Concept for automatic assessment of free body diagrams

Martin Kraska

Technische Hochschule Brandenburg, University of Applied Sciences, Magdeburger Str. 50, 14770 Brandenburg an der Havel, Germany

Abstract

Under the conditions of heterogeneous entry skills of our students we have to augment classical synchronous teaching, be it face-to-face or online, by asynchronous approaches for self-paced individual learning and training. One of these approaches is to provide online exercises with automatic instantaneous feedback.

Therefore, STACK (a system for assessment of mathematics based on a computer algebra) based homework assignments with and without grading stake have been used in the past. The emerging support of JSXGraph from within STACK is the basis for improved exercises, like dynamic sketches, reflecting randomization or students response.

In engineering, a key skill is to communicate using graphs and sketches. Examples from engineering mechanics are free body diagrams or Mohr’s circle for 2D eigenvalue problems.

In principle, it is possible to take interactive input in a JSXGraph applet and evaluate it in the context of a STACK quiz. This has been demonstrated in various places. Some applications like the construction of Mohr’s circle based on given tensor components are quite straightforward to implement.

However, this doesn’t apply to free body diagrams. Providing a general solution for input and evaluation is more involved. The talk discusses basic requirements for such sketches and proposes an author- and user-friendly minimal concept of implementation.