The Berry-GoRound
*Trevor Toll
*Richard Cunningham
*Collin White
*Julie Carrell
*We all agree that this is the final paper for our EF 151 report. This is our
information and we did not take any information from any unauthorized source.
Abstract
The objective for the project was to create a roller coaster using inexpensive and readily
available materials. To begin, we brain stormed and came up with an initial design.
Afterwards, we determined what materials we needed to create the coaster. After
spending ~ $25 on things we needed, we then met and began the building process.
Initially, our first design did not work and we had to re-evaluate what we needed to do.
After deliberation, we came up with a final design. The next time we met, we were able
to finish the coaster. Overall, the coaster took about nine hours to build and lasted sixteen
seconds, which was above our target time of fifteen seconds.
Introduction
In the final team project of the semester in Engineering Fundamentals 151 we were
supposed to create a rollercoaster that would transport an object from the start of the
coaster to the end in 15 seconds. Through this project we were told to work together
demonstrating different ways that engineers would work together and communicate to
others through presentations, spread sheets, and written reports. In order to do this
project we needed to use principles and concepts we learned in Engineering
Fundamentals 151. The rollercoaster that we created must fit into a .5 meter by .5 meter
by .5 meter box when it is folded up. It may unfold to any dimensions necessary, but
must be configured in no more than thirty seconds. The object that is moved along the
track could be anything that could be moved along a track. The only time we may
influence the motion of the ball is at the beginning of the track. The invention must be
original, and the total cost of the project must be under forty dollars.
Design Process
The first time our group met we started come up with different designs for our
rollercoaster. The first idea we had, began rolling down a slope and going through
two consecutive loops. Then it would roll up another slope into a spring to roll back
through the track. We also had ideas about using a spiral somewhere in the track,
which led us to taking out the spring at one end of the track because we knew the
object would not be able to have enough speed to roll back up the spiral. We then
began creating a track starting at .5 meter and rolling down a slope through a loop
and curving around the corner and up a small slope. We then realized that the
object would not be able to gain enough momentum to go much further than this. At
this time we had to start trying to find another design or something we could change
in our design. We decided to add a top to our base that we could add another part of
the track to what we already had. We added the top of the base and decided to use a
spiral that we could sit on the top of our device but could take off and sit inside of
the .5 cubic meter box. For this spiral we started using three pieces of pipe
insulation holding them together with duct tape. We ran into problems the next
time we met because the duct tape did not hold the insulation pieces together at the
connections. After we decided to find another material to use for the spiral, one of
the TA’s helped us create ideas using another ball to roll through smaller plastic
tubing and hitting the lead ball that we originally were going to use for the object to
transfer the energy to it and have it roll through the rest of the track. This idea
worked almost every time we tried it, so we decided to keep this invention and not
change anything about it.
Device
1. Costs:
a. Rubber hose = $8.75
b. Pipe insulation = $1.05
c. Duct tape = $2.00
d. PVC = free (from bind)
e. Funnel = $3.05
f. Wood dowels = 5 x $0.99
g. Ply wood = free (from bind)
h. Lead ball package = $2.00
2. Calculations:
a. For our project, we had to take in several physics factors that we learned
in EF 151. First, for the loop and the spiral we had to take in account
friction and conservation of energy:
𝐹 = 𝜇𝑘𝑁
1
1
1
1
𝑚𝑔ℎ0 + 2 𝑚𝑣02 + 2 𝑘∆𝑥02 + 𝑊𝑖𝑛 = 𝑚𝑔ℎ1 + 2 𝑚𝑣12 + 2 𝑘∆𝑥12 +𝑊𝑜𝑢𝑡
Secondly, we had to consider conservation of momentum for when the
first ball strikes the second ball and falls into the PVC:
𝑚𝑣1 + 𝑚𝑣2 = 𝑚𝑣1′ + 𝑚𝑣2 ′
Finally, we had to consider the velocity of the ball as it fell down the pipe
insulation so it would fall into the funnel.
Results of Testing
My group started working with a bunch of different materials, so that we could
decide which ones worked well with our lead ball. We discovered that the pipe insulation
worked well for our loop, and that clear tubing was not well suited to the lead ball. The
inner diameter of the clear tubing was very inconsistent, causing the ball to stop at
random places. However, we also found out that a small ball bearing ran very smoothly
in the clear tubing, but not in the pipe insulation. We attributed this difference mainly to
friction. The pipe insulation has a lot of friction, while the clear tubing has very little.
The momentum of the heavy lead ball was enough to overcome the friction in the pipe
insulation, while the ball bearing could not run through the loop because it was not heavy
enough to gain the momentum needed. For this reason, we used a section of the clear
tubing with the ball bearing, and a section of pipe insulation with the lead ball. At the
end of the clear tubing, we discovered that the collision between the ball bearing and the
lead ball was elastic enough to push the lead ball into the loop. After we had finished
these main two sections of our roller coaster, we found that we needed it to run a few
seconds longer. So, we tried putting a funnel at the end with a gradually sloped PVC
section to take up the extra few seconds. This worked perfectly, as the lead ball wobbled
back and forth in the funnel before it gradually picked up speed down the incline and
finished the roller coaster on the landing pad.
Conclusions
Our original plan was not successful at all. The ball didn’t have nearly enough
momentum to make it through the first few sections of our planned track. We learned
that friction played a much bigger role than we originally thought. We also learned that
the heavier the ball was, the more momentum it would carry that would allow it to
continue along the track. The main problem we were dealing with was the momentum
killer- friction. Once we found the right combination of ball and track, things ran much
smoothly. Minimizing the energy loss in the conservation of momentum equation was
the key. The only thing that I would do differently would be to draw up a much simpler
starting plan and then go from there. We started with something way too complex and
quite impractical. Also, never underestimate the force of friction!
References
[1] T. Latham, physics and science/technology teacher, Watchung Hills Regional High
School, Warren, New Jersey, available at
http://school.discoveryeducation.com/lessonplans/programs/rollercoaster/#pro
(viewed December 4,2008)
[2] Harris, Tom. “How Rollercoasters Work,” HowStuffWorks, Inc. 1998-2008
http://science.howstuffworks.com/roller-coaster3.htm (viewed December 4, 2008)
Appendix A
Initial chart of rollercoaster parameters:
Rollercoaster material
Placement on coaster and idea
More than 0.5 meter start point
Start of coaster, Maximize potential energy
Two loops
Second part of coaster, Convert potential
energy to kinetic energy
Figure eight loops
Spring
Base of coaster board, part of coaster to eat
up time
End of coaster, to apply elastic potential
energy/ change direction of marble
repeating the two loop and figure eight
framework.
Final chart of rollercoaster parameters
Rollercoaster material
Placement on coaster
More than 0.5m start
Beginning on top of
coaster roof
Idea
Maximize potential
energy
COE
Black loops to clear
tubing
Start
Use conservation of
momentum for ball
bearing to gain speed and
hit lead ball, second
object
One loop of gray
insulation
Second part
Lead ball has correct
mass and angle to roll
using kinetic energy to
make around loop
Use kinetic energy to
travel up small curve into
funnel
Lead ball curves in
angled funnel, drops into
PVC pipe and lands in
clear launch pad to stop
ball.
(Note F=ma Newton’s
second law) Lead ball
stops due to another
external force.
Curve of gray insulation
Funnel, PVC pipe, launch
pad
Third part
Fourth and final part
Appendix B
Lab Notes:
1. Spring constant can be calculated using Force=k constant *displacement
2. The likelihood of elastic potential energy to be consistent is not good
3. Building material, marble, initially became stuck in large plastic tubing
4. Lead muzzle ball replaced marble
5. Conservation of momentum added onto beginning of coaster
6. Base and end of coaster built first
7. Wood glue to make four sturdy posts was not effective
8. Hot glue gun allowed base of coaster, gray insulation for loop and track to dry
quickly
9. Conservation of energy is overall concept of rollercoaster
10. Adding time factor was the challenge towards end of building coaster
11. Four different tubes attempted-gray insulation, clear tubing, black tubes, irrigation
tubing
12.
Small bearing added to start of coaster to hit the black lead ball-conservation of
momentum
Equations
(A) M1v1+m2v2=m1v1’+m2v2’ COM
(B) Potential Energy=Kinetic Energy+Energy Loss
Note: Energy Loss includes friction, heat, sound
(C)(Actual-Theoretical)/Theoretical*100=Percent