Conference Session

Mechanics Division Technical Session 2

Collection

2019 ASEE Annual Conference & Exposition

Authors

John A. Mirth, Saint Cloud State University

Tagged Divisions

Mechanics

mastery of course information. a. Ability to engage current topics (88 pts available) Assessments Daily Homework (88 pts) b. Ability to sustain expertise on past topics (126 pts available) Assessments Daily Review Problems (46 pts) Review Week Problems (80 pts) 3. Students will be able to apply computational tools to calculate and verify solutions to mechanics problems. (105 pts available) Assessments Computational lab assignments (60 pts) Computational analysis of design problems (45 pts) 4. Students will demonstrate the ability to

Conference Session

Mechanics Division Technical Session 5

Collection

2019 ASEE Annual Conference & Exposition

Authors

Brian P. Self, California Polytechnic State University, San Luis Obispo; Sonya Dick, California State Polytechnic University, San Luis Obispo; Jay Tyler Davis II, California Polytechnic State University, San Luis Obispo; Bradley Wash, California Polytechnic University, San Luis Obispo

Tagged Divisions

Mechanics

-varying nature of dynamic systems. Some teaching strategies to overcome thisinclude computer simulations and the use of videos, but only a few researchers have utilizedmotion analysis systems or other instrumentation in their dynamics courses.One of the goals of our recent Keck Foundation grant is to incorporate our motion analysissystem into courses in engineering and kinesiology. To date, we have utilized three differentassignment versions in our dynamics course: (a) allowing students to select their own artefact foranalysis, (b) supplying six specific artefacts for analysis, and (c) interfacing with a Kinesiologyclass on motor learning to provide “expert” engineering advice on performance measures ofnovice jugglers versus advanced jugglers.We

Conference Session

Mechanics Division Technical Session 4

Collection

2019 ASEE Annual Conference & Exposition

Authors

James Giancaspro P.E., University of Miami; Diana Arboleda, University of Miami

Tagged Divisions

Mechanics

rope), but moment is a relatively abstract concept to them.Additional frustration is encountered due to the term "moment" since it conflicts with thestudents' prior knowledge from their physics course. There, they encountered the concept ofmomentum. This prior knowledge often leads to two misconceptions: 1. Since momentum is formed from the root "moment" with the addition of a derivational morpheme (-um), students assume that the concept of momentum presented in Physics is the same as the concept of moment in Physics. 2. The term moment has different meanings: (a) brief period of time, or (b) effect produced by a force acting at a distance on an object. Since "moment" is homographic and students have

Conference Session

Mechanics Division Technical Session 4

Collection

2019 ASEE Annual Conference & Exposition

Authors

Yufeng Hu P.E., Western Michigan University; Javier Martin Montefort P.E., Western Michigan University; Matthew Cavalli P.E., Western Michigan University

Tagged Divisions

Mechanics

Cumulative GPA Cumulative GPA (a) Traditional section (b) Redesigned section Figure 1: Distribution of student cumulative GPA in the two sectionsStudent performance in StaticsTable 4 shows the comparison of the passing rate of the traditional section and the redesignedsection of Statics. The redesigned section has a moderately higher passing rate compared withtraditional section. Table 4 Comparison of Statics passing rate Section Total no. of students No. of students get C or better

Conference Session

Mechanics Division Technical Session 6

Collection

2019 ASEE Annual Conference & Exposition

Authors

Ron Averill, Michigan State University; Sara Roccabianca, Michigan State University; Geoffrey Recktenwald, Michigan State University

Tagged Divisions

Mechanics

thesestudents into a course that requires mastery. Among other reasons, it is likely that they have notdeveloped proper study habits or the skills necessary to review and correct their work during anexamination. To account for this, multiple opportunities were provided on each of the midtermexams. For each of the midterm exams, the final score was the sum of the best scores in eachsection (described below) from any of the exam attempts. There was only one attempt on thefinal exam, which had a similar structure as the midterm exams.In version 1 of the assessment model, three attempts (A, B and C) at each exam were offered.There were four midterm exams, so a total of twelve exams plus the final exam were offeredduring the semester. With three chances to

Conference Session

Mechanics Division Technical Session 1

Collection

2019 ASEE Annual Conference & Exposition

Authors

Eric Constans, Rose-Hulman Institute of Technology; Karl Dyer, Rowan University; Shraddha Sangelkar, Rose-Hulman Institute of Technology

Tagged Divisions

Mechanics

A&M University. She completed the B. Tech (2008) in Mechanical Engineering from Veermata Jijabai Technological Institute (V.J.T.I.), Mumbai, India. She taught for 5 years at Penn State Behrend prior to joining Rose-Hulman. c American Society for Engineering Education, 2019 A New Method for Teaching the Fourbar Linkage to Engineering StudentsAbstractThe fourbar linkage is one of the first mechanisms that a student encounters in a machinekinematics or mechanism design course and teaching the position analysis of the fourbar hasalways presented a challenge to instructors. Position analysis of the fourbar linkage has a longhistory, dating from the 1800s to the

Conference Session

Mechanics Division Technical Session 3

Collection

2019 ASEE Annual Conference & Exposition

Authors

Ghada M. Gad, California State Polytechnic University, Pomona; Giuseppe Lomiento, California State Polytechnic University, Pomona; Yu Sun, California State Polytechnic University, Pomona

Tagged Topics

Diversity

Tagged Divisions

Mechanics

.  Voice Recognition. Voice is the main approach to support user interaction with the app. The Audio app uses Google’s Voice Input AI to conduct real-time voice recognition and text to speech features. The recognition works in both online and offline mode, so the app can still function in the conditions when the Internet connection is not available.  Natural Language Processing. Most of the quiz questions are multiple-choice questions, where students only need to answer simple choices such as “A”, “B”, “C” and “D”. This type of answers can be captured and supported easily because it does not have much complicated language context. However, we also plan to support the questions that require brief

Conference Session

Mechanics Division Technical Session 6

Collection

2019 ASEE Annual Conference & Exposition

Authors

Jeffrey A. Davis, Grant MacEwan University; Shelley Lorimer, Grant MacEwan University

Tagged Divisions

Mechanics

, determine the pin reactions at A, B, C, D, and E. There is a pin at A and a roller at E. Dimensions and angles are provided. Show all of your working including FBDs needed.Figure 1: Questions used for Exam 1–Straight Frame (Left) and Exam 2–Inclined Frame (Right) Assignments and seminars in the course reinforced this solution methodology by assessing thestudents’ problem solving process and final answer as opposed to their final answer only. Forsolving frames specifically, students were taught to look at a variety of ways to set up and solvethe problem: both as a whole and by breaking the problem down into parts. It is important to notethat the results of the study may be specific to the teaching method described above

Conference Session

Mechanics Division Technical Session 1

Collection

2019 ASEE Annual Conference & Exposition

Authors

Jeffrey C. Hayen, Oregon Institute of Technology

Tagged Divisions

Mechanics

have previously taught statics and dynamics coursesover a sustained period of time are likely familiar with the practices listed below, which addressthe conventional evaluation of the appropriate moments-of-forces/couples equation that governsthe rotational behavior of a rigid body:  Statics: Moments may be evaluated about axes through any selected point in space, which is typically on, in, or nearby the rigid body of interest.  Dynamics: Moments should be evaluated about either (a) axes through the mass center of the body, or (b) a fixed axis about which the body is constrained to rotate (if applicable).This article presents another option for evaluation of the moments-of-forces/couples equation forthe targeted case of dynamics. The

Conference Session

Mechanics Division Technical Session 4

Collection

2019 ASEE Annual Conference & Exposition

Authors

Diana A. Chen, University of San Diego; Sarah Wodin-Schwartz, Worcester Polytechnic Institute

Tagged Divisions

Mechanics

this pack? The backpack has dimensions 25”x13”x8”. Assume A = 6 lbs, B = 10 lbs, C = 3 lbs, D = 5 lbs, and neglect the weight of the backpack itself. Make other assumptions as needed. https://herpackinglist.com/2013/09/how-to-pack-a-backpack/ Reflect: 1. The backpack is held up by your shoulders and hips. Which of these should support the more weight to maximize efficiency? 2. The video says to tighten the compression straps once the pack is on to stabilize and streamline the pack. Where might these straps be placed, and how should they shift the load of the pack? 3. Does the expert way to pack the backpack align with how you would pack it given

Conference Session

Mechanics Division Technical Session 3

Collection

2019 ASEE Annual Conference & Exposition

Authors

Amir Hedayati Mehdiabadi, University of Illinois, Urbana-Champaign; Rebecca A. Atadero, Colorado State University; Daniel W. Baker Ph.D., P.E., Colorado State University; Anne Marie Aramati Casper, Colorado State University

Tagged Topics

Diversity

Tagged Divisions

Mechanics

Paper ID #25744The Effects of Infusing Diversity and Inclusion into a Design Problem in En-gineering Mechanics: StaticsMr. Amir Hedayati Mehdiabadi, University of Illinois, Urbana-Champaign Amir Hedayati is an Assistant Professor at Organization, Information & Learning Sciences department at College of University Libraries & Learning Sciences at University of New Mexico. He received a Ph.D. in Human Resource Development from University of Illinois in 2018. He has a B.S. degree in Computer Engineering from Sharif University of Technology and an M.B.A. degree from University of Tehran. He has presented his research

Conference Session

Mechanics Division Poster Session

Collection

2019 ASEE Annual Conference & Exposition

Authors

Aaron Price Barnett; Nick M. Safai, Salt Lake Community College

Tagged Divisions

Mechanics

Paper ID #25469Board 101: Project Based Learning for a Mechanical Engineering Major Stu-dent: The Sustainability of Internal Combustion Engines (Student Poster)Mr. Aaron Price Barnett Aaron Barnett is currently a sophomore at Salt Lake Community College studying Material Science En- gineering with a minor in Chemistry. His academic focus includes renewable energy and sustainable materials. As well as helping shape a new generation of engineers and scientists to continue improving the world.Dr. Nick M. Safai, Salt Lake Community College Dr. Nick M. Safai is an ASEE Fellow. He has been an ASEE officer and member for the past

Conference Session

Mechanics Division Technical Session 3

Collection

2019 ASEE Annual Conference & Exposition

Authors

Narasimha Siddhanti Malladi, Malladi Academy

Tagged Divisions

Mechanics

. W1 C W2 A α β θ B System Space Digram Solution to Timoshnko Problem as in reference [2] with comments in square brackets bythis paper's author. Minor modifications are made due to changes in format. α Y θ β SAB θ SAB R1 X W1 W2

Conference Session

Mechanics Division Technical Session 6

Collection

2019 ASEE Annual Conference & Exposition

Authors

Phillip Cornwell, Rose-Hulman Institute of Technology; Amir H Danesh-Yazdi, Rose-Hulman Institute of Technology

Tagged Divisions

Mechanics

dynamic setting and should bediscouraged at the introductory level. Examples of this poor habit were found in each of theStatics books. One example is shown below (Sample Problem 3/2 from Meriam and Kraige[14]). Example: Calculate the tension T in the cable which supports the 1000-lb load with the pulley arrangement shown in Figure 1(a). Each pulley is free to rotate about its bearing, and the weights of all parts are small compared with the load. Figure 1. (a) Problem statement figure, (b) Meriam and Kraige’s FBDs, (c) Better FBDsMeriam and Kraige’s FBDs for this problem are shown in Figure 1(b). Note that the 1000-lbforce is the tension in the cable AD. In Figure 1(c), which includes a better FBD, the pulley A,the cable and the load

Conference Session

Mechanics Division Technical Session 3

Collection

2019 ASEE Annual Conference & Exposition

Authors

Andrew R. Sloboda, Bucknell University

Tagged Divisions

Mechanics

2 ft statement and y any accompanying figures for 1.5 ft BuAC = a r AC each problem. b = - 0.1218i + 0.6910 j - 0.7125 k Figure 1 shows the arrangement 3 ft of the prompts and the

Conference Session

Mechanics Division Technical Session 4

Collection

2019 ASEE Annual Conference & Exposition

Authors

Josue Njock Libii, Purdue University Fort Wayne

Tagged Topics

Diversity

Tagged Divisions

Mechanics

quantities of rug pads. You are given a piece of material that is purported to prevent slippage. Test and evaluate the claim that the material of which the rug pads are made prevents slipping. B. Design three tests: Test 1. Test the carpet, or some other material, without the pad under it. Test 2. Test the same materials (rugs, or others) with pads under them but without other loads on the pad than the weight of the “rug”. Test 3. This test is similar to test 2, except that there is a load on the carpet. Test at least five different magnitudes of loads. C. Collection of data. Determine and collect the data that you need in each test. D. Interpretation of data. Interpret the data that you collected. E. Evaluation of

Conference Session

Mechanics Division Technical Session 1

Collection

2019 ASEE Annual Conference & Exposition

Authors

Bidhan C. Roy, University of Wisconsin, Platteville

Tagged Divisions

Mechanics

activities undertaken by the student.Unfortunately, in recent years, extensive use of solution manuals and replication of answers fromthe solution manual without any understanding has been a major hurdle in the learning process ofthe students. Blind faith in the solution manual rather their own abilities to solve problemsnegatively impacts a student’s conceptual understanding of the principles of Dynamics andtherefore impedes their critical thinking ability. This is a nationwide phenomenon [1], [2], [3]and some important reasons has been traced to – (a) students who are employed outside schoolfind less time in their studies, (b) lack of mathematical and analytical skills discourages studentsfrom trying on their own, and (c) instant gratification of

Conference Session

Mechanics Division Technical Session 4

Collection

2019 ASEE Annual Conference & Exposition

Authors

Eric Davishahl, Whatcom Community College; Todd R. Haskell, Western Washington University; Jill Davishahl, Western Washington University; Lee Singleton, Whatcom Community College; Wade H. Goodridge, Utah State University

Tagged Divisions

Mechanics

students at WCC and WWU in fall2018. The correct answer is in boldface. NA indicates students did not answer the question. Difficulty Point-biserial Item Description Index Correlation A B C D NA 1 2D position vector components 0.85 0.31 2 7 0 50 0 from length and angle given on annotated photo 2 Vector addition in 2D from point 0.58 0.50 0 23 34 2 0 labels on annotated photo 3 Visualizing direction of cross 0.69 0.63 1 5 12 41 0 product in 2D from position and force vectors referencing

Conference Session

Mechanics Division Technical Session 6

Collection

2019 ASEE Annual Conference & Exposition

Authors

Amir Danesh-Yazdi, Rose-Hulman Institute of Technology; Yi Wu, Penn State Erie, The Behrend College; Oladipo Onipede Jr., Penn State Erie, The Behrend College

Tagged Divisions

Mechanics

andconfusing for students. One manner in which we have attempted to simplify the sheer number ofmathematical approaches that the students need to consider in our Vibrations course is toconsider any linear SDOF and MDOF problem using a state-space approach, in which only fourmatrices,  A ,  B  , C  ,  D  , need to be obtained from the system in order to fully evaluate the 1 response and the associated properties (natural frequencies, damping ratios, mode shapes, etc.) ofthe system, regardless of the initial conditions or forcing function [1]. While we have found thisapproach to be effective in our instruction of the course, we have commonly encounteredscenarios in which the students have

Conference Session

Mechanics Division Technical Session 2

Collection

2019 ASEE Annual Conference & Exposition

Authors

Anna K. T. Howard, North Carolina State University

Tagged Topics

Diversity

Tagged Divisions

Mechanics

class. (seeFigure 2) The proportion of B grades increased by 21%, the proportion of D grades decreased by36%, and the proportion of F grades decreased by 62%.A Pearson Chi2 Test of Independence showed strong evidence that an association does existbetween students' final grades in Statics and the design phase they experienced (X2 [10, n=2,412]= 20.84, p = 0.016). The number of students in Phase 3 who earned a B is significantly higher(z=2.31, p

Conference Session

Mechanics Division Technical Session 5

Collection

2019 ASEE Annual Conference & Exposition

Authors

Hamed Samandari, Miami University; Banafsheh Seyed-Aghazadeh, Miami University

Tagged Divisions

Mechanics

. (a) (b) (c) (d)Figure 1. Schematic of commonly used engineering mechanisms a) rock crasher b) transfer mechanism c) mechanism to turn over cartons d) reciprocating saber saw [15]The first year data was used as the baseline for the study. During the second year, PBL approachwas used to introduce students to design project. Students worked on a series of projects on aself-paced schedule and reported their work at the end of semester as a group presentation. At thebeginning of semester, students were allowed to self-select team members (four members perteam). In the third year implementation of PBL, project management

Conference Session

Mechanics Division Technical Session 5

Collection

2019 ASEE Annual Conference & Exposition

Authors

Anna K.T. Howard, North Carolina State University

Tagged Divisions

Mechanics

measures after they saw the deformation of the J-beam in Figure 7.Figure 7: Screen shot from J-beam bending animationStudents were able to see on the screen thatthe points A and B had moved closer to thelocked midsection of the beam. After themoment of inertia demonstrations, studentsvolunteered that the shorter AC would bendmore than the longer BD. This animationdemonstrated that points A, B, C, and Dwhich were all in plane when the J-beam wasundeformed were no longer all planarafterwards. This experience gave somecontext to the homework question shown inFigure 8 where students were asked tocalculate the product of inertia for the beam. Figure 8: Homework problem to find product ofSuch an animation

Conference Session

Mechanics Division Technical Session 5

Collection

2019 ASEE Annual Conference & Exposition

Authors

Amitabha Ghosh, Rochester Institute of Technology

Tagged Divisions

Mechanics

performthe integration, simplify the ratio incorrectly, or, evaluate the constant incorrectly, which wouldbe revealed from the given choices. If the class performance was not up to expectations, studentswould still get the opportunity to improve their score on the question by resubmitting the quiz[18]. If the class size is small enough, alternate and accurate assessment may be performed usinga stand-alone quiz as the Quiz No. 3 shows. As always, a prompt return of the original quiz isnecessary so that students can relearn the missed topic over the approaching weekend (seeAppendix B for a note sent to students).The relevant flow viscosity questions are preceded by understanding of dry friction first indynamics and then (with the help of strength

Conference Session

Mechanics Division Technical Session 2

Collection

2019 ASEE Annual Conference & Exposition

Authors

Mohammad Reza Hassanzadeh Gorakhki, Colorado State University; Daniel W. Baker Ph.D., P.E., Colorado State University; Stephanie F. Pilkington, Colorado State University

Tagged Divisions

Mechanics

instruction (with < 10% active learning during the class session) and tworelated homework problems per topic. For the flipped sessions, students watched recordedlectures before class. Each topic had a <20 minute overview video plus an example video whichwere recorded lectures from the same instructor and then edited to present online. Students wereminimally introduced to the in-class activity before dividing into 2-4 person groups to createMindstorms Lego systems to manipulate and evaluate rigid-body motion systems. Two teachingassistants and one grader helped students during Section A flipped session and the instructor anda teaching assistant answered students’ questions during Section B flipped session. As part of thein-class activity, each

Conference Session

Mechanics Division Technical Session 5

Collection

2019 ASEE Annual Conference & Exposition

Authors

David Allen Evenhouse, Purdue University, West Lafayette; Nick Stites, Purdue University, West Lafayette; Amy K. Dunford, Purdue University, West Lafayette; Rohit Kandakatla, Purdue University, West Lafayette; Jeffrey F. Rhoads, Purdue University, West Lafayette; Edward J. Berger, Purdue University, West Lafayette; Jennifer Deboer, Purdue University, West Lafayette

Tagged Divisions

Mechanics

. Education + Training, 56(2/3), 105–121.[3] Means, B., Toyama, Y., Murphy, R., Bakia, M., & Jones, K. (2009). Evaluation of evidence- based practices in online learning: A meta-analysis and review of online learning studies. Washington, D.C.[4] Phillips, J. A., Schumacher, C., & Arif, S. (2016). Time Spent, Workload, and Student and Faculty Perceptions in a Blended Learning Environment. American Journal of Pharmaceutical Education, 80(6), 1–9.[5] Pombo, L., Loureiro, M. J., & Moreira, A. (2010). Assessing collaborative work in a higher education blended learning context: strategies and students’ perceptions. Educational Media International, 47(3), 217–229.[6] Boelens, R., De Wever, B., & Voet, M. (2017). Four key

Conference Session

Mechanics Division Technical Session 1

Collection

2019 ASEE Annual Conference & Exposition

Authors

Shuh-Jing Ying P.E., University of South Florida

Tagged Divisions

Mechanics

OPERATORSDefinition of Rotation Operator The notations used in the equations are as follows: bold letters represent vectors, adouble arrow on the top of a letter indicates a dyad or dyadic. A pair of vectors written in adefinite order, such as ij, is called dyad and a linear combination of dyads is known as a dyadic.Now, consider that a position vector r is rotated with respect to vector n by angle β to r’. Theangle β is measured in the plane perpendicular to n, containing the ends of vectors r and r’ inthat plane as shown in Fig. 1. Let a be a vector with the direction of n and the magnitude of thecomponent of r along n, so that 𝐚𝐚 = 𝐧𝐧 ( 𝐫𝐫 ∙ 𝐧𝐧 )Let b and c be vectors in the circular plane, which is the top view of Fig. 1a looking

Conference Session

Mechanics Division Technical Session 2

Collection

2019 ASEE Annual Conference & Exposition

Authors

Rania Al-Hammoud P.Eng., University of Waterloo; Chloe Gibson

Tagged Divisions

Mechanics

topics. A rating ofone corresponded to possessing little knowledge of the topic, while a rating of ten demonstrateda high level of understanding. Upon review of the responses, it was revealed that the averagerating was a seven or eight for each of the concepts. A complete list of concepts included in thesurvey can be found in Appendix B. Some examples of these included representing a force usinga vector, the relationship between an arch's shape and the loads that it carries, and the mostefficient distribution for reinforcements along a silo. The fairly high average response shows thatstudents feel confident in their knowledge of the course topics. While it is likely in part due tothe videos, this data on its own is not entirely reflective of the

Conference Session

Mechanics Division Technical Session 6

Collection

2019 ASEE Annual Conference & Exposition

Authors

Ashraf Badir P.E., Florida Gulf Coast University; Jiehong Liao, Florida Gulf Coast University; Galen I. Papkov, Florida Gulf Coast University; Robert O'Neill P.E., Florida Gulf Coast University

Tagged Divisions

Mechanics

(Table A1 in the Appendix). Algebra and geometry/trigonometrywere included since instructors were noticing that students had difficulty with solvingsimultaneous equations as well as identifying sine versus cosine of angles or triangle ratios whenresolving forces into components. The prerequisite requirement to enter this course is a lettergrade of C or above in Calculus 1 and Physics 1. However, College Algebra is a prerequisite forPre-Calculus, which is a prerequisite for Calculus 1. Trigonometry is included in Pre-Calculus,whereas students may have taken Geometry in high school. Figure 8 shows the proportion ofstudents who earned an A, B, or C in each foundational subject. Moderately positive correlationswere observed between the letter grades

Conference Session

Mechanics Division Technical Session 3

Collection

2019 ASEE Annual Conference & Exposition

Authors

Julian Ly Davis, University of Southern Indiana; Tom McDonald, University of Southern Indiana; Jenna Kloosterman, University of Southern Indiana

Tagged Divisions

Mechanics

Investigation Of Online Homework: Required Or Not Required?,” Contemp. Issues Educ. Res. – Second Quart., vol. 6, no. 2, pp. 189–199, 2013.[11] V. Berardi, “The Impact of Using Randomized Homework Values on Student Learning,” vol. 11, no. 2, pp. 4–17, 2011.[12] J. Dillard-Eggers, “Evidence On The Effectiveness Of On-Line Homework,” Coll. Teach. Methods Styles J., vol. 4, no. 5, 2008.[13] D. J. Doorn, S. Janssen, and M. O’Brien, “Student Attitudes and Approaches to Online Homework,” Int. J. Scholarsh. Teach. Learn., vol. 4, no. 1, 2010.[14] D. B. Smithrud and A. R. Pinhas, “Pencil-Paper Learning Should Be Combined with Online Homework Software,” J. Chem. Educ., vol. 92, no. 12, pp. 1965–1970, 2015.[15] J. L. Davis and T. N

Conference Session

Mechanics Division Technical Session 2

Collection

2019 ASEE Annual Conference & Exposition

Authors

Benjamin Keith Morris, University of Georgia; Siddharth Savadatti, University of Georgia

Tagged Divisions

Mechanics

); CVLE2710:Numerical Methods for Engineers and ENGR3160:Fluid Mechanics taughtduring Spring 2016, and ENGR2120:Engineering Statics taught during Fall 2016. These coursesare referred to as Numerical, Fluids and Statics respectively throughout this paper. Classdays/duration, enrollment and grading weights of these courses are listed in Table 1.All three courses were taught in an identical flipped format that required pre-class, in-class, andpost-class work as shown in Figure 1 for almost every class (exceptions were the first class of thesemester and some classes following the tests). Students (a) watched pre-class videos and solvedpre-class problems before attending a class (these were their pre-class activities), (b) startedsolving in-class problems