mouse trap car...help!

[Kerri]

i am suppose to build a mouse trap car for school...it must go 2m forward, pick up an object and go 2m backwards without touching it. i can get it to go forwards and pick up the object but not backwards. my design is fairly simple..there's a string attached to the axle.. the other end is attached to the part that comes down on the mouse. you pull that part back and wind up the string by turning the axle back. when the part that hits the mouse springs forward, it unravels the string and spins the wheel. but i have no idea how to make it go backwards.

 

any hot ideas would be appreciated.

[ecoli]

wait... how can something pick up an object without touching it?

[Kerri]

sorry...i meant i wasn't suppose to touch it.

[swansont]

Can you store some of the kinetic energy of the forward motion in such a way that it will move the car back? Like winding up a rubber band that will move the car backwards when it relaxes?

[Kerri]

tried that yesterday....theoretically, it should of worked...but it didn't because the axle is too small, which makes the string and elastic tangle up..thanks swansont

[Spyman]

How many mouse traps are allowed ?

 

You could have a second one which gets released (trigged) when the car picks up the object. Same setup as with the first one but in reverse direction.

[Edtharan]

There is a way to do it. You will need to have a vertical peg in the axle. You start winding the string one way around the axle, then wrap it (halfway) around the peg and you can now wind it the other way around the axle.

[J.C.MacSwell]

Can a second set of wheels be triggered to come into play on picking up the object that are geared to be in reverse? They can already be spinning in reverse but not touching the ground and the initial wheel set can continue spinning forward but be lifted off the ground.

[Rocket Man]

i'd go with edtharan on the revesrsing mechanism.

the mouse trap can close very slowly, use a fairly small spindle and large wheels to get the most distance out of the trap.

put the cart on the starting line, roll it forwards while winding the string on the spindle, get it as close as possible to the finish, put the string around the post, and wind it up backwards to the starting line.

make sure you have a lot of traction, any wheel spin could have you slamming into the object or not reaching the starting position.

 

use rat traps for more power!