EF 151 Rube-Goldberg
Device
Team Members
Daniel Triplett
 Scott Wherry
 Devin Adams
 Jonathan Brickey
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Materials
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Dominos
PVC Piping
1 Foosball
1 Golf Ball
Duct Tape
Electrical Tape
Glue
2x2 sheet of plywood
Shims
Light Switch
Yellow Light
1 Battery
Overview
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Ball starts down ramp.
Ball falls through PVC piping and hits
dominos.
Dominos fall and hit golf ball on ramp.
Golf ball rolls down ramp and lands in
bottle.
Bottle + golf ball go over edge of table.
Weight of bottle + ball flip switch tied to
bottle.
Light turns on.
Demonstration
Types of Energy Conversions
Given:
 Mass (orange ball) = .005 kg
 Mass (golf ball) = .01 kg
 Mass (dominoes) = .002 kg
 Height of First Ramp = .833 feet
 Height of Second Ramp = .0833 feet
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Energy Conversions
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Part 1:
The orange ball rolls down the ramp, into
the pipe, and out onto the platform.
Calculations: Finding the velocity as the
ball exits the pipe. The point where the
ball exits the pipe is set as the datum.
Conservation of Energy
mgho = .5mv2
(masses cancel out)
(32.2)(.833) = .5v2
v = 7.32 ft/sec
Energy Conversions
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Part 2:
The orange ball collides with the first
domino as it exits the pipe.
Calculations: Finding the velocity of the
domino upon impact of the orange ball,
traveling with a velocity of 5.18 ft/sec.
Conservation of Momentum
m1v1 = m2v2’
(.005)(7.32) = (.002)v2’
v = 18.3 ft/sec
Energy Conversions
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Part 3:
The dominoes complete their chain reaction-rally
and collide with the golf ball place on the top of
the second, smaller ramp.
Assumptions: The dominoes maintain a constant
velocity throughout their rally.
Calculations: Find the velocity of the golf ball
following its collision with the domino.
Conservation of Momentum
m1v1 = m2v2’
(.002)(18.3) = (.01)v2’
v = 3.66 ft/sec
Energy Conversions
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Part 4:
The golf ball rolls down the ramp into the
bottle.
Calculations: Finding the velocity of the
golf ball as it drops into the cup, in turn,
flipping the switch.
Conservation of Energy
mgho + .5mvo2 = .5mvf2
(masses cancel out)
(32.2)(.0833) + .5(3.66)2 = .5vf2
vf = .895 ft/sec
Conclusions
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The project is success in that it performs the function we had in mind. The ball drops
from its initial height, hits the dominoes, which in turn hits a ball that will cause the
lighting of a bulb.
What we learned was that these projects require proper planning, and that you
cannot just leap right into it. I think maybe a better outline/sketch would have been
more beneficial and could have saved more time. This knowledge can help in future
courses and projects.
Also, this project helped us better understand the different types of energy
conservations and how they play out in the real world.
Once we got everything down, we really had only a few problems. The only
real problem was that at first the ball did not drop the bottle off the table, which in
turn did not light the bulb. This was fixed by creating an easier resting point for the
bottle so when the ball landed in the bottle, it dropped with greater ease. And the
only other problem was the setting up of the dominoes. The dominoes can fall easily,
so when setting up we had to be very careful.
The only thing we would have done differently was have a better “pre-game”
plan for the project. At first we kind of jumped into it, but then realized we needed to
write our ideas down. Other than that, the overall project was a success.
References:
We would like to reference Honda. We watched their Super Bowl Rube-Goldberg
commercial to get a good idea of what a Rube-Goldberg project should demonstrate.