# Mouse trap racer

decibel
hi, am doing a project in my physics class on a mousetrap racer...i dont know much about it, thats why am coming to you guys for help

any suggestions?...good sites? ideas maybe....its worth alot of marks and i'd really appreciate it if u'd help me...thx alot

Mentor
Could you explain a little more about what you are trying to do? Have a mousetrap propel a car?

revesz
ive never heard of a "mousetrap racer" but if you are trying to build a little car propelled by a mousetrap you can do this very easily

get a mouse trap
get four light weight wheels
and two axles

fasten the axles on the mousetrap(the rear axle must spin freely)
attach the wheels with the rear wheels locked to the axle.
tie a short string (4 inches)to the bar(swinging thing) and then tape the string onto the rear axle.when the bar swings it pulls the string, spinning the axle.

decibel
yeah its a car propelled by a mouse trap...i need to make one that can go the farthest, but having very much difficulty...if anyone can give me any tips suggestions or ideas thx

Artman
There are basically two types: those that go fast for a short distance and those that go slow for a long distance. After you decide which you would prefer to build, you can better design your trap powered car.

A few tips are to keep the car just heavy enough that the drive wheels don't spin out when power is applied, design your wheel hubs to keep friction down as much as possible.

Here is a good site on the subject:

http://www.docfizzix.com/

Homework Helper
There's got to be some rules?

Staff Emeritus
Gold Member

IED Projects

I've collected some info about mousetrap cars. My IED class just finished their mousetrap car project, and some of them turned out really well. Let us know what the constraints are, and I'll give you some tips.

Zhou Yu
Basically you have to make an object move the furthest distance powered purely by a mouse trap.

The main problem is to find a balance in the power of your vehicle. Basically what I mean is if you use a 4 inch string as suggested before you will get a racer that will accelerate for about 1 second and wheel spin and then stop.

Also if you attack a 30cm rod to the metal part of the mouse trap then it will accelerate very slowly, but will continue to release the power of the mouse trap over a longer period.

So what you want to do is maximise the power in your mouse trap.

Other things to note :-

- Make sure your mouse trap racer does NOT wheel spin as you will lose valuable energy from this.

- Make sure it goes straight, nothing worse than having a really good racer that goes around in a big arc and ends up where is started

- Have enough weight so that is does not wheel spin, but do not put excess weight as the momentum at the end does not really make up for the slow acceleration in the beginning

- Make sure that the wheels turn with minimal friction, I don't know whether I would go to the extreme of adding aerodynamic hub caps though.

Zhou Yu
I was just thinking about the mouse trap racer, and I guess there is a subtle way to increase your power even though it is actually cheating.

If you add a 30 cm rod to the mouse trap the energy will be released more slowly over a longer period of time.

However if you use a flexible 30cm rod and attack that to the mouse trap racer, then not only do you get the energy stored in the mouse trap, but you also get the elastic potential energy stored in the flexible rod.

However I do believe that if your science teacher is any good and takes a good look at your racer, he may also realise as I did that you are getting extra power by using a flexible rod.

Therefore the choice is up to you, just thought I ought to mention it since it came to mind.

We always used 45 rpm singles for wheels. I don't know if you can get those anymore. I guess CD's would work.

Njorl

Staff Emeritus
Gold Member
2 teams in my IED class used CD's, another team used rubber tires from a hobby shop (I think they were meant to go on a radio controlled car), and the third used styrofoam discs. The CD's and tires worked fine, but the styrofoam was no good because it was impossible to fasten the wheels securely. When you bolt them in tight, it crushes the styrofoam and makes an air gap, giving rise to some wobbling. It was too bad, because the car was built for speed, but it ran into the wall and was disqualified for that trial.

Homework Helper
I was thinking about this, and it occurred to me that putting a cam on the mouse trap might get you a more usefull power curve.

Ever since I took a machine shop class, my attitude about projects like this has been a bit bonkers though, so my suggestions might not be the best in the world.

decibel
hey. i asked my teacher about the constraints and wut were not aloowed to do.....he said we can do whatever we want with the cars....so any more suggestions on how to make it go farther since its gonna be marked on distance

Most teachers make a restriction against any stored energy other than the mousetrap. Otherwise you could tape it to the bumper of a Corvette and claim it does 0-60 mph in less than 6 seconds.

Njorl

Homework Helper
Originally posted by decibel
hey. i asked my teacher about the constraints and wut were not aloowed to do.....he said we can do whatever we want with the cars....so any more suggestions on how to make it go farther since its gonna be marked on distance

So you're allowed to, for example, burn the mouse trap as fuel, and then use the heat with a peltier junction to power an electric motor?

decibel
lol not sure about that man, probably not..the only thing we arent aloud to use is porbbaly fuel.

Mentor
Originally posted by NateTG
I was thinking about this, and it occurred to me that putting a cam on the mouse trap might get you a more usefull power curve.
My solution: a yo-yo. Its perfect because it gives you an adjustable acceleration curve. If you're allowed to, you can use it as the 3rd wheel in a tricycle configuration (you can argue its really two wheels close together). Just glue a wide rubber-band around each half for tires. As an added bonus, the wheel has a little mass to it which will make the car decelerate slower. The biggest challenge I see would be making a release mechanism for the pull-cord.

decibel
ok now thats what i call genius

jman4762
if the wheels spin befor it starts to move try wraping a baloon around the tires for better traction

Staff Emeritus