1 Engineering Fundamentals 151 Roller Coaster Project December 2 nd, 2008 Wesley Jones Chris Kibler Ryan Moran Evan Sutton
2 Each member has read and agreed upon the given format of this report. Abstract The experiment of building a roller coaster was performed in order to both show an understanding of general kinematics and energy, and that the students have the ability to perform a sample operation involving said aspects of physics with given constraints. A roller coaster was built from house hold items, items that could transport a small steel ball from location A to location B. The densest steel ball was chosen so that it could maneuver through loops after gaining energy from an initial fall. We wanted to build a non conforming roller coaster to that of the other groups, basically challenging ourselves. Several hours of designing lead us to the idea of having one loop, a funnel, a loaded mouse trap release, an elevator, and then a zig zagging drop into a metal can that would be tipped over from the force of the impact. The steel ball outperformed our own expectations by completing the course; however, the mouse trap was extremely tedious as it had to have the perfect setting so that the ball would trip it. Our finalized coaster was too unpredictable, but would occasionally get the job done. In conclusion our knowledge of physics allowed us to build our spectacle working roller coaster, but it is not one that is reliable.
3 Introduction The particular project assigned involved building a roller coaster. Said roller coaster had to be built out of standard items that could be found in a house hold and could cost no less than forty dollars. As an added bonus, the roller coaster has to last for fifteen seconds. The goal of this project is to ultimately test the students standing knowledge of physics, an introduction into later engineering if one will. Alongside the roller coaster, a power-point presentation had to made, a report written, and pictures of both the roller coaster and the team taken. All in all, the project is a fairly straightforward setup. Design Process Our design process was fairly difficult in that we wanted to be different than everyone else. We knew from the beginning that many were going to be using the spiral method to get the ball from one height to the bottom in fifteen seconds. The spiral design is neither eye candy nor fun. We spent several hours coming up with possibilities on what would be different and what to buy in order to make the roller coaster work. We put together sketches and did basic calculations to get
4 a general idea of what could work and finally decided to go with a little bit of every type of twists and turns. We finally decided on having the ball dropped from an initial height then doing a loop, afterwards there would be a funnel somewhere and an elevator to repeat a drop from a new specified height. During building our plans change drastically. We decided to keep our beginning plan of dropping and doing a loop, but we went straight to the funnel and then on to the elevator. Our original elevator was not going to work, so we had to make a half elevator ramp launch and have a second ball release from a loaded mouse trap holding a counter weight in place. From there we decided to have the second ball go into more tubing and the drop onto multiple angled tubes and run down to the bottom, finally into a half coke can that would flip upright from the final impact. All of our materials successfully cost fewer than forty dollars. Device As mentioned in the design process, our roller coaster has multiple aspects to it. First at the top, there is a tube opening for a ball to drop through. From there, the ball then goes through a loop made of tubing and then winds back up to the top of a large hand-made funnel. After spiraling down the funnel, the ball goes into more tubing which leads to a mouse trap. All of the tubing is held in place by aluminum tape and duct tape. The mouse trap has twine attached to it that runs over a pulley with a counter weight attached to it. Cleverly attached to the twin elsewhere is a ramp with a mitt, holding a second ball. When the first ball strikes and releases the mousetrap, the counterweight will pull up the ramp sending the second ball along its way into more tubing. This tubing swirls around and then goes into a ramp setup with the ball falling into multiple ramps each angled differently. Finally the ball makes a jump into the coke can and causes it to sit upright.
5 Sketch :
Bill of materials: Scrap wood $7.00 ½ in. plastic tubing $9.99 Duck tape $3.50 Pulley rigging $4.30 Metal cable $0.74 Wood Screws $1.75 Metal balls $0.40 Clear tubing $0.75 2 Yellow K nexs $0.30 Aluminum Tape $2.75 3 hinges $5.45 Coke can $0.05 TOTAL $36.98 6
7 Equations and Numbers: Using Conservation of energy we figured the theoretic velocity at point A starting from the start. The ball s mass was.00001370435 slugs mgh = mgh + ½ mv^2 (.00001370435)*(32.2)*(3.25) = (.00001370435)*(32.2)*(.625) +.5*(.00001370435)*v^2 v =.04813 ft/sec Results: Our test run results showed a completely successful attempt, unfortunately getting to the successful run was difficult. The roller coaster built was very unreliable and would only work occasionally. The mouse trap is to blame for the unreliability as our steel ball would not always trip the trap. If not for the trap error, our coaster would always run perfectly. During the actual performance, the mousetrap caused an error, not allowing for our coaster to work properly. Oddly enough, it worked again after the presentation, showing that the coaster is in fact unreliable, but works sometimes.
Points of failure: 8
9 Conclusion In conclusion, our rollercoaster was buildable, ran, and was in fact very different from our peers setups. Again showing from the results, our coaster is too inconsistent. The idea we gave through our coaster however, is theme park representative. Our coaster s uniqueness alone was enough to satisfy the team members. Though our coaster did not run perfectly during the presentation, we were still pleased knowing that we got it to run a couple of times and did in fact do something new.