| Author | Message | ||
     Anonymous |
Ever seen those old toy slot cars? How about making a little railgun car and a track? | ||
| Simon Quellen Field (Sfield) |
Go for it! | ||
| kwigibow |
Wouldn't the "Railgun Car" keep gaining speed until it exeeds the speed of light? Either that, or the car will heat up and break. | ||
| Simon Quellen Field (Sfield) |
Why would you think something could exceed the speed of light? | ||
| kwigibow |
Well doesn't the railgun car keep accelerating? Wouldn't a longer track mean the faster the speed of the car at the end? What I mean is that if the track never ends, the car would be going at an incredible speed. | ||
| Simon Quellen Field (Sfield) |
Read some more about relativity. Especially the part about the tau factor. It is 1/sqrt(v*v/c*c). It defines the mass of the object as a function of velocity. It also defines the time dilation, and the Fitzgerald contraction. But from our point of view, it defines the amount of energy needed to increase the velocity. As the velocity approaches that of light, the amount of energy needed to increase the speed approaches infinity. Since you don't have infinite energy, you can't get to the speed of light. As you get close, your mass approaches infinity, which can create problems. Your length approaches zero, and the rest of the world ages and comes to an end before you quite get to the speed of light. But long before any of that happens, the frictional forces become equal to the amount of energy you are putting into the system, and the speed levels off. | ||
| kwigibow |
Okay, I see. But if your length approaches zero, and "the rest of the world ages and comes to an end", isn't that time travel? If true, wold that not mean that when you are, for example, flying in a jet plane at 500 mph, you are slightly traveling into the future? | ||
| Simon Quellen Field (Sfield) |
I travel into the future all the time. At the rate of one second per second. If I speed in my car, I travel at the same one second per second, but when I pass you by, it looks to me like your seconds are longer than mine. But a web site about building toys is not the right place to learn about relativity. There are lots of good books that explain all this stuff clearly and concisely. | ||
| kwigibow |
Alright I think I understand. Thanks! | ||
| Anonymous |
Hi, ive tried twice but failed on both accounts. If you will, post it on the board for me if you think this question is valuable 1: Can you use rubber cements on the magnets? Ive noticed they are VERY fragile and I want to make them last as long as possible. Im going guess that coating it will reduce the strength but what about just a little bit? Ive broken 4 magnets already. 2: Are you aware of how some roller coasters have launch systems called linear induction motors? They run by magnets, which are aligned on the track, and on the cart. I think this is how it works. The polarity of the magnet on the cart is constant but the polarity of the magnets on the truck can be switched. With precision and accuracy, you can pull the the cart, and as it passes right over, switch the polarity so it will push the cart away. A series of magnets on the track will accelerate the cart really fast. I was wondering if I can somehow do something similar to this with these magnets. The cart would have a magnet of its own. And below the carts is the track, and right under the thin track are magnets aligned. Perhaps if they were attached to a spinner, which spinned really fast at the exact time, causing the pull push mechanism. Any ideas? Do you think this will work? Yours truly, Brian Oh btw, your site is kick ass. and these magnets are amazing. | ||
| Simon Quellen Field (Sfield) |
The magnets are actually not very fragile. You can drop them onto concrete and they won't break. However, they are so powerful that when they jump together from a few inches, they come together with many times the force of gravity, and it is that power that causes them to break. Consider this -- if you toss one up in the air as high as you can, you can still catch it without getting hurt. But let them come together in the webbing between your fingers and they might draw blood. Coating them with rubber will prevent them from coming together, and might well prevent a lot of breakage and chipping. There is a lot of material on the web and in the library about linear induction motors. Often the moving part has permanent magnets, and the track has electromagnets. Whether the electromagnets change polarity or just switch on and off is a matter of design. The hard part is getting the timing right, and turning the switches on and off. For a toy you can probably use power transistors and a microprocessor. For something larger you will need banks of hockey-puck sized high voltage silicon controlled rectifiers. | ||
| MadDrJ Unregistered guest |
there is one other thing to keep it from hitting C. Car tracks are not meant to handle little cars going at speeds that produce gamma radiation from collision with air. You would need an indestructable track, or the car would just go flying in a random direction. Whee! And sleep, is the oldest form of time travel. | ||
| Alexander N Roberts (Whoo_mythbusters) Junior Member Username: Whoo_mythbusters Post Number: 4 Registered: 9-2005 |
Well its not time travel but time shure does seem to go really fast..haha |
