1. Jimmie Johnson Bungee Jumping Alex Falk Mallory Farrar Karen Lau (1:23.7 Scale Model)

2. Purpose  Simulate a bungee jump by racing star Jimmie Johnson

3. Overview  Our device is a 1:23.7 scale model of Jimmie Johnson bungee jumping a real-life distance of 15.8 feet. A main inspiration for device components came from a pinball machine “plunger”. A desire to make a sturdy and portable device led to the decision to mount all components on a relatively small piece of MDF board.

4. Work to Potential Elastic Energy 1. Work Input is transferred into a spring by pulling back on a bolt which is part of a “pinball plunger” device. Maximum compression is achieved with a force of 31.5 lbs over a distance of 1.5 inches. A value of 504 lbs per foot was calculated for the spring constant K of the spring in the plunger device.

5. Potential Elastic to Kinetic Energy… and two Collisions 2. When the plunger is released, it strikes a plastic paddle which then rotates around a central bolt. On the opposite end of the paddle, a wooden bumper collides with a golf ball placed at rest at the top of a ramp. Observation of the device reveals that by this point, much of the initial input energy has been lost. This is due to friction occurring in both the plunger device and the paddle. The collision with the bumper gives the golf ball a approximate initial horizontal velocity of 2 feet per second.

6. Gravitational Potential Energy, another Collision 3. The normal force on the ball along the angle of the ramp provides extra acceleration as the ball travels towards the bottom of the ramp, colliding with our model of Jimmie Johnson at approximately 2.9 feet per second.

7. Equilibrium of Gravitational and Elastic Potential Energies 4. The figure falls off the side of the board, but the elastic cord prevents Jimmie from hitting the floor. The system of the figure and the elastic cord reaches equilibrium with Jimmie at a distance of 7 inches below the edge of the board.

8. Conclusions  Problems in design such as “run-away” golf balls and insufficient golf ball velocity were corrected with scrap materials (the golf ball ramp and barrier, respectively)  Jimmie Johnson successfully “bungee jumps” in a majority of test runs