DEVELOPMENT OF AN INTERACTIVE FREE BODY DIAGRAM ASSISTANT FOR - PDF - PDF
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DEVELOPMENT OF AN INTERACTIVE FREE BODY DIAGRAM ASSISTANT FOR BIOMECHANICS Robert J. Roselli1, Bryan Cinnamon2, Patrick Norris1, Sean P. Brophy1, Derek Eggers2 and Jerry Brock2 1Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 2Ntara, Inc, Johnson City, TN. Motivation: Newton's Laws: ΣF = 0 ΣM = 0 are deceptively simple. Identifying all forces and couples in a particular problem can be challenging!! Free Body Diagram Tool used to identify all forces and couples in a problem Illustration What reactions keep the gymnast in this position? Constructing a FBD Step 1: Isolate body Constructing a FBD W Step 2: Indicate External Forces Constructing a FBD W N Step 2: Indicate External Forces Constructing a FBD W N Step 3: Indicate Applied Couples Constructing a FBD W C N Step 3: Indicate Applied Couples Solution Statics ? Forces = 0 ? Momentsc = 0 y h X ?F = 0 = N - W ? Mc = 0 = 20cm*W - C If all forces and couples are not placed on the diagram, then the solution will be incorrect. Free Body Diagram Assistant • Asynchronous web tool • Macromedia Flash 5 • SQL Server for data storage/retrieval Free Body Diagram Assistant Three Components • Student interaction & feedback • Authoring tool • Administrative Area Student Interaction with FBD Assistant Authoring Tool Administration Area Add a User View Sessions Session Information and Diagnostics Is the FBD Assistant Effective? FBD Assistant Survey strongly agree 5 4 3 2 1 strongly The free body diagram tool helped me Once I saw the final solution I was able to I usually remember to include moments disagree understand how to solve a free body figure out what I had incorrect and I knew and couples diagram why. Performance Before and After use of the FBD Assistant 7 * 6 5 * Average Score 4 * * 3 2 1 0 pulley 4a-1 4a-2 man 4b-1 club 4b-2 golfer Pre Post * p<0.05, paired t-test E.S. = .45-.82 Summary • We have developed an online tool that guides students in the development of free body diagrams. • Students respond favorably to the FBD Assistant. • FBD Assistant is effective in improving construction of free body diagrams. Future Plans for Improving the FBD Assistant • Improve Authoring Tool • Use CAPE for advanced remediation & tracking • Develop a library of practice problems.