Corrections to Problems and Solutions in the “FE Exam Review” Section of the Beer and Johnston, Statics/Dynamics Website

Prepared by

Stephen F. Felszeghy Emeritus Professor of Mechanical Engineering

California State University, Los Angeles

As I mentioned in the FE exam review class, several problems in the “FE Exam Review” section, of the Beer and Johnston, Statics/Dynamics Website, have errors in their statements, solutions, and multiple-choice answers. Some of the mistakes in the solutions are quite serious because they involve the application of wrong physical principles. In this document, I list the errors and corrections. To this end, I have divided the remainder of the document into two parts: Part 1 and Part 2. Part 1 of the document lists all the online problems and solutions from Chapters 11 through 17, and Chapter 19. We didn’t cover Chapter 18 in the FE exam review class. When you access the problems online, the problems appear in a random order and without numbers. For this reason, in Part 1, I list all the problems, and I assign numbers to them in a manner similar to that used for problems in the textbook. Part 2 of the document lists the errors and corrections according to the problem numbering scheme laid out in Part 1.

Part 1

“FE Exam Review”

Online Problems and Solutions

Problem 11.1

Problem 11.2

Problem 11.3

Double-click

here to edit text.

Problem 11.4

Problem 11.5

Problem 11.6

Problem 12.1

Problem 12.2

Problem 12.3

Problem 12.4

Problem 12.5

Problem 12.6

Problem 12.7

Problem 13.1

Problem 13.2

Problem 13.3

Problem 13.4

Problem 13.5

Problem 13.6

Problem 13.7

Problem 14.1

Problem 14.2

Problem 14.3

Problem 14.4

Problem 14.5

Problem 14.6

Problem 15.1

Problem 15.2

Problem 15.3

Problem 15.4

Problem 15.5

Problem 15.6

Problem 16.1

Problem 16.2

Problem 16.3

Problem 16.4

Problem 16.5

Problem 16.6

Problem 17.1

Problem 17.2

Problem 17.3

Problem 17.4

Problem 17.5

Problem 17.6

Problem 19.1

Problem 19.2

Problem 19.3

Problem 19.4

Problem 19.5

Problem 19.6

Part 2

Errors and Corrections

Problem11.1“counterclockwise”shouldread“clockwise”“clockwise”shouldread“counterclockwise”Problem11.5Thecorrectsolutiongivestheanswer,

€

−500i −100j,m/s2.Thisanswerisnotshownamongthemultiplechoices.Problem12.3Thecorrectsolutiongivestheanswerof(d),not(a).Problem13.1ThisproblemshouldbemovedtoChapter17!Thecorrectsolutiongivestheanswer,4.37m/s.Thisanswerisnotshownamongthemultiplechoices.Problem13.2Thecorrectsolutiongivestheanswer,‐16.67m/s.Thisanswerisnotshownamongthemultiplechoices.Problem13.3Thecorrectansweris(c),not(d).Thesolutioniscorrect!Problem13.5Thecorrectsolutiongivestheanswer,136kN.Thisanswerisnotshownamongthemultiplechoices.Problem13.6Thevalueforkinthefigureshouldread“0.1kN/mm”,insteadof“1kN/mm”.Iftheeffectofgravityisincluded,thenthesolutiongivestheanswer,1.902m/s.Problem14.2Theblueballisnotatrestfollowingthecollision!Problem14.4Thecorrectsolutiongivestheanswer,0.815m.Thisanswerisnotshownamongthemultiplechoices.Also,theblueballisnotatrestfollowingthecollision!Problem14.5Thedimension“1.414D”inthefigureshouldread“0.707D”.

Problem14.6Thecorrectsolutiongivestheanswer,0.425N.Thisanswerisnotshownamongthemultiplechoices.Problem15.1Answer(d)iscorrectascalculated,not(c).Problem15.6Thecorrectsolutiongivestheanswer,

€

−4i −1.25j ,m/s2.Thisanswerisnotshownamongthemultiplechoices.Problem16.2Themassoftheflywheelisnotgiven.Theflywheelhasa20‐kgmass,andhastheshapeofauniformdisk.Problem17.3Thecorrectsolutiongivestheanswer,0.0420rad/s.Thisanswerisnotshownamongthemultiplechoices.Problem17.4Thecorrectsolutiongivestheanswer,16,379m/s.Thisanswerisnotshownamongthemultiplechoices.However,theanswerisphysicallyunrealistic,implyingthatthespecifiedangleof30°ismuchtoolarge!Problem17.5Allthenumbersandunitsofthemultiple‐choiceanswersarewrong!Thecorrectsolutiongivestheanswer,4.87rad/s.Problem19.5Thesolutiongivestheanswer,0.346m/s.Thisanswerisnotshownamongthemultiplechoices.Problem19.6Thesolution,continuedfromProblem19.5above,givestheanswer,4m/s2.Thisanswerisnotshownamongthemultiplechoices.