Alternative Energy Vehicle

Our Vehicle

The Assignment

Our assignment was to make a prototype of what could be a real vehicle that could allow itself to move 5m and stop at 5m, without the prototype being pushed. In other words, everything that was helping the vehicle to move, had to be on the vehicle. Our vehicle also had to be safe enough to carry two passengers. These two passengers were two rolls of pennies, which had a mass of 250g. We had to transport both passengers in our vehicle while making sure that nothing happened to them, they stayed closed, they didn't fall off, or that they didn't rip.

Making Our Vehicle

The first part to making our alternative energy vehicle was to chose a vehicle and a way to make it move. Our group decided to try and make a gondola type machine. We thought that a gondola might be easier, yet more intricate than a car, and we could add more features to it. After we planned out our vehicle, the next step was to build it. We used our school's maker space to build it, and it didn't actually take us very long. First, we had to make bases for either end of our gondola. Our gondola started up high, and then went lower and gained speed as it went. For the taller pole's base, we decided to take a circular piece of wood, and on the bottom, attach four PVC pipes shooting outward in a plus sign formation for stabilization. Then, we used another PVC pipe, and this one stood as a pole to have the top of the string for the gondola on. Next, we made the other base. This one was not a hard. We ended up making something similar to the first part of this project, our trebuchet, but on a much smaller scale, and without the A frame legs. It consisted of a wooden base, and two wooden legs, and then a pole going between them to tie the other end of the string to. When we attached our gondola later, the smaller base didn't have nearly enough support, so we added a circular plastic container to the bottom, and that gives it more stability, but not enough to run on its own, so we still have to hold it down a little bit. Next we made our gondola and "cable". While the other members of my group worked on the smaller base, I went ahead and started the gondola. I took four small rectangles of wood to construct with. Those four pieces went to the bottom of the gondola, and three of the sides, leaving the front open for "a nice view". On top, we put some fishing net, so that you could sort of see our "people" in the gondola. After, we put the people in and then made sure they didn't fall out by putting two wooden poles across the open side to keep them from falling out. They can still slide around inside the gondola, but they cannot fall out.

After we built the vehicle, the next step was to test it. We were required to find these things at every interval of one meter for our calculations: distance, time, velocity, acceleration, potential energy, kinetic energy, total energy, and thermal energy. After we made sure that our machine worked, we took a slow motion video of it running, and from there we all worked on different parts of the calculations, and then at the end, filled them all in. We ran into a few problems with our energies, and had to redo a few of them, but we resolved the problems quickly. To see our final test results, scroll down to the Calculations section of this page. Once we finalized our calculations, then we put everything together and made a slideshow (below). It consists of everything included in our project and our presentation was based off of it.

Our Gondola Photos and Slideshow

Transfer of Energy vehicle presentation

Calculations and Concepts

Calculations

Alternative Energy Vehicle Calculations

Concepts

Here are the new concepts we learned during this project. All of the ones that we learned before this are explained in depth on either the Rube Goldberg Machine page, the Physics of Sports Video page, or the Fire Away! page.

Rotational Inertia

Rotational Inertia is how easily an object can rotate. Low rotational inertia means that an object will easily roll, and a high rotational inertia means that an object will have a harder time rolling, or that it rolls slower. An object's rotational inertia is determined by its center of mass. The more mass in the center, the less inertia it will have when rolling or rotating.

Data and Charts

Here are the charts we made from the data we gathering from testing the gondola.

The acceleration vs time graph shows how the gondola at the beginning sped up a lot, and then it evened out for a second, and then started decelerating.

This graph shows how when the gondola has the big drop at the beginning, the kinetic energy soars, but then settles back down for the remainder of the run.

The velocity vs time graph shows the different stages in which the velocity changed. In the beginning, the gondola cart sped up to 3 m/s and then went even faster by the time it got to the third meter. But when it hits the ground even slightly at the fourth and fifth meters, the velocity drops suddenly.

The total energy, like always, stays the same because energy is neither gained nor lost, it is just lost to somewhere else, like thermal or kinetic.

This graph shows the different stages in which some of the energy was lost to heat. It kind of went up and down a little for the first three meters, but then the energy lost was pretty consisted for the remainder of the run.

As you can see in the potential energy vs time graph, the potential energy drops immensely after the first drop that the gondola makes. From there on, the potential energy slowly drop down to nothing as it stops at 5m.

This graph is showing the relation between the distance that the gondola is moving to the time that it takes. As you can see, it is mostly linear, until the end, when it stops.

Reflection

Overall, these two projects went really well, they were both really fun, and they will definitely be some of my favorite ones throughout the year. My group worked really well together and it really showed in our final products. We worked hard, sometimes staying in at lunch to improve upon our trebuchet, and always making sure to catch up when we missed something, which we all missed one day for the alternative energy vehicle project. For the projects, collaboration was one thing that went really well for my group. The only minor disagreements we had were of how to run the test or place something on the machines, and no one was upset. Since we worked so well together, we got to really have fun and enjoy the projects, since we weren't behind because of arguing over little things. Another thing that I thought went really well was our self management and group management. We made sure that we were always in class and focused on the project that we were doing, and so, during class, we could usually make a lot of progress and get ahead of everyone else. We also sometimes would stay in at lunch to finish a part of the trebuchet, whether we were building, testing, or improving, and we all worked on that efficiently. We also made sure that all of our work was neat and organized so that if we needed to reference a blueprint or calculation, it wouldn't be hard to find. Those two of the six C's are ones that I think we really exceeded standards in for these projects.

Although they are similar, and our collaboration skills were really good for the projects, I think we could have worked on our communication a little bit more. We communicated well most of the time, but there were a few times where one or two people in the group would be getting behind in the work or lost in the discussion because others went ahead. Also, there were times that we had to redo things because we, for example, would add something to the machine that we thought we wanted, but others didn't want, so we had to spend some time undoing that. I think that our communication skills for this project were fairly good, but they could still use a little work. Another thing that I think we could work on, but didn't necessarily need all the time in the project, especially the trebuchet one is dividing and conquering the work to improve on productivity. We tended to do the same thing most of the time, and it worked out well for that project, but I know that in past projects, it has led groups to fall behind and having to rush to finish. One the other hand though, for the vehicle project, we could have divided and conquered more so that we could get extra work done. We were often a little behind for that project because all three of us were absent once from being sick during the course of the project.

In conclusion, I think that these two projects went really well, and despite the challenges we had during the building and testing of them, I am very happy and proud of our final products, and I think that they both worked out really well.