What students ‘know’ about statics: Specific difficulties common among students entering statics

To gain insight into the specific difficulties exhibited by students as they enter Statics, we analyzed studentspsila explanations to concept questions students completed as Warm Up exercises at the beginning of Statics. Students completed four questions as part of three Warm Up exercises on free body diagrams, equilibrium, and equivalence. Students did exhibit some common specific difficulties, and those difficulties are influenced by context. For free body diagrams the most common specific difficulty is the inclusion of an internal force, especially for problems involving ropes. For equilibrium problems students are likely to not consistently apply both force and moment equilibrium. Finally, for equivalence problems students are most likely to try to maintain a specific point of rotation for the body.