The Rick ‘n Rollercoaster

EF 151 Final Team Project

26 April 2009

Zac Barton

Bryan Fly

Zach Pendergrass

Project Abstract

This project was designed with the basic idea to make it capable of turning on a light in a

complex and inefficient way. Our team worked diligently to figure out a way to make the

complexities of this device fun, while also trying to maintain a decent minimum time. Our team

spent roughly 22 hours in designing and testing the Rube Goldberg. We encountered many

problems during our testing, some immediately, and others from wear and tear after repeated

tests. After completing several successful runs in a row we decided to settle with what we had

and prepare for the real presentation. Most supplies used, were normal household items that our

team already possessed thus making our project cheaper to build. At times the project was

frustrating, but after the final setup was completed we felt very satisfied and complete.

Introduction

The main objective of our project was to turn on a light, using some of the basic

engineering principles we learned this year. We wanted it to be as inefficient and as complicated

as possible, creating as many steps as possible without going overboard. On the other hand, we

wanted to maintain a decent run time, which was hard to do at times.

Design Process

Our project incorporates several clever mechanisms to activate various elements of the

Rube Goldberg. The device begins by a golf ball being pushed down a tube, the ball strikes a

swinging lever attached to a rope. The rope is on a pulley system that is connected to a domino

that is holding a golf ball from rolling down the custom built track section. This short segment of

track leads into a tunnel made from a rolled up poster. The ball then strikes a series of dominos,

which lead to a loaded mousetrap. When the dominos strike the trigger, a domino is projected up

and strikes a Playdoh cup that is tied to a lever. The lever strikes a golf ball, which forces the ball

to roll down the roller coaster track. The ball strikes another lever which in turn sends another

golf ball zigzagging down a series of tracks. The ball then fly’s onto a custom made switch. The

switch sends an electrical signal to a motor which causes a gear to rotate. The rotating gear is

connected to a rotation switch which turns on a light. The light is used to illuminate our

greatness.

o Materials used:

• K’nex

• Hemp twine

• golf balls

• dominos

• lamp

• battery

• Cat 5 cable

• metal catch can

• Playdoh containers

• On/Off switch

o Key Stats:

• Height of Ball 1= 8 in.

• Height of Ball 2 = 10 in.

• Height of Ball 3= 28in.

• Height of Ball 4= 20in.

• Weight of Golf Ball = 1.62 oz

o Energy Input: Ball one = (32.2)(1.62/16/32.2)(8/12) = .0675 J

• Ball two = (32.2)( 1.62/16/32.2)(10/12) = .0844 J

• Ball three = (32.2)(1.62/16/32.2)(28/12) = .2363 J

• Ball four = (32.2)(1.62/16/32.2)(20/12) = .1688 J

• Spring Energy

• Electrical Energy

• Chemical Energy

o Our project incorporates several of the key areas covered in EF151.

• Projectile motion: is provided from both the mouse trap shooting a domino, and

the golf ball landing on the switch.

• Rotational Motion: The gears turning the light switch on.

• Conservation of Energy: Used both on the ball rolling down the track and also in

the domino setup.

• Torques: Torque is used repeatedly in our levers and also in the light switch.

• Conservation of Linear Momentum: The golf ball strikes several objects most of

which demonstrate conservation of momentum.

Stage 1 Physics: Potential energy ball 1 =

!

mgh = KE

!

V =.0675

1

2

1.62

16

32.2

"

# $

%

& '

(

)

* * * *

+

,

- - - -

V = 6.55 ft/s

Domino accelerates downwards at 32.2 ft/s^2

Stage 2 Physics: Ball has a potential energy of .0844 J this is converted to kinetic energy by

!

mgh = KE .

!

V =.0844

1

2

1.62

16

32.2

"

# $

%

& '

(

)

* * * *

+

,

- - - -

V = 7.37 ft/s.

The ball is traveling at 7.37 ft/s and strikes a series of dominos which lead to a loaded

Mouse trap which projects a domino into a cup causing it to pull a lever.

Stage 3 Physics: Ball is launched with an negligible velocity and has

a potential energy of .2362 J which is sent rolling down a track at a

max velocity of 12.25 ft/s when it strikes yet another lever which

causes ball 4 to begin.

Stage 4 Physics: Our final ball rolls down a custom-built slalom

course until at the bottom the ball flies off the track and hits a switch.

The equations used for this calculation were simple kinematic equations. We measured

the height to be 4 inches off the ground and found the

time to hit the ground by

!

t =2h

g. Using this time and

the balls horizontal velocity of 2.3 ft/s, we were able to

calculate that the switch needed to be roughly 4 inches

away from the tower for the ball to hit it.

Stage 5 Physics: The physics involved in this step include

electrical energy and torque. The torque came from the rotating

motor, which uses the formula of

!

Torque = Fd sin("). The motor

provided enough torque to turn the switch to the on position.

Results

During testing, our project had a high success rate. However, at times we struggled

setting up the dominos and the mousetrap projectile perfectly. During our presentation we

decided to put most of our focus on these weak points in our design. However, we placed too

much attention to these areas and not enough to the rest of it. In turn, our project was successful

in the more complex phases, but failed in the simpler design, that otherwise worked 98% of the

time.

Conclusion

Overall our project was successful, especially for how complex some of the phases were.

The main thing we learned was if an issue, or flaw in the design occurred, we could always find

an alternative route to make it work. It taught us to be creative with our solutions and decisions

on how to set up each phase. Teamwork was crucial in understanding and developing this

project.