Answer:
#Python
import re
password = input("Enter password: ")
p = re.compile('^[ABCDabcd]+.*[^e-zE-Z5-9_]{2,}[1-4][1-4]+$')
match = p.search(password)
if match == None:
print('L(r) != L -> Incorrect password')
else:
print('L(r) = L -> Correct password')
Explanation:
The regular expression needed is:
^[ABCDabcd]+.*[^e-zE-Z5-9_]{2,}[1-4][1-4]+$
To understand why see the step by step of the regex:
^[ABCDabcd]: Here we use ^ to indicate the first character of the class, then we use [] to specify a character class, then we punt ABCDabcd to indicate that the first character has to begin with a letter from a to d and finally we use a + to continue our expression.*[^e-zE-Z5-9_]{2,}: Here we use .* to specify the sequence of characters that comes after the first letter, then we put ^e-zE-Z5-9_ inside brackets, the first character, ^, tell us that the characters coming are forbidden, so the user can not use a number, letter or special character outside of the sequence defined, and finally, we have curly brackets to indicate the length of the expression, where '2,' represents that the length in the middle is at least two characters long[1-4][1-4]+$: With the two brackets in this expression the string must ends with two digits from one to fourth and the $ refers to the end of the expressionNote: if you don't have python you can use an online regex checker like myregextester, note that the string must be at least five characters long because you need one letter at the beginning, at least two characters in the middle and two numbers at the end.
Provide an argument justifying the following claim: The average (as defined here) of two Java ints i and j is representable as an int, regardless of the lower and upper bounds on the value of an int.
Answer:
public static int average(int j, int k) {
return (int)(( (long)(i) + (long)(j) ) /2 );
}
Explanation:
The above code returns the average of two integer variables
Line 1 of the code declares a method along with 2 variables
Method declared: average of integer data type
Variables: j and k of type integer, respectively
Line 2 calculates the average of the two variables and returns the value of the average.
The first of two integers to average is j
The second of two integers to average is k
The last parameter ensures average using (j+k)/2
A floor in an office building is made of a reinforced concrete slab 10 in. deep and spans 20 ft. For the purposes of calculating the tributary load you can assume the slab is 10 ft. wide. This scenario can be modelled as a simply supported beam, 20 ft. long, 10 in. deep and 10 ft. wide.
Calculate the maximum factored maximum moments and shears on this structure using the appropriate load combinations discussed in class.
Note which loading combination is critical.
You can assume the uniform live load is 50 psf.
Hint: since this is not a member that carries lateral load, there are no significant wind or earthquake loads contributing to the shear and moments in the member.
Since this is not on the roof there are no roof or snow loads. h = 10 in. 20 ft.
Hi, your question didn't have any images, hence I am attaching the complete question in the attachment below.
Answer:
Please refer to the attachment below for answers.Explanation:
Please refer to the attachment for explanation.A 220-V electric heater has two heating coils that can be switched such that either coil can be used independently or the two can be connected in series or parallel, for a total of four possible configurations. If the warmest setting corresponds to 2,000-W power dissipation and the coolest corresponds to 300 W, find the resistance of each coil.
Answer:
The resistances of both coils are 131.7 Ω and 29.64 Ω.
Explanation:
Since, there are two coils, they can be used independently or in series or parallel. The power is given as:
Power = P = VI
but, from Ohm's Law:
V = IR
I = V/R
therefore,
P = V²/R
R = V²/P
Hence, the resistance (R) and (P) are inversely proportional. Therefore, the maximum value of resistance will give minimum power, that is, 300 W. And the maximum resistance will be in series arrangement, as in series the total resistance gets higher than, any individual resistance.
Therefore,
Rmax = V²/Pmin = R1 + R2
R1 + R2 = (220 V)²/300 W
R1 + R2 = 161.333 Ω ______ en (1)
Similarly, the minimum resistance will give maximum power. And the minimum resistance will occur in parallel combination. Because equivalent resistance of parallel combination is less than any individual resistance.
Therefore,
(R1 R2)/(R1 + R2) = (220 V)²/2000 W
using eqn (1), we get:
(R1 R2) / 161.333 Ω = 24.2 Ω
R1 R2 = 3904.266 Ω²
R1 = 3904.266 Ω²/R2 _____ eqn (2)
Using this value of R1 in eqn (1), we get:
3904.266/R2 +R2 = 161.333
(R2)² - 161.333 R2 +3904.266 = 0
Solving this quadratic eqn we get two values of R2 as:
R2 = 131.7 Ω OR R2 = 29.64 Ω
when ,we substitute these values in eqn (1) to find R1, we get get the same two values as R2, alternatively. This means that the two coils have these resistance, and the order does not matter.
Therefore, the resistance of both coils are found to be 131.7 Ω and 29.64 Ω
Given A = {1,2,42,57,99,538,677}, B = {1,5,6,7,{2,3} , and C ={1,{7}, {8,9}}, answer the following questions, use the proper notation:Write an inequality that represents the cardinality of any proper subset of A. Let’s say the cardinality of the subset is C.
Answer:
c < 7
Explanation:
The cardinal indicates the number or quantity of the elements of a set, be this finite or infinite quantity.
Given, A = {1, 2, 42, 57, 99, 538, 677}
B = {1, 5, 6, 7, {2, 3} }
C = {1, {7}, {8, 9} }
Let's say the cardinality of the subset is: c
Inequality that represents the cardinality of any proper subset of A is: c < 7
Hope this helps!
An inequality that represents the cardinality of any proper subset of A is c<7.
Given, A = {1, 2, 42, 57, 99, 538, 677}
B = {1, 5, 6, 7, {2, 3} }
C = {1, {7}, {8, 9} }
Inequalities are the mathematical expressions in which both sides are not equal. In inequality, unlike in equations, we compare two values. The equal sign in between is replaced by less than (or less than or equal to), greater than (or greater than or equal to), or not equal to sign.
Let's say the cardinality of the subset is: c
Inequality that represents the cardinality of any proper subset of A is: c < 7
Therefore, an inequality that represents the cardinality of any proper subset of A is c<7.
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Given an array of primitive integers named grades, fill in the blank to complete the following code that calculates the average of all the grades: double average = 0; average + grades[ average (= grades.length; Use proper spacing per the course style guide. Do not include additional spaces at the beginning or end.
Answer:
C++ snippet is given below with appropriate comments and explanation
Explanation:
Code snippet:
double average=0;//declaring variable
//using for loop
for(int i=0;i<grades.length;i++)
{
average+=grades[i];//add each grade to average
}
average/=grades.length;//find average
Explanation :
Above code snippet need a for loop to add each grade from the array to the variable average,
average/=grades.length; this will compute average.
An inductor (L = 400 mH), a capacitor (C = 4.43 µF), and a resistor (R = 500 Ω) are connected in series. A 44.0-Hz AC generator connected in series to these elements produces a maximum current of 385 mA in the circuit.
(a) Calculate the required maximum voltage ΔVmax.
(b) Determine the phase angle by which the current leads or lags the applied voltage.
Answer:
(A) Maximum voltage will be equal to 333.194 volt
(B) Current will be leading by an angle 54.70
Explanation:
We have given maximum current in the circuit [tex]i_m=385mA=385\times 10^{-3}A=0.385A[/tex]
Inductance of the inductor [tex]L=400mH=400\times 10^{-3}h=0.4H[/tex]
Capacitance [tex]C=4.43\mu F=4.43\times 10^{-3}F[/tex]
Frequency is given f = 44 Hz
Resistance R = 500 ohm
Inductive reactance will be [tex]x_l=\omega L=2\times 3.14\times 44\times 0.4=110.528ohm[/tex]
Capacitive reactance will be equal to [tex]X_C=\frac{1}{\omega C}=\frac{1}{2\times 3.14\times 44\times 4.43\times 10^{-6}}=816.82ohm[/tex]
Impedance of the circuit will be [tex]Z=\sqrt{R^2+(X_C-X_L)^2}=\sqrt{500^2+(816.92-110.52)^2}=865.44ohm[/tex]
So maximum voltage will be [tex]\Delta V_{max}=0.385\times 865.44=333.194volt[/tex]
(B) Phase difference will be given as [tex]\Phi =tan^{-1}\frac{X_C-X_L}{R}=\frac{816.92-110.52}{500}=54.70[/tex]
So current will be leading by an angle 54.70
a(n)___ branch circuit supplies two or more receptacles or outlets for lighting and appliances
Answer: General purpose branch circuit
Explanation:
General purpose branch circuit are the type of circuits that are used mainly to supply light to two or more receptacle outlets for small appliances. This circuits are about 120v can be used either in residential, commercial and industrial buildings.
A soil specimen was tested to have a moisture content of 32%, a void ratio of 0.95, and a specific gravity of soil solids of 2.75. Determine:
a. the degree of satruation
b. porosity
c. dry unit weight
Answer:
a. 0.9263
b. 0.4872
c. 13.83kN/m[tex]^{3}[/tex]
Explanation:
moisture content (ω) = 0.32
void ratio (e) = 0.95
specific gravity ([tex]G_{s}[/tex]) = 2.75
the degree of satruation (S) = [tex]\frac{w . G_{s} }{e}[/tex] =0.32×2.75/0.95 = 0.9263
b. porosity (n) = [tex]\frac{e}{e + 1}[/tex] = 0.95/(0.95 + 1)= 0.4872
c. dry unit weight (γ[tex]_{d}[/tex]) = [tex]\frac{G_{s} . V_{w} }{1 + e}[/tex]
taking specific unit weight of water (V[tex]_{w}[/tex])= 9.81kN/m[tex]^{3}[/tex]
γ[tex]_{d}[/tex] = 2.75 × 1000/(1 + 0.95) = 13.83kN/m[tex]^{3}[/tex]
Ultra-thin semiconductor materials are of interest for future nanometer-scale transistors, but can present undesirably high resistance to current flow. How low must the resistivity of a semiconductor material be, to ensure that the resistance of a 2nm-thick, 10nm-long, 100nm-wide region does not exceed 100 ohms?
Answer:
p = 2*10^(-7) ohm m
Explanation:
The resistivity and Resistance relationship is:
[tex]p = \frac{R*A}{L}[/tex]
For lowest resistivity with R < 100 ohms.
We need to consider the possibility of current flowing across minimum Area and maximum Length.
So,
Amin = 2nm x 10 nm = 2 * 10^(-16) m^2
Lmax = 100nm
Using above relationship compute resistivity p:
[tex]p = \frac{100*2*10^(-16)}{100*10^(-9)} \\\\p = 2 * 10^(-7)[/tex]
Answer: p = 2*10^(-7) ohm m
Two substances, A and B, initially at different temperatures, come into contact and reach thermal equilibrium. The mass of substance A is 6.01 g and its initial temperature is 20.0 degrees Celsius. The mass of substance B is 25.6 g and its initial temperature is 52.2 degrees Celsius. The final temperature of both substances at thermal equilibrium is 46.1 degrees Celsius. If the specific heat capacity of substance B is 1.17 J/g degrees Celsius, what is the specific heat capacity of substance A
Answer:
The specific heat capacity of substance A is 1.16 J/g
Explanation:
The substances A and B come to a thermal equilibrium, therefore, the heat given by the hotter substance B is absorbed by the colder substance A.
The equation becomes:
Heat release by Substance B = Heat Gained by Substance A
The heat can be calculated by the formula:
Heat = mCΔT
where,
m = mass of substance
C = specific heat capacity of substance
ΔT = difference in temperature of substance
Therefore, the equation becomes:
(mCΔT) of A = (mCΔT) of B
FOR SUBSTANCE A:
m = 6.01 g
ΔT = Final Temperature - Initial Temperature
ΔT = 46.1°C - 20°C = 26.1°C
C = ?
FOR SUBSTANCE B:
m = 25.6 g
ΔT = Initial Temperature - Final Temperature
ΔT = 52.2°C - 46.1°C = 6.1°C
C = 1.17 J/g
Therefore, eqn becomes:
(6.01 g)(C)(26.1°C) = (25.6 g)(1.17 J/g)(6.1°C)
C = (182.7072 J °C)/(156.861 g °C)
C = 1.16 J/g
Universal Containers (UC) has a requirement to expose a web service to their business partners. The web service will be used to allow each business partner to query UC's Salesforce instance to retrieve the status of orders. The business partner should only be allowed access to orders for which the business partner is the fulfillment vendor. The Architect does not want the business partners to utilize the standard APIs and would prefer a custom API be developed. Which three design elements should the Architect consider in order to ensure the data security of the solution?
Answer:
"- Set the Orders object's sharing settings to Private in the Org-Wide Defaults
_Provide each partner with their own Salesforce login set to API Enabled on the profile
-Develop a custom Apex web service using the "With Sharing" keyword"
Explanation:
Universal Containers (UC) has a requirement to expose a web service to their business partners. The web service will be used to allow each business partner to query UC's Salesforce instance to retrieve the status of orders. The business partner should only be allowed access to orders for which the business partner is the fulfillment vendor. The Architect does not want the business partners to utilize the standard APIs and would prefer a custom API be developed. Which three design elements should the Architect consider in order to ensure the data security of the solution?
A. Query the Orders object with Dynamic SOQL based upon the fulfillment ID.
B. Set the Orders object's sharing settings to Private in the Org-Wide Defaults
C. Provide each partner with their own Salesforce login set to API Enabled on the profile.
D. Develop a custom Apex web service with a fulfillment ID input attribute
E. Develop a custom Apex web service using the "With Sharing" keyword.
The above should be a follow up option to the question
The Architect should consider the following design
"- Set the Orders object's sharing settings to Private in the Org-Wide Defaults
_Provide each partner with their own Salesforce login set to API Enabled on the profile
-Develop a custom Apex web service using the "With Sharing" keyword"
There is need for some sharing rule between the architect and the user
Write a simple calculator program. Your program should ask for three things two whole numbers and an operator in the form of an expression like: 3 * 2 Use a select case structure to determine what operation needs to be performed on the two numbers. Your program should handle the arithmetic functions Add, Subtract, Multiply, and Divide (Depending on the operator entered).
Answer:
The solution code is written in Java.
Scanner input = new Scanner(System.in); System.out.print("Enter operator: "); String operator = input.nextLine(); System.out.print("Enter first integer: "); int num1 = input.nextInt(); System.out.print("Enter second integer: "); int num2 = input.nextInt(); int result = 0; switch(operator){ case "+": result = num1 + num2; break; case "-": result = num1 - num2; break; case "*": result = num1 * num2; break; case "/": result = num1 / num2; break; default: System.out.println("Invalid operator"); } System.out.println(result);Explanation:
To ask for the user input for two whole numbers and an operator, we can use Java Scanner class object. Since the input operator is a string, we can use nextLine() method to get the operator string (Line 3). We use nextInt() method to get whole number input (Line 5 & 7).
Next we use the switch keyword and pass the operator into the switch structure to determine which case statement should be executed. For example, if the input operator is "*" the statement "result = num1 * num2; " will run and multiply num1 with num2.
Write a program to store numbers from 1 to 100 in an array. Print out all the even numbers from the array. Use the enhanced FOR loop for printing out the numbers.
Answer:
The java program to print all even numbers from 1 to 100 is given below.
import java.util.*;
public class Program
{
// integer array of size 100
static int[] num = new int[100];
public static void main(String[] args) {
// array initialized using for loop with values from 1 to 100
for(int j=0; j<100; j++)
{
num[j] = j+1;
}
System.out.println("Even numbers from 1 to 100 are ");
// enhanced for loop
for(int n : num)
{
// testing each element of the array
// only even numbers will be displayed
if( (n%2) == 0)
System.out.print(n + " ");
}
}
}
OUTPUT
Even numbers from 1 to 100 are
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100
Explanation:
The program works as described.
1. An integer array, num, of size 100 is declared.
2. Inside for loop which executes 100 times, array is initialized with numbers from 1 to 100.
3. An enchanced for loop differs from normal for loop such that it doesn't has initialization and increment or decrement conditions.
4. The syntax for an enchanced for loop is shown below.
for( datatype variable_name : array_name )
{ }
In the above syntax, the datatype of the variable_name should be the same as that of the array_name.
The array used in program is shown below.
for(int n : num)
5. Inside enhanced for loop, if statement is included to test each element of array, num, for even or odd number.
if( (n%2) == 0)
6. If the number is even, it is displayed followed by a space.
System.out.print(n + " ");
7. The method println() differs from print() such that new line is inserted after the message is displayed.
8. This program can also be used to display odd numbers by changing the condition inside if statement.
What is the minimum hose diameter of an ideal vacuum cleaner that could lift a 14 kg dog off the floor?
To determine the minimum hose diameter for lifting a 14 kg dog with a vacuum cleaner, physics principles related to pressure and force are applied. The calculation involves the dog's weight and the pressure difference a vacuum needs to create over the hose's cross-sectional area. However, without specific vacuum specifications, an exact diameter cannot be determined.
Explanation:Calculating the Minimum Hose Diameter for a Vacuum Cleaner to Lift a Dog
To determine the minimum hose diameter of an ideal vacuum cleaner that could lift a 14 kg dog off the floor, we need to understand the principles of pressure and force in a vacuum system. This involves a bit of physics, specifically relating to the pressure difference created by the vacuum and the surface area over which this pressure acts.
The force required to lift the dog can be calculated using the formula F = m × g, where m is the mass of the dog (14 kg) and g is the acceleration due to gravity (approximately 9.8 m/s2). This gives us a force of approximately 137.2 N (newtons).
To lift the dog, the vacuum cleaner must create a pressure difference greater than the weight of the dog distributed over the area of the hose's opening. The pressure (Π) required can be found using Π = F/A, where A is the cross-sectional area of the hose. To find the minimum diameter, we rearrange the area formula A = πr2 (where r is the radius of the hose) to solve for diameter, taking into account that the area must be sufficient to create a pressure difference capable of lifting the dog.
Without specific pressure values from a vacuum cleaner, we cannot calculate an exact diameter but can assert the importance of a vacuum cleaner's pressure capability and the diameter's role in generating enough lift. In an ideal scenario, the vacuum would have to reduce the air pressure significantly inside the hose compared to the atmospheric pressure outside to create enough lift force.
Therefore, while this offers a theoretical framework, the practical application would depend on specific vacuum cleaner specifications, including its ability to create a low enough pressure and maintain a high flow rate, which were not provided in this question.
Explain the conductivity results observed for ionic compounds in the solid state and in aqueous solution.i.Solid ionic compounds don’t have a conductivity because there isn’t any free space. However, in an aqueous solution ionic compounds have free space causing it to be conductive
Answer:
Aqueous solution of ionic compounds conduct electricity while solid ionic compounds don't.
Explanation:
Ionic compound conduct electricity when liquid or in aqueous solution that is resolved in water because the ionic bonds of the compound become weak and the ions are free to move from place to place.
Ionic compounds don't conduct electricity while in solid state because the ionic bonds are to strong and ions cannot move around with lack of space for movement which makes the electric conductivity zero.
Solid ionic compounds don't have any electrical conductivity as they are not free to move. Hence they lack the free space as compared to the molten or aqueous solution where there exist some gaps and pockets.
Since the melting of the ions takes up lots of heat they are in a molten state and such ions can conduct electricity when they are dissolved in water. Hence they can move around freely.The solids ions that dissolve in the water are called electrolytes as compounds such as acids.
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A particle is moving along a straight line with an initial velocity of 3 m/s when it is subjected to a deceleration of a = - 1.1 v^1/2 m/s^2 .A. Determine how far it travels before it stops.B. How much time does it take?
Answer:
Explanation:
Given that
initial velocity ,[tex]v= 3 m/s[/tex]
[tex]a=-1.1v^{\dfrac{1}{2}}[/tex]
We know that
[tex]a=v\dfrac{dv}{dx}[/tex]
Lets take x is the distance before coming to the rest.
The final speed of the particle = 0 m/s
[tex]v\dfrac{dv}{dx}=-1.1v^{\dfrac{1}{2}}[/tex]
[tex]\dfrac{dv}{dx}=-1.1v^{-\dfrac{1}{2}}[/tex]
[tex]v^{\dfrac{1}{2}}{dv}=-1.1dx[/tex]
[tex]\int_{3}^{0}v^{\dfrac{1}{2}}{dv}=-\int_{0}^{x}1.1dx[/tex]
[tex]\left [v^{\dfrac{3}{2}}\times \dfrac{2}{3}\right]_3^0=-1.1x[/tex]
[tex]3^{\dfrac{3}{2}}\times \dfrac{2}{3}=1.1x[/tex]
[tex]x=\dfrac{3.46}{1.1}\ m\\x=3.14\ m[/tex]
(b)time taken by it
[tex]a=\frac{\mathrm{d} v}{\mathrm{d} t}=-1.1\sqrt{v}[/tex]
[tex]\int_{3}^{0}\frac{dv}{\sqrt{v}}=-1.1\int_{0}^{t}dt[/tex]
[tex]\int_{0}^{3}\frac{dv}{\sqrt{v}}=1.1\int_{0}^{t}dt[/tex]
[tex]2\times 3\sqrt{3}=1.1t[/tex]
[tex]t=9.44\ s[/tex]
Which scenarios are examples of negative stabilizing feedbacks?
Answer:
Examples includes
Biological Examples
1. Body temperature humans -in humans the hypothalamus intercept and counters fluctuations in the body temperature
2. Blood pressure in humans; when signals of increased blood pressure are sent to the brain from the blood vessels, it responds by sending signals to the heart to slow down the rate of heart beat
Mechanical Example
1. The toilet ballcock rises in as the water level in it rises, and closing the inlet valve to turns off the water when the allowable water level is reached.
Explanation:
Negative Stabilizing Feedback
A reaction that causes a decrease in function is a negative stabilizing feedback . It is initiated as a response to a type of stimulus. It normally leads to a reduction in the system output as such, the feedback stabilises system. in biological terms, this is known as homeostatis, while in mechanics it is called equilibrium. an appraisal of person's work is also a type of negative feedback.
The Program Manager (PM) should request a Counterintelligence (CI) analysis when an acquisition program containing Critical Program Information (CPI) is initiated. The CI analysis focuses on _____________________ and on how to counter the opposition's collection efforts.
Based on the provided information, The CI analysis focuses on how the opposition sees the program and on how to counter the opposition's collection efforts.
According to the given question, we are to discuss about Program Manager and how he should request a Counterintelligence analysis in case of acquisition program containing Critical Program Information.
As a result if this we can see that how the opposition sees the program should be the first thing that should be considered by Program Manager.
Therefore, The CI analysis focuses on how the opposition sees the program and on how to counter the opposition's collection efforts.
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A Counterintelligence (CI) analysis, requested by a Program Manager (PM) for acquisition programs with Critical Program Information (CPI), primarily focuses on identifying potential threats like foreign intelligence entities, understanding how these entities may seek to compromise the CPI, and devising strategies to counter such threats.
Explanation:A Program Manager (PM) should indeed request a Counterintelligence (CI) analysis when initiating an acquisition program involving Critical Program Information (CPI). The primary focus of a CI analysis is threat identification and mitigation. It is centered on identifying potential threats such as foreign intelligence entities and determining how these entities might access or compromise the CPI.
Additionally, the CI analysis also develops strategies on how to effectively counter the adversary's collection attempts to ensure the safeguarding of sensitive information.
For example, if the program involves the development of a military technology, the CI team would determine the potential adversaries who might be interested in the technology, their possible collection methods, and ways to counter such collection efforts. This could entail securing communication lines, implementing stricter access control, or even disseminating misinformation to confuse potential spies.
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For the following pairs of sinusoidal time functions, determine which one leads/lags and by how much. (a) ????1(????)=4sin(6π×104????+60°) V and ????2(????)=2cos(6π×104????−20°) V. (b) ????(????)=10cos(400????−75°) V and ????(????)=4sin(400????+30°) A.
Answer:
The question is incomplete, the complete question is given below
"For the following pairs of sinusoidal time functions, determine which one leads/lags and by how much. (a) V1(t) =4sin(6π×10^4t+60°)V and V(t)2=2cos(6π×10^4t−20°)V. (b) V(t)=10cos(400t−75°) V and I(t)=4sin(400t+30°) A.
Answer
A. V2(t) leads V1(t) by 10°
B. I(t) leads V(t) by 15°
Explanation:
First we express the relationship between sine and cosine of a value.
The expression is giving below Cos (wt) =Sin(wt+90)
Hence for the equations above, we write
a. We can v(t) as
V1(t)=4Sin(6π*10^4+90°-30°)
V1(t)=4Cos(6π*10^4-30°)
Comparing to
V2(t)=4Cos(6π*10^4-20°)
Comparing the angle, we notice that V2(t) leads V1(t) by 10°
b. We can write the current wave form as
I(t)=4sin(400t+90°-60°)
I(t)=4Cos(400t-60°)
If we compare with V(t)=10cos(400t−75°)
I.e 4Cos(400t-60°)=10cos(400t−75°)
We can conclude that I(t) leads V(t) by 15°
Determine the sinusoidal time functions corresponding to each of the following phasors: (a) 5∠25° V, ????=1000 rad/s (????) −????5 A, ????=100 Hz
Answer:
The question is incomplete.the complete question is giving below
"Determine the sinusoidal time functions corresponding to each of the following phasors: (a) 5<25°V, w = 1000 rad/s (b) - j5 A, f = 100 Hz
answer
a. V(t)=5√(2)sin(1000t+25⁰)v
b. -5√(2)cos200πt A
Explanation:
note that the sinusoidal time function is express as
y(t)=yₙsin(wt+α)
where w is the angular frequency in rad/s, and α is the angle .
a. to represent 5<25°V, w = 1000 rad/s. first we express it in polar form i.e
V(t)=5eⁱ²⁵
in sinusoidal time function we have
V(t)=Vₙsin(wt+α)
Vₙ=5√(2)v, the √(2) convert the amplitude into effective or RMS value
w=1000rad/secs
α=25⁰
Hence if we substitute,we arrive at
V(t)=5sin(1000t+25⁰)v
b. for - j5 A, f = 100 Hz
in polar form we have
i(t)=5eⁱ⁹⁰
and w=2πf=2*π*100=200π
hence we have
i(t)=5√(2)sin(200πt+90)= (-5sin200πt)A
A polymeric extruder is turned on and immediately begins producing a product at a rate of 10 kg/min. An operator realizes 20 minutes later that the production rate is too low, and increases the production rate to an immediate 15 kg/min. An hour later, an emergency causes the outlet valve to rapidly adjust to 1 kg/min. One minute later, the emergency is resolved, and the outlet valve is allowed to rapidly readjust to 10 kg/min. Plot production rate m(t) in kg/min against time t in min. Determine the production rate function m(t) in the time domain, and then determine the Laplace transform of m(t).
Answer:
The plot of the function production rate m(t) (in kg/min) against time t (in min) is attached to this answer.
The production rate function M(t) is:
[tex]m(t)=[H(t)\cdot10+H(t-20)\cdot5-H(t-80)\cdot14+H(t-81)\cdot9]kg/min[/tex] (1)
The Laplace transform of this function is:
[tex]\displaystyle m(s)=[\frac{10+5e^{-20s}-14e^{-80s}+9e^{-81s}}{s}]kg/min[/tex] (2)
Explanation:
The function of the production rate can be considered as constant functions by parts in the domain of time. To make it a continuous function, we can use the function Heaviside (as seen in equation (1)). To join all the constant functions, we consider at which time the step for each one of them appears and sum each function multiply by the function Heaviside.
For the Laplace transform we use the following rules:
[tex]\mathcal{L}[f(x)+g(x)]=\mathcal{L}[f(x)]+\mathcal{L}[g(x)]=F(s)+G(s)[/tex] (3)
[tex]\mathcal{L}[aH(x-b)]=\displaystyle\frac{ae^{-bs}}{s}[/tex] (4)
Air flows through a device in which heat and work is exchanged. There is a single inlet and outlet, and the flow at each boundary is steady and uniform. The inlet flow has the following properties: flowrate 50 kg/s, T 25 °C, and velocity 150 m/s. Heat is added to the device at the rate of 42 MW, and the shaft work is -100 kW (assume the efficiency is 100 %). The exit velocity is 400 m/s Calculate the specific stagnation enthalpy (J/kg or kJ/kg) at the inlet, and use the 1st Law to calculate the specific stagnation enthalpy at the exit. Assume constant cp1.0 kJ/kg -K. Calculate the temperature of the air at the exit. Was the assumption of constant cp a good one?
Answer:
11548KJ/kg
10641KJ/kg
Explanation:
Stagnation enthalpy:
[tex]h_{T} = c_{p}*T + \frac{V^2}{2}[/tex]
given:
cp = 1.0 KJ/kg-K
T1 = 25 C +273 = 298 K
V1 = 150 m/s
[tex]h_{1} = (1.0 KJ/kg-K) * (298K) + \frac{150^2}{2} \\\\h_{1} = 11548 KJ / kg[/tex]
Answer: 11548 KJ/kg
Using Heat balance for steady-state system:
[tex]Flow(m) *(h_{1} - h_{2} + \frac{V^2_{1} - V^2_{2} }{2} ) = Q_{in} + W_{out}\\[/tex]
Qin = 42 MW
W = -100 KW
V2 = 400 m/s
Using the above equation
[tex]50 *( 11548- h_{2} + \frac{150^2 - 400^2 }{2} ) = 42,000 - 100\\\\h_{2} = 10641KJ/kg[/tex]
Answer: 10641 KJ/kg
c) We use cp because the work is done per constant pressure on the system.
Is it possible to maintain a pressure of 10 kpa in a condenser that is being cooled by river water entering at 20 C?
Answer:
Yes,it possible to maintain a pressure of 10 kpa in a condenser that is being cooled by river water entering at 20 C.
Explanation:
Yes,it possible to maintain a pressure of 10 kpa in a condenser that is being cooled by river water entering at 20 C.
Reason:
If we look in the steam tables at pressure of 10 KPa,we will find that at this pressure saturation temperature of steam is 45.81 degree Celsius which is higher than 20 degree Celsius river water uses to cool the condenser.
Maintaining a pressure of 10 kPa in a condenser cooled by river water entering at 20°C is feasible with careful management of cooling water flow rate, temperature, and condenser design.
It is possible to maintain a pressure of 10 kPa in a condenser that is cooled by river water entering at 20°C, but there are a few things to take into account.
The condenser's design, temperature, and flow rate of the cooling medium—in this example, river water—all have an impact on the pressure inside the unit.
You must make sure that the cooling water's temperature and flow rate are sufficient to disperse the heat produced in the condenser in order to maintain a pressure of 10 kPa in the unit. This could entail regulating the temperature of the water entering the condenser or the cooling water's flow rate.
Furthermore, the condenser's efficiency and design are important considerations. To maintain the required pressure, a well-designed and efficient condenser will need less cooling water and work.
Overall, a condenser cooled by river water at 20°C can sustain a pressure of 10 kPa, but doing so necessitates carefully weighing variables including temperature, condenser design, and cooling water flow rate.
Air at 40°C flows over a long, 25-mm-diameter cylinder with an embedded electrical heater. In a series of tests, measurements were made of the power per unit length, P’, required to maintain the cylinder surface temperature at 300°C for different free stream velocities u of the air. The results are as follows:
Air velocity, u (m/s) 1 2 4 8 12
Power, P’ (W/m) 450 658 983 1507 1963
(a) Determine the convection coefficient for each velocity, and display your results graphically.
(b) Assuming the dependence of the convection coefficient on the velocity to be of the form h = Cu n , determine the parameters C and n from the results of part (a)
Answer:
a) See attachment
b) C = 21.626 W / m^2 .K , n = 0.593
Explanation:
a)
dT = 300 - 40 = 160 K
A = pi*D*l where D = 0.025 m
Power = P' * l = h * dT * A
P' l = h * pi * D * l* dT
Hence,
h = P' / (pi*D*dT)
We will use the above equation to compute for respective values of P'
Note: The results are tabulated and attached
b)
Assuming the dependence of the convection coefficient on the velocity to be of the form h=CV^n, determine the parameters C and n from the results of part (a).
Taking logarithm on both sides:
Ln (h) = Ln(C) + n*Ln(V)
n = (Ln(h2) - Ln(h1)) / (Ln(V2) - Ln(V1))
n = (Ln (32.223/22.037)) / Ln(2))
n = 0.593
Using regression we can compare:
C = 21.626 W/m^2 . K
A 0.9% solution of NaCl is considered isotonic to mammalian cells. what molar concentration is this?
Answer:
58.44 g/mol The Molarity of this concentration is 0.154 molar
Explanation:
the molar mass of NaCl is 58.44 g/mol,
0.9 % is the same thing as 0.9g of NaCl , so this means that 100 ml's of physiological saline contains 0.9 g of NaCl. One liter of physiological saline must contain 9 g of NaCl. We can determine the molarity of a physiological saline solution by dividing 9 g by 58 g... since we have 9 g of NaCl in a liter of physiological saline, but we have 58 grams of NaCl in a mole of NaCl. When we divide 9 g by 58 g, we find that physiological saline contains 0.154 moles of NaCl per liter. That means that physiological saline (0.9% NaCl) has a molarity of 0.154 molar. We can either express this as 0.154 M or 154 millimolar (154 mM).
A rectangular weir is in a rectangular channel 2.9 m wide. The length of the weir is 1.9 m and is centered in the channel. If the water level is 0.2 m above the surface of the weir, what is the discharge in the channel (m3/sec)
Answer:
discharge = 0.310976 m³/s
Explanation:
given data
rectangular channel wide = 2.9 m
length of weir L = 1.9 m
water level H = 0.2 m
solution
we get here discharge that is express as
discharge = [tex]\frac{2}{3} * C_d * L* \sqrt{2g} * H^{\frac{3}{2} }[/tex] ............................1
we consider here Coefficient of discharge Cd = 0.62
put here value we get
discharge = [tex]\frac{2}{3} * 0.62 * 1.9* \sqrt{2*9.8} * 0.2^{\frac{3}{2} }[/tex]
discharge = 0.310976 m³/s
Suppose that the voltage is reduced by 10 percent (to 90 VV). By what percentage is the power reduced? Assume that the resistance remains constant.
Answer:
The power is reduced by 19 percent.
Explanation:
The formula of power is given by:
[tex]P = \frac{V^{2}}{R}[/tex]
In which V is the voltage, and R is the resistance.
I am going to use R = 1 in both cases.
With the original voltage, V = 1, we have
[tex]P = \frac{V^{2}}{R} = \frac{1}{1} = 1[/tex]
With the modified voltage, V = 0.9, we have:
[tex]P = \frac{V^{2}}{R} = \frac{0.9^{2}}{1} = 0.81[/tex]
So the power is reduced by 1-0.81 = 0.19 = 19 percent.
Create a program that keeps track of student information at a college. The student information should include name, identification number, and grade point average, with the unique identifier (key) for each student being the identification number. The implementation should be a binary search tree.
I'm finding it difficult to submit my answer.
Check the attachments below for answer and explanation
The thermal conductivity of a solid depends upon the solid’s temperature as k = a T+b where a and b are constants. The temperature in a planar layer of this solid as it conducts heat is given by:a. aT+b= x +C2b. aT+ b = C1x^2 +C2c. aT^2+ bT= C1x+ C2d. aT^2+ +bT= C1x^2+ C2e. None of these
Answer:
Answer is Option (e) - None of these
Explanation:
The step by step derivation from the fourier's law of heat conduction is as shown in the attachment below.
Where K = thermal conductivity
Consider the circuit below where R1 = R4 = 5 Ohms, R2 = R3 = 10 Ohms, Vs1 = 9V, and Vs2 = 6V. Use superposition to solve for the value of V2 in volts due to Vs1 alone. Put your answer in the box below without the units. Consider the same circuit. Now, solve for V2 in volts due to the contribution of Vs2 alone. Put your answer in the box below without the units. Consider the same circuit. Now, solve for V2 in volts due to the both Vs1 and Vs2. Put your answer in the box below without the units.Figure:Resistors are connected in series and parllel
Answer:
The value of v2 in each case is:
A) V2=3v for only Vs1
B) V2=2v for only Vs2
C) V2=5v for both Vs1 and Vs2
Explanation:
In the attached graphic we draw the currents in the circuit. If we consider only one of the batteries, we can consider the other shorted.
Also, what the problem asks is the value V2 in each case, where:
[tex]V_2=I_2R_2=V_{ab}[/tex]
If we use superposition, we passivate a battery and consider the circuit affected only by the other battery.
In the first case we can use an equivalent resistance between R2 and R3:
[tex]V_{ab}'=I_1'R_{2||3}=I_1'\cdot(\frac{1}{R_2}+\frac{1}{R_3})^{-1}[/tex]
And
[tex]V_{S1}-I_1'R_1-I_1'R_4-I_1'R_{2||3}=0 \rightarrow I_1'=0.6A[/tex]
[tex]V_{ab}'=I_1'R_{2||3}=3V=V_{2}'[/tex]
In the second case we can use an equivalent resistance between R2 and (R1+R4):
[tex]V_{ab}''=I_3'R_{2||1-4}=I_3'\cdot(\frac{1}{R_2}+\frac{1}{R_1+R_4})^{-1}[/tex]
And
[tex]V_{S2}-I_3'R_3-I_3'R_{2||1-4}=0 \rightarrow I_3'=0.4A[/tex]
[tex]V_{ab}''=I_3'R_{2||1-4}=2V[/tex]
If we consider both batteries:
[tex]V_2=I_2R_2=V_{ab}=V_{ab}'+V_{ab}''=5V[/tex]