EGR 105 Foundations of Engineering I

EGR 105 Foundations of Engineering I Fall 2007 – Week 4

EGR105 – Week 4 Topics Project Work – Bungee Cord Characterization Work in Teams - Follow Procedures Outlined in Handout 2 - Mark Cord - Use Test Stand - Add Weights and Measure Resulting Extension - Record Data - Enter Data into Excel Spreadsheet and Do Calculations & Plots

From Last LectureAt the Bottom, distanced0 • Velocityvis now zero, so • We could solve ford0 if weknewF. So we need to characterize bungee cord!(this week) L d0 v = 0

Linear ForceF(s) Cubic Stretchs Typical Models for Cords • Linear Model (Hooke’s Law): • More Realistic Nonlinear Model Cubic Model: But You First Want to Gather Experimental Data on Your Team’s Cord

Wooden Peg Cord lo Loop Knot ? W Bungee Cord TestingCharacterization of F(s) • - Mark Cord • - Use Test Stand • Add Weights • Measure Resulting Extension • - Record Data

Typical Data Expected     ForceF(s)   Most Likely Will Be Nonlinear    

Typical Data in Excel

Assignment # 4 • Enter Data Into Excel Spreadsheet • Calculate Δs and Δs/lo • Make Plot of F versus Δs/lo • Keep Plot on Same Page as Data • Save as teamnumber_4.xls • Turn in hard copy • Due October 4

EGR 105 Foundations of Engineering I