BobtheBlob Posted February 1, 2009 Report Share Posted February 1, 2009 Hello! I've got a project I have to do, where I must build a car powered by elastic bands that travels the furthest. People have gotten up to 30 metres, already, whereas I've only got 14. However, that's not my problem at the moment; all the projects I've done in this class are won by the people who test the most and get lucky, and I plan on staying to test it and tweak it everyday. However, I do have to write a report on some of the theory involved, and I'm stumped. I have to say my decisions on several things (below) and that's not too hard. It's explaining WHY I chose to do things that I'm having troubles with. Okay, here are the questions: 1. What mass should the axle have? (I have no idea for this one, actually) 2. How thick should the axle be? 3. What mass should the frame be? (Here I said small, but I don't know why I want it small...) 4. How wide/long should the frame be? 5. How will you attach the wheels to the axle? 6. How will you make sure that the wheels don't rub against the body? Why is it bad for the wheels to rub against the body? 7. Where will you put the bearings? Thanks a lot. I just need help understanding these things, and if anyone can explain any of them, I would be really thankful. -Bob Quote Link to comment Share on other sites More sharing options...
Turtle Posted February 3, 2009 Report Share Posted February 3, 2009 Hello! Hi. :) I've got a project I have to do, where I must build a car powered by elastic bands that travels the furthest. People have gotten up to 30 metres, already, whereas I've only got 14. However, that's not my problem at the moment; all the projects I've done in this class are won by the people who test the most and get lucky, and I plan on staying to test it and tweak it everyday.Okay, here are the questions: 1. What mass should the axle have? (I have no idea for this one, actually) The more massive the axle, the less likely it is to vibrate, and vibration is friction and that slows the vehicle and shortens its range. Also a more massive axle will accelerate slower but maintain its angular momentum longer than a less massive axle. (I think.) 2. How thick should the axle be? This is relative to all the other measures and best answered I think in your experiments. 3. What mass should the frame be? (Here I said small, but I don't know why I want it small...) For example, the lighter the frame the more mass you can put in that axle. 4. How wide/long should the frame be? Longer than wide I think, but you might check the aspect ratio of real cars, i.e. the ratio of length to width. 5. How will you attach the wheels to the axle? at precicesly right angles. 6. How will you make sure that the wheels don't rub against the body? follow a drafted design & testing. Why is it bad for the wheels to rub against the body? Friction slows the vehicle & so limits the range. 7. Where will you put the bearings? Out to the edges of the frame as far as possible.Thanks a lot. I just need help understanding these things, and if anyone can explain any of them, I would be really thankful. -Bob Roget that Bob. Keep us posted. :confused: Quote Link to comment Share on other sites More sharing options...
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