A) Refer to the diagram on “Speed Control of a Shunt Wound DC Motor.

Suppose the no load voltage V = 90V, R_a + R₁ = 4 ohms, R_sh + R_F = 130 ohms, and the motor runs at a rated speed of 1000 RPM when I_L = 4 amps. What is the back EMF V_B in volts when the motor runs at I_L = 6 amps?

Note: Type a 1-decimal number, rounded off to the nearest 0.1

B) How do you know that the compound motor provides good speed control at the no-load condition?

1) The torque speed curve is flat near zero torque. This means that small changes in load do not appreciably change the speed.

2) The torque speed curve is flat near zero torque. This means that large changes in load do not appreciably change the speed.

3) The torque speed curve has a large slope near zero torque. This means that large changes in load lead to very small changes in speed.

4) The compound motor runs at slow speeds when heavily loaded.

5) Items (1) and (4)

C) You are designing a new emergency brake mechanism for an automobile featuring one of the following DC motors. Which one would you choose?

1) Permanent magnet motor

2) Brushless motor

3) Servomotor

4) Compound wound motor

5) Torque motor

(D) Suppose you are building a machine where the timing sequence of two drive axes requires that they operate at precisely the same speed. What type of motor would you select: AC or DC and why?

1) You select identical DC motors because controlling frequency input gives simple and precise speed control

2) You select identical AC motors because highly accurate and reliable AC speed controllers can be bought for very cheap prices

3) You select identical DC motors because controlling voltage input gives simple and precise speed control

4) You select identical AC motors because the variance of torque and speed specs on NEMA specified motors is very small

5) It doesn’t matter whether you select an AC or a DC motor. The cost of supplying accurate speed control for either type of motor is the same.

Instructions:    Mark the sentences for correct punctuation and capitalization.   

1.      The president elect unfortunately changed her plans postponing her

visit until April 10-12.

2.      George Washingtons home Mount Vernon is located near Alexandria

Virginia

3.      The Society for Technical Communication STC holds an annual

summit which is hosted by one of its large chapters however last year the summit was held on-line.

4.      Host cities have included: Boston, New York, Chicago; Atlanta, Las

Vegas, Dallas, Minneapolis—St Paul and Denver.   

5.      Did I hear you say I will not go

6.      Stimulus loans-although in small amounts $10,000-$20,000—have

provided some relief to small business owners.

7.      Will the audience please rise

8.      When will this exercise end was the question on everyones mind.

9.      He packed for the editing conference. Red, green and blue pens, 5x7, 8½x11 and 11 x 14 paper, and a portable high speed paper shredder, that runs on batteries which he forgot to pack.

A widget machine makes 900 units if it runs continuously for 8 hours. Every 10 hours, the machine requires 30 minutes of maintenance during which no units are made. What is the productivity of the machine?

The following table consists of cash flow data for a selected ten days.

A. Calculate the variance of net daily cash flows.

B. Assuming a lower limit of $300, a transaction cost of $15, and an annual interest rate of 8 percent, what is the upper limit and what is the return point using the Miller-Orr model?

QUESTION 40

1. When you plan the test runs for a program, you should do all but one of the following. Which one is it?

   	a.	list the invalid entries and unexpected user actions for each test run
   	b.	list the expected exceptions for each test run
   	c.	list the expected results for each test run
   	d.	list the valid entries for each test run

1.5 points   

QUESTION 41

1. Which of the following for loops could you use to iterate the data in a vector named days if you need to be able to work with iterators within the loop?

   	a.	for (auto p: days) { ... }
   	b.	for (int i = 0; i < days.size(); ++i) { ... }
   	c.	for (auto iter = days.begin(); iter != days.end(); ++iter) { ... }
   	d.	all of the above

1.5 points   

QUESTION 42

1. Code Example 8-2
   1. /* This application displays a student's score after a 5-point curve */
   2.
   3. void display_info(string fname, string lname, int score) {
   4.      cout << "Hello, " << fname << ' ' << Lname;
   5.      cout << "Your score on this is " << score;
   6.      score = score + 5;
   7. }
   8.
   9. int main() {
   10.     string first, last;
   11.     int score = 0;
   12.     cout << "first name: ";
   13.     cin >> first;
   14.     cout << "last name: ";
   15.     cin >> last;
   16.     cout << "score: ";
   17.     cin >> grade;
   18.     display_info(first, last, score);
   19. }

   (Refer to Code Example 8-2.) What is the error in the main() function?

   	a.	The cin statement on line 17 stores the input in an undefined variable named grade.
   	b.	The cin statement on line 17 does not define grade as an int.
   	c.	The function call on line 18 should send in fname and lname as arguments, not first and last.
   	d.	There are no errors in main().

1.5 points   

QUESTION 43

1. Which of the following techniques could you use to define an array of strings named products with 5 elements?

   	a.	const int size = 5; array<string, size> products;
   	b.	array<string, 5> products;
   	c.	int size; cin >> size; array<string, size> products;
   	d.	all of the above
   	e.	a and b only

1.5 points   

QUESTION 44

1. Which type of error lets the program run but produces the wrong results?

   	a.	user
   	b.	runtime
   	c.	syntax
   	d.	logic

1.5 points   

QUESTION 45

1. How would you modify the following enumeration to change the underlying enumerator type to char?
   enum class Suit {
       diamonds = 'd',
       hearts = 'h',
       clubs = 'c',
       spades = 's'
   };

   	a.	enum class : char Suit {     diamonds = 'd',     hearts = 'h',     clubs = 'c',     spades = 's' };
   	b.	enum class Suit : char {     diamonds = 'd',     hearts = 'h',     clubs = 'c',     spades = 's' };
   	c.	enum class Suit char {     diamonds = 'd',     hearts = 'h',     clubs = 'c',     spades = 's' };
   	d.	enum class Suit {     char diamonds = 'd',     char hearts = 'h',     char clubs = 'c',     char spades = 's' };

1.5 points   

QUESTION 46

1. If you don’t specify the values of the enumerators in an enumeration, they are stored as

   	a.	sequential int values starting at 1
   	b.	sequential int values starting at 0
   	c.	sequential char values starting at 'A'
   	d.	sequential char values starting at 'a'

1.5 points   

QUESTION 47

1. Given the following code, if the user worked 45 hours at $10.00/hour, the output is as shown below.
   1. int main() {
   2.      double hours, rate, pay;
   3.      cout << "How many hours did you work? ";
   4.      cin >> hours;
   5.      cout << "What is your hourly rate? ";
   6.      cin >> rate;
   7.      if (hours > 40 && rate < 15)
   8.          pay = (40 * rate) + (hours - 40 * rate * 1.5);
   9.      else
   10.         pay = hours * rate;
   11.     cout << "Your pay is: $" << round(pay * 100) / 100;
   12. }
   Output:
   Your pay is: $-105
   Which line should be changed to fix this logic error?

   	a.	change line 8 to: pay = (40 * rate) + ((hours - 40) * rate * 1.5);
   	b.	change line 7 to: if (hours > 40 || rate < 15)
   	c.	change line 2 so hours and rate are integer values instead of floating-point values
   	d.	change line 11 to: cout << "Your pay is: $" << ceil(pay * 100) / 100;

1.5 points   

QUESTION 48

1. Which of the following techniques could you use to initialize an array of ints named ages so its 4 elements contain the values 57, 33, 45, and 0?

   	a.	array<int, 4> ages { 57, 33, 45, 0 };
   	b.	array<int, 4> ages { 57, 33, 45 };
   	c.	array<int, 4> ages; ages[0] = 57; ages[1] = 33; ages[2] = 45; ages[3] = 0;
   	d.	all of the above
   	e.	a and c only

1.5 points   

QUESTION 49

1. Which of the following is not an advantage of using a for loop and subscripting to iterate the data in a container?

   	a.	You can easily skip elements by changing the loop criteria.
   	b.	It uses a counter variable that can be useful for tasks such as displaying a number for each element.
   	c.	It’s available to all containers.
   	d.	You can get the value of an element without dereferencing an iterator that points to it.

How manyn-digit binary strings have at least two 0s?

The Gourmand Cooking School runs short cooking courses at its small campus. Management has identified two cost drivers it uses in its budgeting and performance reports—the number of courses and the total number of students. For example, the school might run two courses in a month and have a total of 61 students enrolled in those two courses. Data concerning the company’s cost formulas appear below:

For example, administrative expenses should be $3,600 per month plus $44 per course plus $7 per student. The company’s sales should average $900 per student.

The company planned to run four courses with a total of 61 students; however, it actually ran four courses with a total of only 55 students. The actual operating results for September appear below:

Required:

Prepare a flexible budget performance report that shows both revenue and spending variances and activity variances for September. (Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance). Input all amounts as positive values.)

For each of the following two-samples t-tests (problems 1-6): (a) Determine if a F test for the ratio of two variances is appropriate to calculate for the context. If it is appropriate, conduct the analysis and report the result. Include what statistical conclusion you should draw from the analysis (i.e., whether you should conduct a pooled-variance t-test or an unequal-variances t-test). (b) Identify the most appropriate t-test to conduct for the situation/data given. Don’t forget to consider if the context requires one/two-tail tests. (c) Provide a statistical and practical interpretation of your findings.

2. An article appearing in The Exponent, an independent college newspaper published by the Exavier Student Publishing Foundation, reported that the average American college student spends one hour (60 minutes) on Facebook daily. But you wonder if there is a difference between males and females. You select a sample of 60 Facebook users (30 males, 30 females) at Baker University. The time spent on Facebook per day (in minutes) for these 60 users is stored in FacebookTime. Is there evidence of a difference in mean time spent on Facebook per day between males and females? (Use a 0.05 level of significance)

For each of the following two-samples t-tests (problems 1-6): (a) Determine if a F test for the ratio of two variances is appropriate to calculate for the context. If it is appropriate, conduct the analysis and report the result. Include what statistical conclusion you should draw from the analysis (i.e., whether you should conduct a pooled-variance t-test or an unequal-variances t-test). (b) Identify the most appropriate t-test to conduct for the situation/data given. Don’t forget to consider if the context requires one/two-tail tests. (c) Provide a statistical and practical interpretation of your findings.

2. An article appearing in The Exponent, an independent college newspaper published by the Student Publishing Foundation, reported that the average American college student spends one hour (60 minutes) on Facebook daily. But you wonder if there is a difference between males and females. You select a sample of 60 Facebook users (30 males, 30 females) at Baker University. The time spent on Facebook per day (in minutes) for these 60 users is stored in FacebookTime. Is there evidence of a difference in mean time spent on Facebook per day between males and females? (Use a 0.05 level of significance)

show the t-test and p-value results with all work of the two groups performance (y)