1. EGR 105 Foundations of Engineering I Fall 2007 – week 3 Project 1

2. Bungee Jumping Briefly, some theory The e -notebook In-class experimentation

4. Initially Potential energy only is present center of gravity of the jumper W = mg h

5. During Free Fall Fall distance d, 0 ≤ d ≤ L Some potential energy is converted to kinetic, so v = velocity d

6. During the Stretch Now the cord starts to store energy since d > L Energy stored in the cord equals the integral of the force f (stretch) d stretch = d – L original cord length L (without stretch)

7. At the Bottom, distance d 0 Velocity v is now zero, so We could solve for d 0 if we knew f v = 0 d0d0 L GOAL !!

8. Models for Cords Hooke’s Law – linear: More realistic model: –Increasing in x –f (0) = 0 –Limit for large x Stretch x Force f (x)

9. Assignment #3 – As a Team Take measurements of cord characteristic: –Force scales –Weights –Rulers Team homework: start your e -notebook –Sheet 1 – general team info –Sheet 2 – words and numbers summarizing today’s measurements –E-mail the spreadsheet to me

10. Sample e -notebook