I Need Help Building A Mousetrap Car (I Have Details)?

Question

Okay Im building a mousetrap car/ rat-trap car for my science class. Here are some instructions:
-must move on 4 wheels
-must hold one passenger (have at least one seat)
-minimum size: 25cm length x 20cm width
-maximum size: 30cm length x 25 cm width
-constructed from any household material.
-must be able to to independently cover 4.5 meters.

Please & Thanks

Answer 1

My approach would be to tie a string on to the spring loaded hasp then wrap the other end around the axle (1/8" diameter?) in such a way that when the trap is tripped the hasp will move away from the axle. As the string is pulled it will unwind and turn the axle, causing the attached wheels to turn and the car to move. You will want to cut the end of the string at the right length so that it comes off of the axle just as the trap reaches the end of its travel.

You will need to measure the distance that the trap will move the string (from ****** to fully closed.) Then take the 4.5 meter distance and divide by the trap travel distance. That will be the minimum for the ratio of wheel-diameter to tire-diameter. For example if that minimum ratio turns out to be 30 then your wheel diameter must be at least 30 times your axle diameter. The larger the trap and the smaller the axle, the easier it will be to make it work.

I would make it front wheel drive so that I could have most of the weight on the drive axle without danger of causing it to pop a wheelie and possibly flip over backward.

Please tell us how it turns out.