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SOLUTIONS MANUAL

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

Chapter 1: What Do Engineers Do? Solution Manual 1. Draw a conceptual sketch of your computer. Identify the keyboard, screen, power source, and information storage devices using arrows and labels.

Note: Eventually we will show you (if you don’t know already) how to draw a decently formatted sketch on your computer. Meanwhile this crude representation will suffice!

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

2. Draw a conceptual sketch of a football and identify all the components (stiches, cover, bladder, inflation port, etc.) using arrows and numbers as in Figure 1.1.

1 – inflation port 2 – leather cover panel 3 – rubber bladder (internal) 4 – stitches (for gripping) 5 – sewn seam between cover panels

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

3. Draw a conceptual sketch of a ballpoint pen. Identify all the components with arrows and labels as in Figure 1.2 of this chapter. The name of ballpoint pen's parts and components No.

Name

No.

Name

refill

clip

ball

barrel shell

point

cap

socket

clip screw

slot

clip screw

eyelet

connector

refill tube

button spring

ink

ratchet spring

grease

retracting spring

cartridge

plunger

plastic lube

trapped spring

point

ratchet frame

barrel

liner

--see http://www.ball-penmanufacturers.com/pen_show_110_The_name_of_ballpoint_pen's_parts.htm (Hong-Li Pen manufacturing Co, Ltd.)

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

4. Check this exploded view of a table. Identify and label all the components.

Table top

Frame

Legs

Mortise & Tenon

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

5. Check this exploded view of a box. Identify and label all the components.

Lid Hinges End Brackets

Bottom Sides End

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

6. Repeat Example 1.3 using the NSPE Code of Engineering Ethics. Solve using the Engineering Ethics Matrix.

Example 1.3: An Ethical Situation The following scenario is a common situation faced by engineering students. Read it and think about how you would respond. What are your ethical responsibilities? You and your roommate are both enrolled in the same engineering class. Your roommate spent the weekend partying and did not do the homework that is due on Monday. You did the homework, and your roommate asks to see it. You are afraid he or she will just copy it and turn it in as his or her own work. What are you ethically obligated to do? a. Show your roommate the homework. b. Show the homework but ask your roommate not to copy it. c. Show the homework and tell the roommate that if the homework is copied, you will tell the professor. d. Refuse to show the homework. e. Refuse to show the homework but offer to spend time tutoring the roommate.

Ethical Decision Matrix Canons

Option (a)

Option (b)

Option (c)

Option (d)

1. Hold paramount the safety, health, and welfare of the public. 2. Perform services only in the area of your competence. 3. Issue public statements only in an objective and truthful manner.

Not applicable.

Not applicable

Not applicable.

Not applicable

Not applicable.

Are you a competent tutor? Not applicable.

Violates this 4. Act for each canon if employer or client as homework is faithful agents or not to be trustees. shared. Violates this canon if sharing 5. Avoid deceptive homework is acts. considered cheating by instructor..

Same as option (a).

OK.

Same as option (a).

OK.

Option (e)

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

6. Conduct themselves honorably.

Same as above. Same as option (a).

Same as option (a).

OK.

Of course, it may be possible to find a code of professional ethics that will lead to a contrary opinion to another code, but as per the solution in the text for Example 1.3, this code of professional ethics favors the same solutions, namely d & e.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

7. Repeat Example 1.4 using the Five Cornerstones of Ethical Behavior. Solve using the Engineering Ethics Matrix

Example 1.4 You are a civil engineer on a team designing a bridge for a state government. Your team submits what you believe to be the best design by all criteria, at a cost that is within the limits originally set. However, some months later the state undergoes a budget crisis. Your supervisor, also a qualified civil engineer, makes design changes to achieve cost reduction that he or she believes will not compromise the safety of the bridge. You are not so sure, though you cannot conclusively demonstrate a safety hazard. You request that a new safety analysis be done. Your supervisor denies your request on the grounds of time and limited budget. What do you do?

Cornerstone 1. Do what you say you will do.

a) Go along with the decision You did not say you would do this.

b) Appeal to higher management You did not say you would do this.

c) Quit your job

You did not say you would do this. You may appeal Not to higher applicable. management

d) Write your e) Call a state newspaper representative reporter You did not You did not say you would say you do this. would do this. Violates this Violates this cornerstone. cornerstone.

2. Never divulge information given to you in confidence.

Not applicable

3. Accept responsibility for your mistakes.

Not applicable

Not applicable.

Not applicable. Not applicable.

Violates this cornerstone of you believe your supervisor is lying. Not applicable.

Not applicable.

Maybe, if you think someone is lying.

Not applicable.

Not applicable. Not applicable.

4. Never become involved in a lie.

5. Never accept gifts that compromise your ability to perform in the best interests of your organization.

Maybe, if you think someone is lying.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

Again, it’s roughly the same conclusion as per Example 1.4 in the text: Your best bet is to go over your immediate supervisor’s head and bring your dilemma to higher management.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

8. It is the last semester of your senior year and you are anxious to get an exciting electrical engineering position in a major company. You accept a position from company A early in the recruiting process, but continue to interview hoping for a better offer. Then your dream job offer comes along from company B. More salary, better company, more options for advancement, it is just what you have been looking for. What should you do? a. Just don’t show up for work at company A. b. Send a letter to A retracting your job acceptance with them. c. Ask company B to contact company A and tell them you won’t be working for them. d. Reject the offer from company B and work for company A anyway. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful agents or trustees Avoid deceptive acts

a.) Just don’t show up Yes-no risks

b.) Send letter retracting Yes-no risks

c.) Ask B

Does not apply

Does not apply-not yet employee

Does not Does not apply-not yet apply-not employee yet employee

Nodeceptive

Yes – is not deceptive

No-unless you initially made it clear

Conduct themselves honorably

d.) Reject B

Yes-no risks Yes-no risks

No –potentially deceptive if B doesn’t do it Nopassing the buck

Does not apply-not yet employee

Yes

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

…

to A that you would retract if offered by B

The “best” answer is to reject the offer from Company B; however, the real message here is to be upfront with company A while provisionally accepting their offer saying you reserve the right to go to Company B.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

9. A company purchased an expensive computer program for your summer job with them. The license agreement states that you can make a backup copy, but you can only use the program on one computer at a time. Your senior design course professor would like you to use the program for your senior design project. What should you do? a. Give the program to your professor and let him/her worry about the consequences. b. Copy the program and use it because no one will know. c. Ask your supervisor at the company that purchased the program if you can use it at school on your senior project. d. Ask your professor to contact the company and ask for permission to use the program at school. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful agents or trustees Avoid deceptive acts Conduct themselves honorably

a.) Give to Prof

b.) Copy and use

c.) Ask supervisor

d.) Ask Prof to contact

Yes- no risk

Yes-no risk

Does not apply

No-cheats company

No- cheats company

Yes

No – is deceptive

Yes

You need to do c) and d).

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

10. You are attending a regional conference along with five other students from your institution. The night before the group is scheduled to return to campus, one of the students is arrested for public intoxication and is jailed. Neither he nor the other students have enough cash for bail, and he doesn’t want his parents to know. He asks you to lend him the organization's emergency cash so that he doesn't have to spend the night in jail; he'll repay you as soon as his parents send money. What should you do? a. Lend him the money since his parents are wealthy and you know he can repay it quickly. b. Tell him to contact his parents now and ask for help. c. Give him the money, but ask him to write and sign a confessional note to repay it.. d. Tell him to call a lawyer since it’s not your problem. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful agents or trustees Avoid deceptive acts

a). Lend

c). Money and note

d). Tell not your problem

Yes-no risk

b). Tell: contact parents Yes-no risk

Yes-no risk

Does not apply

No-unless money was previously authorized for bail

Yes

No-unless money was previously authorized for bail

Yes

Yes-if you show note to organization.

Yes

No if you are hoping to put money back without telling organization

Yes

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

Conduct themselves honorably …

Noallowing your concern for friend to override your duty to organization

Yes

Yes – an attempt, though flawed, to combine duties to friend and organization

Yes – although as a matter of personal ethics, telling a friend that his problems are not yours may be unacceptable, this is not a violation of professional ethics

So you should consider telling him to call his parents and/or a lawyer.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

11. You are testing motorcycle helmets manufactured by a variety of your competitors. Your company has developed an inexpensive helmet with a liner that will withstand multiple impacts but is less effective on the initial impact than your competitor’s. The Vice President for Sales is anxious to get this new helmet on the market and is threatening to fire you if you do not release it to the manufacturing division. What should you do? a. Follow the vice president’s orders since he/she will ultimately be responsible for the decision. b. Call a newspaper to “blow the whistle” on the unsafe company policies. c. Refuse to release the product as unsafe and take your chances on being fired. d. Stall the vice president while you look for a job at a different company. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful agents or trustees

Avoid deceptive acts Conduct

a). Follow order

b). Blow whistle

c). Refuse to release

d). Stall

No Would knowingly put public at risk

Yes avoids putting public at risk

No-leaves public at risk

Yes

No- press relations is not your area of expertise

Yes

Yes – no public statement made

Yes - but only if you are sure of your facts

Yes- no public statement made

Yes-no public statement made

Maybe depends on whether supervisor intends to deal with risk in another manner Yes – is not deceptive Yes

No- as an agent, you are expected to get permission before speaking to press

Yes

No- you owe your employer a truthful interpretation of your actions

Yes – is not deceptive Yes

Yes- is not deceptive

No-stalling is deceptive

Yes

No-hiding

Yes

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

themselves honorably …

your true views is dishonorable

Refuse to release the defective article should at least be a major option to consider even though it may have a serious effect on your career.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

12. Paul is employed at Bluestone Ltd. as a manufacturing engineer. He regularly meets with vendors who offer to supply Bluestone with needed services and parts. Paul discovers that one of the vendors, Duncan, like Paul, is an avid golfer. They begin comparing notes about their favorite golf courses. Paul says he's always wanted to play at the Cherry Orchard Country Club, but since it is a private club, he's never had the opportunity. Duncan says he's been a member there for several years and that he's sure he can arrange a guest visit for Paul. What should Paul do?1 a. Paul should accept the invitation since he has always wanted to play there. b. Paul should reject the invitation since it might adversely affect his business relationship with Duncan. c. Paul should ask Duncan to nominate him for membership in the Club. d. Paul should ask his supervisor if it’s OK to accept Duncan’s invitation. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful agents or trustees

a). Accept

b). Reject

d). Ask supervisor

Yes-no risk

c). Ask Duncan to nominate Yes-no risk

Yes-no risk

Does not apply

Yes, if you have consulted company ethics guidelines and determined

Yes

Yes-no risk

Yes

Extracted from TEACHING ENGINEERING ETHICS, A CASE STUDY APPROACH, Michael S. Pritchard Editor, CENTER FOR THE STUDY OF ETHICS IN SOCIETY WESTERN MICHIGAN UNIVERSITY. http://ethics.tamu.edu/wpcontent/uploads/sites/7/2017/04/ethics.tamu_.edu_pritchar_golfing.pdf ] 1

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

Avoid deceptive acts Conduct themselves honorably …

that it’s ok; otherwise, no Yes – is not Yes – is not deceptive deceptive Yes

Yes

Yes- unless you suggest to Duncan that if he says no, he won’t get the order

Yes

You have a lot of latitude here so you can pick almost any action or a combination.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

13. Some American companies have refused to promote women into positions of high authority in their international operations in Asia, the Middle East, and South America. Their rationale is that business will be hurt because some foreign customers do not wish to deal with women. It might be contended that this practice is justified out of respect for the customs of countries which discourage women from entering business and the professions. Some people feel that such practices are wrong and that gender should not to be used in formulating job qualification. Further, they believe that customer preferences should not justify gender discrimination. Present and defend your views to your class or course instructor on whether or not this discrimination is justified.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

14. Marvin Johnson is environmental engineer for one of several local plants whose water discharges flow into a lake in a flourishing tourist area. Included in Marvin's responsibilities is the monitoring of water and air discharges at his plant and the periodic preparation of reports to be submitted to the Department of Natural Resources. Marvin has just prepared a report that indicates that the level of pollution in the plant's water discharges slightly exceeds the legal limitations. However, there is little reason to believe that this excessive amount poses any danger to people in the area; at worst, it will endanger a small number of fish. On the other hand, solving the problem will cost the plant more than $200,000. Marvin's supervisor says the excess should be regarded as a mere technicality, and he asks Marvin to adjust the data so that the plant appears to be in compliance. He explains: "We can't afford the $200,000. It would set us behind our competitors. Besides the bad publicity we'd get, it might scare off some of tourist industry." How do you think Marvin should respond to his supervisor’s request? a) Do what his supervisor says. b) Ask his supervisor to join him in discussing this with his supervisor’s boss. c) Do not do what his supervisor says. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful

a). Do what his supervisor says Yes-no risks

b). Ask his supervisor to join in discussing the issue Yes-no risks

Yes

Does not apply

Noexposes company to legal action

Yes

c). Do not do what his supervisor says Yes-no risks

Yes

Does not apply

No - simple disobedience, even if justified, is

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

agents or trustees Avoid deceptive acts

No. Yes – Deceptive to is not customer deceptive

Conduct themselves honorably …

No – is putting oneself above the law

Yes

not the action of a faithful agent No –potentially deceptive if boss thinks he’s obeying Maybe, depending on how done

Here the solution is clear – get his supervisor’s boss involved b).

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

15. Derek used to work for Company A, which is a small computer firm that specializes in developing software for management tasks. Derek was a primary contributor in designing an innovative software system for customer services. This software system is essentially the "lifeblood" of the firm. The small computer firm never asked Derek to sign an agreement that software designed during his employment there becomes the property of the company. However, his new employer did. Derek is now working for Company B, which is a much larger computer firm. Derek's job is in the customer service area, and he spends most of his time on the telephone talking with customers having systems problems. This requires him to cross reference large amounts of information. It now occurs to him that by making a few minor alterations in the innovative software system he helped design at the small computer firm, Company A, the task of cross referencing can be greatly simplified. On Friday, Derek decides he will come in early Monday morning to make the adaptation. However, on Saturday evening he attends a party with two of his old friends, you and Horace. Since it has been some time since you have seen each other, you spend some time discussing what you have been doing recently. Derek mentions his plan to adapt the software system on Monday. Horace asks, "Isn't that unethical? That system is really the property of your previous employer." "But," Derek replies, "I'm just trying to make my work more efficient. I'm not selling the system to anyone, or anything like that. It's just for my use -- and, after all, I did help design it. Besides, it's not exactly the same system -- I've made a few changes." What should be done about this situation?2 a) Derek should go ahead and make the adaptation. b) Derek should suggest to his boss a meeting with the other company to discuss use of the program. c) Derek should drop the idea. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your

a). Make the b). Suggest a adaptation meeting

c). Drop the idea

Yes-no risks Yes-no risks

Yes-no risks

Yes

Adapted from Teaching Engineering Ethics, A Case Study Approach, Michael S. Pritchard, editor, Center for the Study of Ethics in Society Western Michigan University: http://ethics.tamu.edu/wpcontent/uploads/sites/7/2017/04/ethics.tamu_.edu_pritchar_property.pdf 2

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful agents or trustees Avoid deceptive acts

Conduct themselves honorably …

Does not apply

Maybe- may Yes expose current employer to possible suit or bad publicity No- while Yes – is not possibly deceptive legal, the action is deceptive (implies new company developed idea) No – (see Yes deceptive)

Does not apply

No- an employee should pursue good ideas No employee is hiding a good idea

Yes

b) is the best course.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

16. Jan, a professional engineer on unpaid leave, is a graduate student at a small private university and is enrolled in a research class for credit taught by Professor Dimanro at the University. Part of the research being performed by Jan involves the use of an innovative geothermal technology. The university is in the process of enlarging its facilities, and Professor Dimanro, a member of the university’s building committee, has responsibility for developing a request to solicit interested engineering firms. Professor Dimanro plans to incorporate an application of the innovative geothermal technology into the new facility. Professor Dimanro asks Jan to serve as a paid consultant to the university’s building committee in reviewing proposals. Jan’s employer will not be submitting a proposal and is not averse to having Jan work on the proposal reviews. Jan agrees to serve as a paid consultant. Is it a conflict of interest for Jan to be enrolled in a class for credit at the university and at the same time serve as a consultant to the university? 3 a) Jan should assume a conflict of interest and drop the idea. b) Jan should request a legal opinion as to the legality of this service. c) Jan should go ahead and serve without inquiring further. Options Canons Hold paramount the safety, health and welfare of the public. Perform services only in the area of your competence Issue public statements only in an objective and truthful manner Act for each employer or client as faithful agents or trustees

a). Drop idea

b). Request legal opinion

c). Go ahead

Yes-no risks Yes-no risks

Yes-no risks

Yes

Yes, if he acknowledges his connection to university

Yes- has consulted with employer

Yes

yes

3 Adapted from NSPE Board of Ethical Review Case No. 91-5

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 1

Avoid deceptive acts Conduct themselves honorably

Yes

Yes, if he acknowledges his connection to university Maybe, depending on whether he or university hopes to gain from the connection (e.g., unjustified positive opinion, unjustified higher grade)

Note: as is evident from the matrix, the answer to this question depends on detailed legal knowledge as to whether being a student and paid consultant simultaneously constitutes a conflict of interest.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

Chapter 2: Elements of Engineering Analysis Solution Manual 1. Sketch the isometric plate below and add the following dimensions: Height = 5.0 cm, Length = 40.0 cm, Width = 20.0 cm. The diameter of the hole is 10 cm and it is centered 15.0 cm from the front.

Solution:

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

2. Sketch and complete the orthographic drawing below.

Solution:

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

3. Sketch the top, left, and front views of the object below.

Solution

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

Need: 5.00 gallon can = ___mouthfuls Know: Conversions 1.00 ft = 12.0 inches & 1.00 gallon = 0.134 ft3. How: Units analysis. Solve: 5.00 gallon = 5.00  0.134 [gallons][ft3/gallon] = 0.670 ft3 = 0.670  12.03 [ft3][in/ft]3 = 1.158  103 in3 = 1.158  103/0.900 [in3][mouthfuls/in3] = 1.286 = 1.29  103 mouthfuls.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

5. Identify whether you would perform the following unit conversions by definition, by conversion factors, by geometry, or by scientific law: a) How many square miles in a square kilometer? b) How many microfarads in a farad? c) What is the weight on Earth in N of an object with a mass of 10. kg? d) How many square miles on the surface of the earth? Need: For each part, conversion is ___________ (state whether definition, conversion factor, geometry, or scientific law) Know: Basic concepts of conversion factors, geometry and scientific laws. Also that the diameter of the Earth1 is 12,756 km How: For conversions use units method Solve: a) How many square miles in a square kilometer? Units conversion: 1.000 mile = 1.609 km; 1 square mile = 12  1.6092 [mile]2 [km/mile]2 = 2.589 km2. b) How many microfarads in a farad? Units conversion: 1 farad = 1 million microfarads = 1  106 [F] [microF/F] = 106 microF. c) What is the weight on Earth in N of an object with a mass of 10.0 kg? Scientific law: W = mg = 10.0  9.81 [kg][m/s2] = 980. N. d) How many square miles on the surface of the earth? Geometry + units conversion: Geometry: Surface area of a sphere: D2. (Note: engineers prefer ‘diameter’ to ‘radius’ in many instances since it is easier to measure a diameter than to directly measure a radius). 1.00000 mile = 1.60934 km. A =   D2 = 3.14159  12,7562/1.609342 [km]2[mile/km]2 = 1.9737  108 mile2.

1. E.g., http://hyperphysics.phy-astr.gsu.edu/hbase/solar/soldata2.html#c3

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

6. An acre was originally defined as the amount of area that an oxen team could plow in a day. Suppose a team could plow 0.040ha per day, where a hectare is 104m2. There are 1609 meters in a mile. How many acres are there in a square mile? Need: Square mile = ________ acres. Know: Conversion factors: 1609 m/mile, 104 m2/hectare. A team could plough 0.040ha/day = 1 acre/day. Thus 1.0 hectare = 2.5 acres. How: Method of units Solve: 1 square mile = 1.000  16092 [mile]2[m/mile]2 = 2.589  106 m2 = 2.589  106/104 [m]2 [hectares/m]2 = 2.589  102 [hectares] = 2.589  102  2.5 [hectares][acres/hectare] = 647 = 600 acres (since the team plows 0.4 hectares, only known to one significant digit.)

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

7. There are 39 inches in a meter. What is the area in the SI system of the skin of a spherical orange that is 4.0 inches in diameter? Need: Area of orange skin = ________ m2. Know: Conversion factors: 39 inches/m; How: Method of units and a spherical orange whose surface area is D2 Solve: Skin area of orange =   4.02 [in]2 = 50.3/392 [in]2[m/in]2 = 3.3  10-2 m2

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

8. There are 39 inches in a meter. What is the volume in the Engineering English system of a spherical apple that is 10. cm. in diameter? Need: Volume of apple = ________ in3. Know: Conversion factors: 39 inches/m and 100 cm/m. How: Method of units and assume a spherical apple whose volume is D3/6. Solve: Volume of orange =   10.3/6 [cm]3 = 524/1003 [cm]3[m/cm]3 = 5.23  10-4  393 [m3][in/m]3 = 31. in3

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

9. Suppose the ranch in Example 2.3 was a circle instead of a square. Using the same financial information ($320,000 available funds, $10.103 a mile for fence, and $10.104 per square mile land cost), what would be the diameter of the ranch? Need: Diameter of circular ranch Know: $320,000 available funds, $10,000 a mile for fence, and $100,000 per square mile land cost How: Use sketch to visualize situation and then make appropriate mathematical model. Solve: Cost of fence = $10,000  D Cost of area = $100,000  D2/4 Total cost = $10,000  D + $100,000  D2/4 = $320,000 Hence diameter given by 10 D2/4 + D – 32 = 0 Solution using Excel, “Goal seek” equation solver

A B Use "goal seek" First guess at answer in miles 23 24

See Excel help

C D E Equation using Update using Updated 1st guess goal seek Equation

1.000

-21.004

A B C Use "goal seek" First guess at Equation using 1st guess answer in miles 23 24

See Excel help

=10*PI()*B24^2/4 + PI()*B24-32

1.828

-7.54E-05

D Update using goal seek

E Updated Equation

1.82838777060369

=10*PI()*D24^2/4 + PI()*D24-32

Diameter = 1.83 miles

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

10. The great physicist Enrico Fermi used to test the problem-solving ability of his students at the University of Chicago by giving them the following problem: How many piano tuners are there in the city of Chicago? (Assume the population of Chicago is 5 million people.) (Plausible answers 50–250 tuners.2)

Need: ___________ Piano tuners in Chicago. Know: Population of Chicago is 5.  106 people. How: Estimate 1 person in 100 Chicagoans owns a piano and gets it tuned yearly. A standard working year is about 200 days. Assume tuner can tune a piano in 2 hours and, with travel, he/she can tune 3 pianos per day. Use the method of dimensional analysis to aid in the solution. Solve: Except for unemployed piano tuners, the required tunings = the number of tuners available. (5. 106/100.)  1 [Chicagoans][piano/Chicagoan][tunings/piano yr] = 50,000 [piano tunings/year].  50,000/200 [piano tunings/year][year/working day] = 250 [piano tunings/day] # tuners = 250/3 [piano tunings/day] [tuners day/tuning] = 83.3 = 80 tuners. If think the assumptions are poor just use the spreadsheet program blow and change them to reasonable ones you prefer. A 1 Population 2 Pianos 3 Freq. tuning 4 Tuned/yr 5 Tuned/day 6 Tuners

5000000 =B1*E1 1 per yr =B2*B3 per yr =B4/E2 per day =B5/E3

Fraction pianos Tuning days Tuned/day/tuner

=1/100 200 3

See http://www.grc.nasa.gov/WWW/K12/Numbers/Math/Mathematical_Thinking/fermis_piano_ tuner.htmS. 2

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

11. Of all the rectangles that have an area of one square meter, what are the dimensions (length and width) of the one that has the smallest perimeter? Solve by graphing on a spreadsheet. Need: Minimum perimeter ____________ for 1 m2 enclosed rectangle. Know: Perimeter, P = 2  (L + W) where L is length, W is width and area enclosed, A = L  W = 1 m2. How: Set L = 1/W to guarantee 1 m2 area so that P = 2  (1/W + W). Plot P vs. W for minimum. Solve: P minimum if L = W = 1.00 m. B

Perimeter, m

L, m P, m 1 W , m L , m P, m 1 W, m 2 0.50 2.00 5.00 2 =0.5 =1/B2 =2*(B2+C2) 4.9 1.67 3 0.60 4.53 3 =B2+0.1 =1/B3 =2*(B3+C3) 4 0.70 4.26 4 =B3+0.1 =1/B4 =2*(B4+C4) 4.7 1.43 5 0.80 1.25 4.10 5 =B4+0.1 =1/B5 =2*(B5+C5) 4.5 6 0.90 1.11 4.02 6 =B5+0.1 =1/B6 =2*(B6+C6) 4.3 7 1.00 1.00 4.00 7 =B6+0.1 =1/B7 =2*(B7+C7) 4.1 0.91 8 1.10 4.02 8 =B7+0.1 =1/B8 =2*(B8+C8) 9 1.20 4.07 9 =B8+0.1 =1/B9 =2*(B9+C9) 3.9 0.83 2 Area = 1.00 m 10 1.30 10 0.77 4.14 =B9+0.1 =1/B10 =2*(B10+C10) 3.7 11 1.40 0.71 4.23 11 =B10+0.1 =1/B11 =2*(B11+C11) 3.5 12 1.50 0.67 4.33 12 =B11+0.1 =1/B12 =2*(B12+C12) 0.5 1.5 =1/B13 2.0 =2*(B13+C13) 2.5 13 1.60 0.0 0.63 4.45 13 1.0 =B12+0.1 14 1.70 0.59 4.58 14 =B13+0.1 =2*(B14+C14) Length, m =1/B14 15 1.80 0.56 4.71 15 =B14+0.1 =1/B15 =2*(B15+C15) 16 1.90 0.53 4.85 16 =B15+0.1 =1/B16 =2*(B16+C16)

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

12. Suppose you want to make a cylindrical can to hold 0.01 m3 of soup. The sheet steel for the can costs $0.01/m2. It costs $0.02/m to seal circular pieces to the top and bottom of the can and along the seam. What is the cost of the cylindrical can that is least expensive to make? (A: 3 cents/can.) Need: Minimum cost can = __________ $ Know: Volume of cylindrical can is V =  D2/4  h where D is diameter and h is height. Also seal length = h + 2 D. Total area of materials used = 2   D2/4 +  D h. Multiply by respective cost factors. How: Since V = 0.01 m3 is fixed, h = 4V/D2 Solve: Multiply by cost factors and varying with the can’s diameter. Minimum can cost = $0.03 or 3 cents per can. (This big can’s dimensions are 17 cm diameter  44 cm tall). A

1 D, m

h, m Area, m $ material Seal, m $ seal Total $ 0.01 127.32 4.00 0.04 127.39 2.55 2.59

0.03 0.05

3 4

14.15 5.09

1.33 0.80

0.01 0.01

14.34 5.41

0.29 0.11

0.30 0.12

0.07 2.60 0.58 0.01 3.04 0.06 0.07 B C D E F G 2 6 0.09 1.57 0.46 0.00 2.14 0.04 0.05 h, m Area, m 1 D, m $ material Seal, m $ seal Total $ 7 =4*$I$3/(PI()*A2^2) 0.11 1.05 0.38 0.00 =C2*$I$5 1.74 =B2+2*PI()*A2 0.03 0.04 =D2+F2 2 0.01 =0.5*PI()*A2^2+PI()*A2*B2 =E2*$I$4 8 =4*$I$3/(PI()*A3^2) 0.13 0.75 0.33 0.00 =C3*$I$5 1.57 =B3+2*PI()*A3 0.03 0.03 =D3+F3 3 =0.02+A2 =0.5*PI()*A3^2+PI()*A3*B3 =E3*$I$4 4 =0.02+A3 =0.5*PI()*A4^2+PI()*A4*B4 =E4*$I$4 9 =4*$I$3/(PI()*A4^2) 0.15 0.57 0.30 0.00 =C4*$I$5 1.51 =B4+2*PI()*A4 0.03 0.03 =D4+F4 10 0.17 0.44 0.28 0.00 1.51 0.03 0.03 11 0.19 0.35 0.27 0.00 1.55 0.03 0.03 12 0.21 0.29 0.26 0.00 1.61 0.03 0.03 3 13 0.01 m 0.00 can 0.23 0.24 0.26 1.69 0.03 0.04 14 0.25 0.20 0.26 0.00 1.77 0.04 0.04 15 0.27 0.17 0.26 0.00 1.87 0.04 0.04 0.07 16 0.29 0.15 0.27 0.00 1.97 0.04 0.04 0.06 17 0.31 0.13 0.28 0.00 2.08 0.04 0.04 18 0.33 0.12 0.29 0.00 2.19 0.04 0.05 0.05 19 0.35 0.10 0.31 0.00 2.30 0.05 0.05 5

$ total can cost

0.04

H 2 Constants

0.03

3 m can

0.02

0.01 0.02 0.01

4 $/m seal 2

0.01

5 $/m steel

0.1

0.2 Diameter, m

0.3

0.4

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

13. Suppose the mass used in Example 2.5 was increased from 10.0 kg to 20.0 kg, and the wire stretched by twice as much. If the 20.0 kg mass was then used to stretch a 4.00 m piece of the same steel wire, how much would it axially stretch? (Example 2.5: A 2.00 m steel wire is suspended from a hook in the ceiling by with a mass of 10.0 kg that is tied to its lower end; the wire stretches by 15.0 mm under this load. If this same mass is used to stretch a 4.00 m piece of the same steel wire, how much will it stretch?) Need: Stretch = ____ mm for a 4.00 m piece of wire under a 20.0 kg load. Know: Answer to example 3.3: A 4.00 m wire stretched 30.0 mm with a 10.0 kg load. How: We are assuming a plausible relationship that a wire stretches proportional to its length and proportional to its suspended weight. Solve: Since the 4.00 m wire was stretched 30.0 mm with a 10.0 kg load, our proportionality law suggests the same wire will stretch 60.0 mm under a 20.0 kg load. An apparatus for this measurement is called Searle’s apparatus: http://www.scool.co.uk/assets/learn_its/alevel/physics/stress-and-strain/stress-straingraphs/image4.jpg

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

14. Use a spreadsheet analysis to determine the total miles driven by each driver and the average miles driven in each category for the following car renters: Renter Geske Pollack Loth Sommerfeld Thunes Lu

City Miles 35 27 14 12 22 5.0

Suburban Miles 57 11 43 31 16 21

Highway Miles 93 275 159 305 132 417

Need: Average and total miles for drivers Know: Matrix table of data as above How: Spreadsheet analysis Solve:

A 98 Renter 99 100 Geske 101 Pollack 102 Loth 103 Sommerfeld 104 Thunes 105 Lu 106 107 Average miles A 98 Renter 99 100 Geske 101 Pollack 102 Loth 103 Sommerfeld 104 Thunes 105 Lu 106 107 Average miles

B City Miles

C D E Suburban Miles Highway miles Total miles 35 27 14 12 22 5

57 11 43 31 16 21

93 275 159 305 132 417

230

185 313 216 348 170 443

City Miles

C Suburban Miles

D Highway miles

E Total miles

35 27 14 12 22 5

57 11 43 31 16 21

93 275 159 305 132 417

=SUM(B100:D100) =SUM(B101:D101) =SUM(B102:D102) =SUM(B103:D103) =SUM(B104:D104) =SUM(B105:D105)

=AVERAGE(B100:B105)

=AVERAGE(C100:C105)

=AVERAGE(D100:D105)

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

15. Using the renter mileage information given in the previous exercise and the miles per gallon information given in Example 2.7, determine the average gallons per journey segment and average per driver for this set of drivers. Need: Average gallons by segment and by driver Know: Matrix table of data as above plus mpg data How: Spreadsheet analysis Solve: A 117 Renter 118 119 Geske 120 Pollack 121 Loth 122 Sommerfeld 123 Thunes 124 Lu 125 126 Average gallons 127 128 129 130 mpg A 118 119 Geske 120 Pollack 121 Loth 122 Sommerfeld 123 Thunes 124 Lu 125 126 Average gallons

B City miles

C D Suburban Miles Highway Miles 35 27 14 12 22 5

57 11 43 31 16 21

93 275 159 305 132 417

1.6

1.7

8.9

City

Surburbs 18

26 D

35 27 14 12 22 5

57 11 43 31 16 21

=AVERAGE(B119:B124)/B$130

=AVERAGE(C119:C124)/C$130 =AVERAGE(D119:D124)/D$130

9.7 13.4 9.7 14.5 7.8 17.6

Highway

E Av gal/driver

93 275 159 305 132 417

E =B119/B$130+C119/C$130+D119/D$130 =B120/B$130+C120/C$130+D120/D$130 =B121/B$130+C121/C$130+D121/D$130 =B122/B$130+C122/C$130+D122/D$130 =B123/B$130+C123/C$130+D123/D$130 =B124/B$130+C124/C$130+D124/D$130

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

16. Using the technique introduced in Example 2.10, create a spreadsheet graph of the following data for the median annual salaries in dollars for engineers based on years of experience, supervisory responsibility, and level of education.3 Number of Years after BS Degree 5 10 15 25

0 Nonsupervisory B.S. M.S. Ph.D. Supervisory B.S. M.S. Ph.D.

$55,341 — —

$63,649 $79,875 —

$73,162 $86,868 $91,352

$80,207 $90,134 $98,053

$85,116 $97,463 $108,747

$92,74 $110,289 $122,886

— — —

— $99,367 —

$72,632 $109,450 —

$80,739 $110,360 $110,877

$108,747 $113,91 $132,800

$122,886 $117,146 $147,517

Need: Graph of salaries corresponding to table Know: To plot mathematical data, normally need “scatter” plot (with true Cartesian x axis) How: Use “Insert chart” in Excel and follow instructions and/or intuition Solve: Median salary by experience 160,000 140,000

Salary in $

120,000 Non Super, BS Non super, MS

100,000

Non super, PhD Super, BS

80,000

Super MS Super PhD

60,000 40,000 20,000 0 0

Years since BS

These data are from the 2007 report of the Engineering Workforce Commission of the American Association of Engineering Societies (AAES). 3

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

Exercises 17 – 19 involve the following situation: Suppose that the weight of the gasoline in lbf in a car’s gas tank equaled the weight if the car in lbf to the 2/3 power. In other words, if G = gasoline weight in lbf, and W = car weight in lbf, then: G = W2/3. Assume that gasoline weighs 8.0 lbf/gal, and gas mileage, measured in miles/gal or mpg, varies with weight according to the empirical formula: Gas mileage in mpg = (84, 500 lbf)  (Car’s weight in lbf) – 3. mpg 17. What is the fuel usage in miles per gallon of a 3.00 × 103 lbf car? Need: mpg = ___________ for a 3.00  103 lbf car. Know - How: Empirical formula for mpg: Solve: mpg = (84,500 lbf mi/gal)  (1/car’s weight in lbf) -3. miles/gal mpg = (84,500 lbf mi/gal)  (1/car’s weight in lbf) – 3. miles/gal = 84,500/3.00  103 [lbf mi/gal][1/lbf] – 3. [miles/gal] = 25 mpg.

Kosky, Balmer, Keat and Wise: Exploring Engineering, Fifth Edition, Solution Manual, Chapter 2

18. What is the heaviest car that can achieve a range of 600. miles? (A: 3.7 × 103 lbf.) Need: Heaviest car with range of 600. miles. Know: Weight and fuel capacity related by G = W2/3 and a formula relating mpg and vehicle weight. Thus you can have high mpg in a small car, but it also has a small gas tank and vice versa. How: Spreadsheet analysis and graphing range in miles vs. tank capacity in US gallons. Solve: The heaviest car with a 600. mile range weighs 3.69  103 lbf. A 2

lbf/gal

8.0

3 4 wt car, lbf mpg 5 1500 6 7 8 9 10 11 12 13 14 15 16 17 18 800 19 750 20

1750 2000 2250 2500 2750 3000 3250 3500 3750 4000 4250 4500 4750 5000 5250

700 A Range in miles

4 wt car, lbf 5 1500650 6 =A5+250 600 7 =A6+250

lbf gas/car Gal/car Range, miles 53 131 16.4 875 45 145 18.2 824 39 159 19.8 781 35 172 21.5 744 31 184 23.0 711 28 196 24.5 683 25 208 26.0 657 23 219 27.4 634 21 231 28.8 612 20 241 30.2 592 18 252 31.5 574 17 262 32.8 557 16 273 34.1 541 15 283 35.3 526 14 292 36.6 512 13 302 37.8 498

mpg =84500/A5-2.9 =84500/A6-2.9 =84500/A7-2.9

lbf gas/car =A5^(2/3) =A6^(2/3) =A7^(2/3)

Gal/car =C5/$C$2 =C6/$C$2 =C7/$C$2

Range, miles =B5*D5 =B6*D6 =B7*D7

550 500 450

2500

3500 Wt of car in lbf

4500

5500