. We can use the following voltage divider equation:
vo = vs * (R2 / (R1 + R2) || RL)
Substituting in the known values for each load resistance, we get:
vo (RL = 300 kΩ) = 18 V * (10 kΩ / (50 kΩ + 10 kΩ) || 300 kΩ)
vo (RL = 300 kΩ) = 5.8 V
vo (RL = 200 kΩ) = 18 V * (10 kΩ / (50 kΩ + 10 kΩ) || 200 kΩ)
vo (RL = 200 kΩ) = 7.2 V
vo (RL = 100 kΩ) = 18 V * (10 kΩ / (50 kΩ + 10 kΩ) || 100 kΩ)
vo (RL = 100 kΩ) = 8.6 V
Therefore, the output voltage that is the most different from the design output voltage is 5.8 V, which occurs when the load resistance is 300 kΩ.
Part C:
To change the values of R1 and R2 so that the design output voltage vo = 6 V is achieved when the load resistance is RL = 200 kΩ rather than at no-load, we can use the following voltage divider equation:
vo = vs * R2 / (R1 + R2)
Substituting in the known values, we get:
6 V = 18 V * R2 / (R1 + 200 kΩ)
Solving for R2, we get:
R2 = 30 kΩ
Next, we need to calculate the value of R1 to ensure that the actual output voltage does not drop below 5.4 V when RL = 100 kΩ. We can use the following voltage divider equation:
vo = vs * (R2 / (R1 + R2) || RL)
Substituting in the known values, we get:
5.4 V = 18 V * (30 kΩ / (R1 + 30 kΩ) || 100 kΩ)
Solving for R1, we get:
R1 = 45 kΩ
Therefore, the smallest resistor value that can be used for R1 is 45 kΩ.
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A cubical picnic chest of length 0.5 m, constructed of sheet styrofoam of thickness 0.025 m, contains ice at 0\[Degree]C. The thermal conductivity of the styrofoam is 0.035 W/(m K) and the ambient temperature is 25 \[Degree]C. If the resistances to convective heat flow are negligible, calculate the rate at which the ice in the chest melts in units of kg/hour. The latent heat of melting of ice is 3.34 10^5 J/kg.
Answer:
Rate of heat transfer is 0.56592 kg/hour
Explanation:
Q = kA(T2 - T1)/t
Q is rate of heat transfer in Watts or Joules per second
k is thermal conductivity of the styrofoam = 0.035 W/(mK)
A is area of the cubical picnic chest = 6L^2 = 6(0.5)^2 = 6×0.25 = 1.5 m^2
T1 is initial temperature of ice = 0 °C = 0+273 = 273 K
T2 is temperature of the styrofoam = 25 °C = 25+273 = 298 K
t is thickness of styrofoam = 0.025 m
Q = 0.035×1.5(298-273)/0.025 = 1.3125/0.025 = 52.5 W = 52.5 J/s
Mass flow rate = rate of heat transfer ÷ latent heat of melting of ice = 52.5 J/s ÷ 3.34×10^ 5 J/kg = 1.572×10^-4 kg/s = 1.572×10^-4 kg/s × 3600 s/1 hr = 0.56592 kg/hr
The statements in the file main.cpp are in incorrect order.
Rearrange the statements so that they prompt the user to input:
The shape type (rectangle, circle, or cylinder)
The appropriate dimension of the shape.
Note: For grading purposes place the cylinder height statement before the radius statement.
The C++ program then outputs the following information about the shape:
For a rectangle, it outputs the area and perimeter
For a circle, it outputs the area and circumference
For a cylinder, it outputs the volume and surface area.
After rearranging the statements, your program should be properly indented.
Here is the code out-of-order:
using namespace std;
#include
int main()
{
string shape;
double height;
#include
cout << "Enter the shape type: (rectangle, circle, cylinder) ";
cin >> shape;
cout << endl;
if (shape == "rectangle")
{
cout << "Area of the circle = "
<< PI * pow(radius, 2.0) << endl;
cout << "Circumference of the circle: "
<< 2 * PI * radius << endl;
cout << "Enter the height of the cylinder: ";
cin >> height;
cout << endl;
cout << "Enter the width of the rectangle: ";
cin >> width;
cout << endl;
cout << "Perimeter of the rectangle = "
<< 2 * (length + width) << endl;
double width;
}
cout << "Surface area of the cylinder: "
<< 2 * PI * radius * height + 2 * PI * pow(radius, 2.0)
<< endl;
}
else if (shape == "circle")
{
cout << "Enter the radius of the circle: ";
cin >> radius;
cout << endl;
cout << "Volume of the cylinder = "
<< PI * pow(radius, 2.0)* height << endl;
double length;
}
return 0;
else if (shape == "cylinder")
{
double radius;
cout << "Enter the length of the rectangle: ";
cin >> length;
cout << endl;
#include
cout << "Enter the radius of the base of the cylinder: ";
cin >> radius;
cout << endl;
const double PI = 3.1416;
cout << "Area of the rectangle = "
<< length * width << endl;
else
cout << "The program does not handle " << shape << endl;
cout << fixed << showpoint << setprecision(2);
#include
In the rearranged code, the statements are placed in the correct order to prompt the user for input of the shape type and appropriate dimensions.
```cpp
#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main()
{
string shape;
double height, radius, width, length;
const double PI = 3.1416;
cout << "Enter the shape type: (rectangle, circle, cylinder) ";
cin >> shape;
cout << endl;
if (shape == "rectangle")
{
cout << "Enter the width of the rectangle: ";
cin >> width;
cout << endl;
cout << "Enter the length of the rectangle: ";
cin >> length;
cout << endl;
cout << "Area of the rectangle = "
<< length * width << endl;
cout << "Perimeter of the rectangle = "
<< 2 * (length + width) << endl;
}
else if (shape == "circle")
{
cout << "Enter the radius of the circle: ";
cin >> radius;
cout << endl;
cout << "Area of the circle = "
<< PI * pow(radius, 2.0) << endl;
cout << "Circumference of the circle: "
<< 2 * PI * radius << endl;
}
else if (shape == "cylinder")
{
cout << "Enter the height of the cylinder: ";
cin >> height;
cout << endl;
cout << "Enter the radius of the base of the cylinder: ";
cin >> radius;
cout << endl;
cout << "Volume of the cylinder = "
<< PI * pow(radius, 2.0) * height << endl;
cout << "Surface area of the cylinder: "
<< 2 * PI * radius * height + 2 * PI * pow(radius, 2.0) << endl;
}
else
cout << "The program does not handle " << shape << endl;
cout << fixed << showpoint << setprecision(2);
return 0;
}
```
In the rearranged code, the statements are placed in the correct order to prompt the user for input of the shape type and appropriate dimensions. Depending on the shape selected, the program computes and outputs the corresponding area, perimeter, circumference, volume, and surface area. The code is properly indented for readability.
According to Moore and Marra's (2005) case study, which observed two online courses, students in the first course implemented a constructive argumentation approach while students in second course had less structure for their postings. As they stated, when instructors create online discussion board activities, they must answer at least two questions. These questions are: "What is the objective of the discussions?" And "How important are online discussions in comparison to the other activities that students will perform?" According to their findings, the discussion activities that were designed based on the answers to these questions can influence the quality and quantity of interactions (Moore & Marra, 2005).
Your question is incomplete, please let me assume this to be your complete question;
ORIGINAL SOURCE:
When instructors are creating discussion board activities for online courses, at least two questions must be answered. First, what is the objective of the discussions? Different objectives might be to create a "social presence" among students so that they do not feel isolated, to ask questions regarding assignments or topics, or to determine if students understand a topic by having them analyze and evaluate contextual situations. Based on the response to this question, different rules might be implemented to focus on the quality of the interaction more so than the quantity. The second question is, how important is online discussions in comparison to the other activities that students will perform? This question alludes to the amount of participation that instructors expect from students in online discussions along with the other required activities for the course. If a small percentage of student effort is designated for class participation, our results show that it can affect the quality and quantity of interactions.
References:
Moore, J. L., & Marra, R. M. (2005) A comparative analysis of online discussion participation protocols.Journal of Research on Technology in Education, 38(2), 191-212.
STUDENT VERSION:
According to Moore and Marra's (2005) case study, which observed two online courses, students in the first course implemented a constructive argumentation approach while students in second course had less structure for their postings. As they stated, when instructors create online discussion board activities, they must answer at least two questions. These questions are: "What is the objective of the discussions?" And "How important are online discussions in comparison to the other activities that students will perform?". According to their findings, the discussion activities that were designed based on the answers to these questions can influence the quality and quantity of interactions (Moore & Marra, 2005).
References:
Moore, J. L., & Marra, R. M. (2005) A comparative analysis of online discussion participation protocols.Journal of Research on Technology in Education, 38(2), 191-212.
Which of the following is true for the students work;
Word-for-word plagiarism
Paraphrasing plagiarism
Not Plagiarism
ANSWER: IT IS NOT PLAGIARISM
Explanation: plagiarism is the act of extracting knowledge from someone's literature work, without acknowledging the literature work. In other words, this can be called a theft of knowledge, because when you failed to acknowledge the literature source that helped you to produce your paper work, it means you have claimed to be the original owner of that knowledge.
This is not a Plagiarism because the student has acknowledged the source of the knowledge in it's literature work. The original source and the student has cited the same literature work, this why their work looks similar but not exactly the same. So the student has not committed Plagiarism
A steel ship deck plate is 30 mm thick and 12 m wide. It is loaded with a nominal uni- axial tensile stress of 70 MPa. It is operated below its ductile-to-brittle transition temperature with KIc equal to 38.3 MPa. If a 65-mm-long central transverse crack is present, estimate the tensile stress at which catastrophic failure will occur. Compare this stress with the yield strength of 240 MPa for this steel.
Answer:
The answer is given in the attachments
Explanation:
Water is boiled in a pan covered with a poorly fitting lid at a specified location. Heat is supplied to the pan by a 2-kW resistance heater. The amount of water in the pan is observed to decrease by 1.19 kg in 30 minutes. If it is estimated that 75 percent of electricity consumed by the heater is transferred to the water as heat, determine the local atmospheric pressure in that location
Answer:
[tex]P_{atm} = 87.5\,kPa[/tex]
Explanation:
The heat required to boil the water in the pan is:
[tex]Q = \eta_{e}\cdot \dot W_{e} \cdot \Delta t[/tex]
[tex]Q = 0.75 \cdot (2\,kW)\cdot (30\, min)\cdot (\frac{60\,sec}{1\, min} )[/tex]
[tex]Q = 2700\,kJ[/tex]
Since the pan is accompained with a poorly fitting lid, the heating process is isobaric and change on specific enthalpy is obtained by following expression:
[tex]\Delta h = \frac{Q}{\Delta m}[/tex]
[tex]\Delta h = \frac{2700\,kJ}{1.19\,kg}[/tex]
[tex]\Delta h = 2268.908\,\frac{kJ}{kg}[/tex]
Then, the local atmospheric pressure can be estimated by looking for the saturation pressure related to the change on specific enthalpy at property tables for saturated water:
[tex]P_{atm} = 87.5\,kPa[/tex]
Both portions of the rod ABC are made of an aluminum for whichE = 70 GPa. Knowing that the magnitude of P is 4 kN, determine(a) the value of Q so that the deflection at A is zero, (b) the correspondingdeflection of B.0.4 m0.5 m
Explanation:
Δ[tex]L_{BC}[/tex] = Δ[tex]L_{AB}[/tex]
[tex]\frac{(Q - 4000)(0.5)}{3.14* 0.03 *0.03 *70*10^{9} }[/tex] (1)
= [tex]\frac{4000*0.4}{3.14*0.01*0.01*70*10^{9} }[/tex]
Q = 32,800 N
now put this value in equation 1.
Deflection of B = [tex]\frac{(32800-4000)(0.5)}{3.14*0.03*0.03*70*10^{9} }[/tex]
= 0.0728 mm
8.2.1: Function pass by reference: Transforming coordinates. Define a function CoordTransform() that transforms the function's first two input parameters xVal and yVal into two output parameters xValNew and yValNew. The function returns void. The transformation is new
Answer:
The output will be (3, 4) becomes (8, 10)
Explanation:
#include <stdio.h>
//If you send a pointer to a int, you are allowing the contents of that int to change.
void CoordTransform(int xVal,int yVal,int* xNew,int* yNew){
*xNew = (xVal+1)*2;
*yNew = (yVal+1)*2;
}
int main(void) {
int xValNew = 0;
int yValNew = 0;
CoordTransform(3, 4, &xValNew, &yValNew);
printf("(3, 4) becomes (%d, %d)\n", xValNew, yValNew);
return 0;
}
You are designing a spherical tank to hold water for a small village in a developing country. The volume of liquid it can hold can be computed as V = πh2[3R − h]3 where V = volume (m3), h = depth of water in tank (m), and R = the tank radius (m).
Answer:
A. [tex]9\pi h^2 - \pi h^3 -90 = 0\\\\[/tex]
B. h1 = 2.0813772719
h2 = 2.0272465228
h3 = 2.0269057423
Explanation:
V = πh^2 x [3R − h]/3
Given v=30, R=3
[tex]30 = \pi h^2 [\frac{9-h}{3} ]\\\\9\pi h^2 - \pi h^3 -90 = 0\\\\[/tex]
B. An initial guess within the interval [0; 6] is selected,
initial guess h0 = 1.5
Newton method x₂ = x₁ - f'(x₁)/f(x₁)
h₂ = h₁ - f'(x₁)/f(x₁)
[tex]h_2 = h_1 - f'(x_1)/f(x_1)\\\\h_2 = h_1 - \frac{18\pi h-3\pi h^2}{9\pi h^2 - \pi h^3 -90}[/tex]
h1 = 2.0813772719
h2 = 2.0272465228
h3 = 2.0269057423
*6–24. The beam is used to support a dead load of 400 lb>ft, a live load of 2 k>ft, and a concentrated live load of 8 k. Determine (a) the maximum positive vertical reaction at A, (b) the maximum positive shear just to the right of the support at A, and (c) the maximum negative moment at C. Assume A is a roller, C is fixed, and B is pinned.
Answer:
(a) maximum positive reaction at A = 64.0 k
(b) maximum positive shear at A = 32.0 k
(c) maximum negative moment at C = -540 k·ft
Explanation:
Given;
dead load Gk = 400 lb/ft
live load Qk = 2 k/ft
concentrated live load Pk =8 k
(a) from the influence line for vertical reaction at A, the maximum positive reaction is
[tex]A_{ymax}[/tex] = 2*(8) +(1/2(20 - 0)* (2))*(2 + 0.4) = 64 k
See attachment for the calculations of (b) & (c) including the influence line
Which of these statements is true?
1-Gutters are installed against the soffit.
2-Fascia requires openings for ventilation.
3-Drip edges prevent water from running underneath an overhang.
4-A gutter is installed flush with the fascia.
5-A vent spacer is installed underneath the rafter insulation.
Answer:
3-Drip edges prevent water from running underneath an overhang.
Explanation:
The only correct statement is in option 3. Drip edges are structures that are connected to the roof edges of buildings to ensure that the flow of water is properly controlled. They are typically used yo prevent water from getting to other parts of the building. They are made of non-corrosive and non-staining materials to make roofs of buildings beautiful.
Answer:
Drip edges prevent water from running underneath an overhang.
Explanation:
Tanya Pierce, President and owner of Florida Now Real Estate is seeking your assistance in designing a database for her business. One of her employees has experience in developing and implementing Access-based systems, but has no experience in conceptual or logical data modeling. So, at this point Tanya only wants you to develop a conceptual data model for her system. You are to use our entity-data diagramming notation - Crows foot symbols.
Tanya has some very specific needs for her system. There are several aspects of the business that need to be represented in the data model. Of central interest are properties that are listed or sold by the company. Note that a separate division of Florida Now handles raw land, so your system only has to deal with developed property. For all types of properties, Tanya wants to keep track of the owner (client), the listing and selling dates, the asking and selling prices, the address of the property, the Multiple Listing Service (MLS) number, and any general comments. In addition, the database should store the client that purchases a property. There are some specialized data that need to be stored, depending on the type of property. For single family houses she wants to store the area (for example UCF or Conway), the size of the house in square feet, the number of bedrooms and baths, the size of the garage (for example, 2 car), and the number of stories. For condominiums, the database should track the name of the complex, the unit number, the size in square feet, the number of bedrooms and baths, and the type of community (coop or condo). For commercial properties, she needs to know the zoning, size in square feet, type (industrial, retail, or office), and the general condition of the property.
Tanya also wants the database to store information about her real estate agents, such as their name, home address, home phone number, mobile phone number, email address, and their real estate license number. Also, the database should track which agent lists and sells each piece of property. Note that she has a separate system that tracks selling agents and listings from outside brokerages, so you don’t have to worry about external agents. However, sometimes a property will be listed and sold by the same Florida Now agent, but other times one Florida Now agent will list a property and another will sell it.
Of course, Tanya thinks that it would be good to have the database track information about Florida Now’s clients, such as their name, phone number, and street and email addresses. Also, she wants to be able to record comments about the client. Florida Now offers referral fees to clients who refer potential customers to the brokerage. The database should store these referral relationships between clients, including the amount and date of the referral payment. Note that only one client can be paid for a referral. In other words, it is not possible for two clients to be paid for referring the same client.
Finally, Tanya wants to be able to use the database to examine the effectiveness of various advertising outlets. For each outlet, the database should store the name of the outlet (for example, realestate.com or the Orlando Sentinel), the main contact person and their phone number. She also wants to know how much it cost to advertise each property on any outlet used, and when a property was advertised on each outlet used for that property. Keep in mind that a property may be advertised on multiple outlets, and that the cost of advertising on an outlet might vary from property to property.
Create an entity relationship diagram that captures Tanya’s database requirements. The ERD should indicate all entities, attributes, and relationships (including maximum and minimum cardinalities). Also be sure to indicate primary key attributes.
You must draw the ERD using computer software such as Visio, PowerPoint or Word. In addition, you must resolve all M:N (many- to-many) relationships and multi-valued attributes. State any assumptions you make. Remember that your assumptions must be reasonable and must not violate any stated requirements. Think through the entities, and attributes for each entity.
Answer:
the answer is attributes for each entity
Alternating current on a power line oscillates at 60 Hz. Calculate the wavelength and determine whether transmission line effects are seen on a power line that is 1000 meters long. __/2
Answer:
Wavelength = 5,000,000 m
Explanation:
Power line has extremely low frequency and produce and transmit magnetic and electric over long distance. The radiation from power line are electromagnetic radiation since it can be classified as Radiowave. Hence using the formula:
Velocity of propagation=frequency
× wavelength
We use Velocity= c = 3 × 10 ^8 m/s
f = 60Hz
wavelength = 3 ×10^8/60
Wavelength = 5,000,000 m
We can ignore the transmission line effect when the line length is less than (1/50)wavelength or (1/20)wavelength.
Seeing the transmission line length given is 1000m, we ignore the effect of transmission line as negligible
To accomplish the design project's Outback Challenge mission, your third design topic to research is a Flight Controller (i.e. manual RC transmitter) and GPS Module. The Flight Controller is not an autopilot, but rather a manual handheld flight control transmitter. If the autonomous operations fail, the Ground Base Control will take control of the UAS to manually release the rescue package (water bottle) to Outback Joe. Using the criteria found in the Outback Challenge, research and select the type of flight controller (i.e. manual handheld RC transmitter) and GPS module you feel would best accomplish the two-fold mission of searching for and delivering a rescue package to Outback Joe.
Answer:
Explanation: see attachment below
Fix the code so the program will run correctly for MAXCHEESE values of 0 to 20 (inclusive). Note that the value of MAXCHEESE is set by changing the value in the code itself. If you are not sure of how it should work then look at the Sample Runs of the next part. This part handles the beginning where it lists all the cheese types available and their prices. Note: it is a very simple fix that needs to be added to all the statements that have an array access.
Answer:
Code fixed below using Java
Explanation:
Error.java
import java.util.Random;
public class Error {
public static void main(String[] args) {
final int MAXCHEESE = 10;
String[] names = new String[MAXCHEESE];
double[] prices = new double[MAXCHEESE];
double[] amounts = new double[MAXCHEESE];
// Three Special Cheeses
names[0] = "Humboldt Fog";
prices[0] = 25.00;
names[1] = "Red Hawk";
prices[1] = 40.50;
names[2] = "Teleme";
prices[2] = 17.25;
System.out.println("We sell " + MAXCHEESE + " kind of Cheese:");
System.out.println(names[0] + ": $" + prices[0] + " per pound");
System.out.println(names[1] + ": $" + prices[1] + " per pound");
System.out.println(names[2] + ": $" + prices[2] + " per pound");
Random ranGen = new Random(100);
// error at initialising i
// i should be from 0 to MAXCHEESE value
for (int i = 0; i < MAXCHEESE; i++) {
names[i] = "Cheese Type " + (char) ('A' + i);
prices[i] = ranGen.nextInt(1000) / 100.0;
amounts[i] = 0;
System.out.println(names[i] + ": $" + prices[i] + " per pound");
}
}
}
A piston-cylinder assembly contains 0.5 lb of water. The water expands from an initial state where p1 = 40 lbf/in.2 and T1 = 300o F to a final state where p2 = 14.7 lbf/in.2 During the process, the pressure and specific volume are related by the polytropic process pv 1.2 = constant. Determine the energy transfer by work, in Btu.
To find the work done during the polytropic expansion of water in a piston-cylinder assembly, the initial and final volumes are needed to apply the polytropic process work formula. Without this information, it's not possible to calculate the energy transfer by work.
Explanation:The question asks to determine the energy transfer by work during a polytropic process where pressure p and specific volume v are related by the equation pv1.2 = constant. To find the work done by the water when it expands in a piston-cylinder assembly, you would typically use the polytropic process work formula:
W = (P1V1 - P2V2) / (n - 1)
However, to use this formula, you would need the initial and final volumes, V1 and V2, which are not provided in the question. Without these volumes or additional information such as tables or diagrams that could help find these values through the relationship of states, it is impossible to provide a numerical answer to the question asked.
) An electrical heater 100 mm long and 5 mm in diameter is inserted into a hole drilled normal to the surface of a large block of material having a thermal conductivity of 5 W/m·K. Estimate the temperature reached by the heater when dissipating 50 W with the surface of the block at a temperature of 25°C.
Answer:
Th = 40.91 C
Explanation:
We must use the equation for heat current in conduction
[tex]H = \frac{kA(Th-Tc)}{L}[/tex]
Where k is the thermal conductivity of the material
A is the cross-sectional area
(Th -Tc) is the temperature difference
and L is the length of the material
Thus
[tex]A = 2\pi r*0.1 = 0.00157079 m^{2}[/tex]
[tex]50 = \frac{5*0.00157079(Th-25)}{0.0025}[/tex]
Isolating Th, we have
[tex]Th = \frac{50*0.0025}{5*0.00157079}+25[/tex]
Th = 40.91 C
The question relates to estimating the temperature of a heater based on heat conduction, but it lacks the necessary details about the heater's material properties to provide a numerical answer.
Explanation:The student is asking about the temperature reached by an electrical heater when dissipating power. To estimate this temperature, one must consider the concept of heat conduction in which the rate of heat transfer (Q/t) is influenced by the thermal conductivity (k) of the material, surface area (A), thickness (d), and temperature difference across the material. In this problem, the heater dissipates 50 W of power, the length of the heater is 100 mm, the diameter is 5 mm, and the thermal conductivity of the surrounding material is 5 W/m·K. To calculate the temperature reached by the heater, we would typically use the equation for steady-state heat transfer. However, the question lacks sufficient details such as the properties of the heater material, which would be necessary to determine the temperature distribution and to estimate the temperature reached by the heater. Therefore, with the information provided, we can only discuss the factors involved in calculating the temperature reached by the heater but cannot provide a numerical answer.