Some thoughts for teaching engineering statics

Some thoughts for teaching engineering statics Engineering statics is a core technical and gate-keeper course for the mechanical engineering program. During the last several years, it has been noticed that there are two common critical issues for this course: implementation of the parallelogram law and drawing a free-body diagram. Per the engineering statics textbook structure authored by R.C Hibler, after a vector is defined and explained, the parallelogram law is used to conduct vector addition and the reversed parallelogram law is used to resolve a vector into two components. For some students, the implementation of the parallelogram law with the sine law and the cosine law was a big obstacle. They had trouble in implementing the parallelogram law to solve problems in the first two weeks. Some students lost the fight and finally failed due to this obstacle. However, the parallelogram law is completely replaced by the Cartesian vectors' addition and is seldomly used in the rest of course. We tried to jump over the parallelogram law and directly discuss the Cartesian vectors and Cartesian vectors' addition after the vector is defined. It seemed that there was no significant impact on the course without explanation of the parallelogram law. We will continue to try this and cumulate more data about this approach. A thorough understanding of how to draw a free-body diagram is of primary importance for solving problems in engineering statics. But some students have difficulties in drawing a proper free body diagram. They said that they didn't know how to draw a free-body diagram because there were so many different possible situations. They couldn't properly solve engineering statics problems because they couldn't draw a proper free-body diagram. We tackled this issue and listed all five possible types of free-body diagrams for engineering statics courses. For each possible type of free-body diagram, we demonstrated several examples. Because all possible types of free-body diagrams were fully explained, this approach did help some students to overcome the issue of drawing a free-body diagram. This paper will present and explain how to jump over the parallelogram law and directly discuss the Cartesian vectors and Cartesian vectors' addition after the vector is defined. We will also present and explain all possible five types of free-body diagrams to facilitate students to overcome the issue of drawing free-body diagrams.