Transcript Jimmie Johnson Bungee Jump Model…

Jimmie Johnson Bungee Jumping
(1:23.7 Scale Model)
Alex Falk
Mallory Farrar
Karen Lau
Purpose
 Simulate a bungee
jump by racing star
Jimmie Johnson
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.
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.
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.
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.
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.
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